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Students can Download Chapter 2 Sexual Reproduction in Flowering Plants Questions and Answers, Plus Two Botany Chapter Wise Questions and Answers helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala Plus Two Botany Chapter Wise Questions and Answers Chapter 2 Sexual Reproduction in Flowering Plants

Plus Two Botany Sexual Reproduction in Flowering Plants One Mark Questions and Answers

Question 1.
Types of pollination in Commelina is
(a) chasmogamy
(b) geitonogamy
(c) xenogamy
(d) cleistogamy
Answer:
(d) cleistogamy

Question 2.
When pollen is transferred from another of a flower to stigma of the another flower of the of the same plant, it is referred to as
(a) allogamy
(b) xenogamy
(c) geitonogamy
(d) autogamy
Answer:
(c) geitonogamy

Question 3.
For plant breeding purposes: Pollens are stored at -196°C. What is the purpose behind it?
Answer:
Stored pollens can be used as pollen banks in crop breeding programmes.

Question 4.
Pollen tube enters the embryo sac through
(a) Integument
(b) Micropyle
(c) Calaza
(d) Funicle
Answer:
(b) Micropyle

Question 5.
In flowering plants, fertilization occur in
(a) Ovary
(b) Embryo sac
(c) Nucellus
(d) Ovule
Answer:
(b) Embryo sac

Question 6.
The source of food for developing embryo is
(a) Nucellus
(b) Ovule
(c) Endosperm
(d) Anther
Answer:
(c) Endosperm

Question 7.
Out of megaspre tetrad, the functional megaspore is
(a) Any megaspore
(b) Middle megaspore
(c) Micropylar megaspore
(d) Chalazal megaspre
Answer:
(d) Chalazal megaspre

Question 8.
How many megaspore mothe cell are produced in a nuclellus
(a) 3
(b) 1
(c) 2
(d) 4
Answer:
(b) 1

Question 9.
During the development of monosporic development of embryo sac, the nucleus of the functional megaspore divides
(a) Two times
(b) Three times
(c) Onetime
(d) Repeatedly
Answer:
(b) Three times

Question 10.
Cross pollination has an advantage of
(a) Mutation
(b) polyploidy formation
(c) Genetic recombination
(d) Crossing over
Answer:
(c) Genetic recombination

Question 11.
Unisexual flowers prevent
(a) Pollination
(b) Breeding
(c) Self-pollination
(d) Cross fertilization
Answer:
(c) Self-pollination

Question 12.
The function of the filiform apparatus is
(a) To nourish the pollen grain
(b) To guide the entry of pollen tube
(c) To develop pollen tube
(d) To carry pollen tube through style
Answer:
(b) To guide the entry of pollen tube

Question 13.
Find the odd one. Hilum, Funicle, Intine, Integuments
Answer:
Intine

Question 14.
Choose the correctly matched pair.
(a) Coleorrhiza – Hollow foliar structure
(b) Perisperm- Remanents of nucellus
(c) Proembryo – mature embryo
Answer:
(b) Perisperm – Remanents of nucellus

Question 15.
Choose the correct answer. The layer of microsporangium that nourishes the developing pollen grains is
(a) Endothecium
(b) Tapetum
(c) Middle layer
(d) Epidermis
Answer:
(b) Tapetum

Question 16.
A typical angiosperm embryo sac at maturity is.
(a) 7 nucleate 8 celled
(b) 8 nucleate 8 celled
(c) 7 nucleate 7 celled
(d) 8 nucleate 7 celled
Answer:
(d) 8 nucleate 7 celled

Question 17.
The process of formation of fruits without fertilization is called.
(a) Parthenogenesis
(b) Parthenocarpy
(c) Apomixis
(d) Autogamy
Answer:
(b) Parthenocarpy

Question 18.
Identify the wrong statements regarding post – fertilization development.
(a) The ovary wall develops into pericarp
(b) The outer integument of ovule develops into tegmen
(c) The fusion nucleus (triple nucleus) develops into endosperm
(d) The ovule develops into seed
Answer:
(b) The outer integument of ovule develops into tegmen

Question 19.
Dicot emdryo consists of
(a) radicle and plumule
(b) radicle;plumule, cotyledons and sometimes endosperm
(c) radicle and plumule, cotyledons and tegmen
(d) radicle andplumule, cotyledons tegmentesta
Answer:
(b) radicle,plumule, cotyledons and sometimes endosperm

Question 20.
These process are necessary for the complete development of male gametophyte from pollen mother cell
(a) one meiotic and two mitotic divisions
(b) one meiotic cell division and one meiotic cell division
(c) two meiotic cell division and one mitotic cell division
(d) two meiotic cell division
Answer:
(a) one meiotic and two mitotic divisions

Question 21.
A bilobeddithecus anther has 100 microspore mother cells per micro sporangium. How many male gametophytes this anther can produce?
Answer:
400 male gametophytes

Question 22.
An anther with malfunctioning tapetum often failsto produce viable male gametophytes. Give one reason.
Answer:
Tapetum nourishes developing pollen grains

Plus Two Botany Sexual Reproduction in Flowering Plants Two Mark Questions and Answers

Question 1.
Pollen grains are well preserved as fossil for many years due to some characteristics

1. Name the chemical substance present in pollen wall promote such preservation
2. Give reasons.

Answer:

1. sporopollenin
2. It is the most resistant organic material and can withstand high temperatures, strong acids, and alkali. No enzymes can degrade sporopollenin.

Question 2.
One time fertilization is the characteristic feature of majority of plants but angiosperm show two times of fertilization

1. Two fusion occurs are different. Name it and write down the number of nuclei involved in such process
2. Name the products and ploidy.

Answer:

1. Syngamy. Two nuclei Triple fusion, three nuclei
2. Zygote (2n), PEN (3n)

Question 3.
Commelina, viola, and oxalis that carries both chasmogamous and Cliestogamy flowers.

1. Find out the main differences between them.
2. Give the significance of Cliestogamy.

Answer:

1. Chasmogamous flowers with exposed anthers and stigma. Cleistogamous flowers do not open at all.

2. significance of Cliestogamy:

• It ensures self pollination.
• Purity of characters is maintained.

Question 4.

1. Geitonogamy is a functional cross-pollination but not genetically. Justify?
2. In Papaya, Autogamy and Geitonogamy do not occur. Give reason.

Answer:
1. Geitonogamy is functionally cross-pollination because transfer pollen takesplace between different flowers of same plant that bear same genetic makeup.

2. Papaya is dioecios plants, because, the male and female flowers are present on different plants, which prevent autogamy and geitonogamy.

Question 5.
Wind pollination is common in grasses and water pollination in vallisneria. Give the features of these plants to facilitate pollination.
Answer:
1. Grasses

• Pollen grains are light weight and non-sticky
• Stigama is feathery.

2. Vallisneria

• Flowers do not produce nector and fragrance.
• Female flowers reach the surface of water by long stalk.

Question 6.
In most plants continuous self pollination leads to inbreeding depression while in others certain devices that help to discourage self pollination. Give any four devices.
Answer:

1. Pollen release and stigma receptivity are not at the same time.
2. Another and stigma are placed at different positions.
3. Self-incompatibility.
4. Production of unisexual flowers.

Question 7.
The micropyle remains as a small pore in the seed coat. What is its role?
Answer:
Micropyle facilitates the entry of oxygen and water into the seed during germination.

Question 8.
Draw the diagram of a typical dicot embryo and label the parts like plumule, cotyledons, radicle, and root cap.
Answer:

Question 9.
Observe the developmental stages given below and answer the following.

1. Name the process.
2. Label the stages A, B, C & D

Answer:

1. Embryogenesis (Formation of embryo)
2. A-proembryo B-globular stage C-heart shaped stage D-mature stage

Question 10.
Apomictic seeds are important in agriculture. Do you agree? Give reason.
Answer:
Yes. These seeds are formed without fertilisation hence there is no genetic variation .This feature is helpful to preserve the desirable characters for many years.

Question 11.
Give the technical terms for the following

1. Produce seeds without fertilization
2. Persistent nucellus

Answer:

1. Parthenocarpy
2. Perisperm

Question 12.
Emasculation may not be necessary. Yet bagging is necessary. Justify giving the condition when such a thing can happen.
Answer:
When the flower chosen is unisexual (female), there is no need for emasculation. Yet bagging is necessary to prevent contamination of the stigma with unwanted pollen grains.

Question 13.
Banana is a true fruit and also a parthenocarpic fruit. Justify.
Answer:
Since banana fruit is formed from ovary it is true fruit. It is parthenocarpic because the ovary develops into fruit without fertilization.

Question 14.
Arrange the following terms in the correct development sequence: Pollen grain, sporogenous tissue, microspore tetrad, pollen mother cell
Answer:
Sporogenous tissue → Pollen mother cell → Microspore tetrad → Pollen grain.

Question 15.
Some peoples live in area are subjected to allergic disease due to pollen grains.

1. Give an example for plants that produce pollen of above type?
2. Give an example for two disease?

Answer:

1. Parthenium (Carrot grass)
2. Asthma and Bronchitis

Question 16.
Typical angiosperm embryo sac is 7 celled and 8 nucleate. This condition occurs due to the development of megaspore mother cell

1. How many meiotic and mitotic division takes place
2. What you mean by monosporic development?

Answer:

1. Single meiotic division and 3 mitotic division.
2. Single functional megaspore develops into mature embryo sac.

Question 17.
Pollen allergy that causes chronic respiratory disorders in men like asthma and bronchitis. Name the causative plant.
Answer:
Parthenium or carrot grass

Question 18.
Some pollen grains cannot germinate on stigmatic surface due to the loss of viability

1. Name the factors influence the viability of pollen
2. How do the pollen grains can keep up for many years

Answer:

1. Temperature and humidity
2. Pollen grains are kept in Pollen Bank at-196 degree Celsius in liquid nitrogen.

Question 19.
Pollen tube growth occurs through the stylar region and reach micropyie of ovule. Name the special cellular thickening that guides Pollen tube
Answer:
Filiform apparatus

Question 20.
Pollengrains of many plants are found to be allergic.

1. Do they have any benefits other than the involvement in reproduction? Explain
2. Give examples.

Answer:
1. Pollen grains are rich in nutrients. In recent years pollen tablets are used as food supplements. It is used in western countries in the form of syrup and tablets. Pollen consumption has been claimed to increase the performance of athletes and race horses.

2. Parthenium, acasia

Question 21.
Zygote development leads to the formation of embryo.

1. Name the nutritive tissue that helps in the development of embryo
2. What will be the ploidy of such a tissue

Answer:

1. endosperm
2. endosperm is triploid

Question 22.
Suppose you are given four flowers namely maize, vallisneria, sunflower, and zostera.

1. State the mode of pollination in each flower.
2. Differentiate between cleistogamous and chasmogamous flowers.

Answer:

1. Maize-wind pollination
Vallisnaria-water pollination Sunflower – insect pollination

2. Cliestogamous – closed flower
Chamogamous – opened flower

Question 23.
A close relationship exist between a species of moth and the plant Yucca, where both species moth and Yucca cannot complete their life cycles without each other. Justify it.
Answer:
The moth deposits its eggs in the locule of the ovary of the Yucca flower. Flower in turn gets cross pollinated by the moth. The larvae of the moth come out of the eggs as the seeds starts developing.

Question 24.
Coconut and groundnut are oil yielding crops, point out the difference in the structure of seed.
Answer:
Coconut is an endospermous seed. Reserve food materials like fat, oil, etc. are stored in endosperm, in which the prominent part is endosperm and small sized embryo is situated at one end of the endosperm.

Question 25.
Seeds are formed in angiosperms when male and female gametes get fused. But in some plants seeds are produced without the fusion of gametes.

1. Name the process,
2. Comment.

Answer:
1. Apomixis

2. Apomixis is a form of asexual reproduction which mimics sexual reproduction. Seeds are produced from a diploid egg cell without reduction division and fertilization. Nucellar tissue surrounding the embryosac develops into an embryo.

Question 26.
In market, seedless grapes are high priced than seeded grapes. Give the method used to develop the former.
Answer:
The seedless grapes are developed through induced parthenocarpy.

Question 27.
Plant A with combined desired characters that are inherited from parents. Plant B with desired characters are pure. Find out the types of pollination leads to accurance of characters in both A & B.
Answer:
In plant A, cross-pollination leads to the occurance of mixing of characters while in Plant B self pollination and self-fertilisation results the pure character.

Question 28.
If the diploid chromosome number of a plant is 24. Find out the number of chromosomes in synergid, Antipodal, and endosperm.
Answer:
Here 2n=24, n=12 so the number of chromosomes in synergids and antipodals are 12 each. But endosperm is triploid, chromosome number is 36.

Question 29.
Pollination is aided by biotic and abiotic agents. Identify the type of pollination in Vallisneria, coconut, and grass.
Answer:

• Vallisneria -water pollination
• Coconut and grass-wind pollination.

Question 30.
Give the technical terms for the following

1. Produce seeds without fertilization
2. Persistent nucellus
3. Cotyledons of grass family
4. Protective sheath of radical.

Answer:

1. Parthenocarpy
2. Perisperm
3. Scutellum
4. Coleorhizae

Question 31.
Why do you think the zygote is dormant for some time in a fertilized ovule?
Answer:
This is because the embryo develops only after the formation of endosperm. So the zygote wait for endosperm formation which supplies food material for developing embryo.

Question 32.
In some plants self-pollination is prevented by genetic mechanism of either pollen or pistil

1. Name the process
2. Why does such process not lead to seed formation?

Answer:

1. Self incompatibility
2. It is because of interaction between the chemicals of the pollen and those of stigma (Pollen-pistil interaction)

Question 33.
If one can induce parthenicarpy through the application of growth substances, which fruits would you select to induce parthenocarpy and why?
Answer:
Watermelon, Orange and lemon because in these fruits the seeds are scattered within their edible parts and if seed are removed they become more valuable.

Question 34.
Embryosac or female gametophyte of angiospemn is 7 celled and 8 nucleate How many haploid cells are present in micropylar and chalazal part of female gametophyte of a flowering plant? Name them.
Answer:
Chalazal-Antipodals3, micropylar- Synergids 2, Egg cell 1.

Question 35.
If you squeeze seed of orange you might observe many embryos of different sizes? How is it possible?
Answer:
In orange, nucellar cells surrounding embryosac start dividing, protrude into embryosac and form many embryos.

Question 36.
If the chromosome number of plant species is 16. What would be the chromosome number and ploidy level of

1. microspore mother cell
2. endosperm cells

Answer:

1. Microspore mother cell 16
2. Endosperm cell 24

Question 37.
Observe the flow chart given below. Fill in the blank 1 and 2. Write the relevance of the process indicated as 1.

Answer:

1. Bagging
2. Artificial pollination In bagging the entry of unwanted pollen to stigmatic surface is prevented

Question 38.
Apple and mango are fruits. But they are formed in different ways. How are they formed?
Answer:
Apple is called as false fruit because thalamus develops into fruit. Here ovary is not involved. Mango is a fruit because it is formed from ovary

Question 39.
The synergids have special cellular thickening. Name the thickening and write its function.
Answer:
Filiform apparatus
It guides the pollen tube into the synergid

Question 40.
Analyse the table and fill in the blank.

Answer:

1. Thalamus also contributes to fruit formation
2. True fruit
3. Parthenocarpy
4. Banana

Question 41.

Answer:

1. a – Micropyle
2. b – Embryo sac
3. c – Nucellus
4. d – Chalaza

Question 42.
The embryo sac development in majority of flowering plants is monosporic development. Explain this type of embryo sac development.
Answer:
In this type a single megaspore mother cell of the nucellus differentiates in the ovule. Here Megaspore mother cell undergoes meiosis to form four megaspores, out of four, one megaspore becomes functional, while the other three degenerate. The functional megaspore develops into fully matured embryo sac.

Question 43.
Self incompatibility and dioecious condition are two devices for discouraging self pollination in plants. Explain the two.
Answer:
Self incompatibility – In this, pollen fail to germinate on stigma/pistil of the same flower. This is due genetic mechanism of either male parent or female parent. Dioecious condition – It is the occurrence of Male and female flowers on different plants.

Question 44.
Peculiarities of certain parts of the ovule are given below. Name the parts.

1. Protective envelops of the ovule
2. Stalk of the ovule
3. The layer of cells within the integuments
4. Junction between ovule and funicle

Answer:

1. Integuments
2. Funicle
3. Nucellus
4. Hilum

Question 45.
Geitonogamy and xenogamy are two types of pollination. Differentiate between the two.
Answer:
1. Geitonogamy
It is the transfer of pollen grains from the anther to the stigma of another flower of the same plant.

2. Xenogamy
It is the transfer of pollen grains from anther to the stigma of a different plant.

Question 46.
The inner most wall layer of microsporangium is tapetum. It is multinucleate. Justify this statement.
Answer:
Out of four wall layers of anther, tapetum is the innermost layer that nourishes the developing pollen grains.

Question 47.
Peculiarities of two types of seeds are given below. Identify the two types of seeds and give example for each.

1. Endosperm completely used by embryo.
2. Endosperm not completely used by embryo.

Answer:
1. Non-albuminous/Ex-albuminous
Eg: Pea, Groundunt, etc.

2. Albuminous
Eg: Wheat, Maize, Barley, Castor, etc.

Question 48.
The embryo of monocotyledons and dicotyledons show difference in structure. Explain the structure of dicot embryo.
Answer:
A dicot embryo has an embryonal axis and two cotyledons. The portion of embryonal axis above the level of cotyledons is the epicotyl.it terminates in plumule. The Cylindrical portion below the level of cotyledons is hypocotyl, it terminates at its lower end in radicle.

Question 49.
Occurrence of more than one embryo in a seed is called polyembryony.

1. Give two examples of polyembryony.
2. How does polyembryony occur?

Answer:

1. Citrus and mango
2. Some of the nucellar cells surrounding the embryo sac is diploid that start dividing and develop into the embryos.

Question 50.
Mature pollen grain has a vegetative cell and a generative cell. Write the peculiarities of the two cells.
Answer:
Vegetative cell – It is the bigger cell possess abundant food reserve, Large irregularly shaped nucleus. Generative cell It is the small cell that floats in the cytoplasm of vegetative cell possess dense cytoplasm and a nucleus.

Question 51.
Endosperm develops from the primary endosperm nucleus. Explain the process of endosperm development.
Answer:
The PEN undergoes successive nuclear divisions that give rise to free nuclei later cell wall formation occurs and becomes cellular eg coconut.

Question 52.
Geitonogamy is similar to autogamy. Justify this statement.
Answer:
In geitonogamy pollen grains come from the same plant. Both Autogamy and geitonogamy are come under self pollination.

Question 53.
Apomixis is an asexual form of reproduction,that mimics sexual reproduction. Substantiate this statement.
Answer:
Apomixis is a kind of asexual reproduction in which seeds are produced without fertilization. By retaining the seed habit, it mimics to sexual reproduction.

Question 54.
Observe the relationship between the first two terms and fill in the blanks.

1. Exine: Sporopollenin; Intine : …………..
2. Pistils fused: Syncarpous; Pistils free: ………….
3. Zygote : 2n ; Endosperm : …………..

Answer:

1. Cellulose and pectin
2. Apocarpous
3. 3n

Plus Two Botany Sexual Reproduction in Flowering Plants Three Mark Questions and Answers

Question 1.
Pollen grains in angiosperms ace not motile. They have to be carried to the stigma by external agents.

1. Name the process of transfer of pollen grains.
2. Write the name of three such agents.
3. Explain how it takes place in vallisnaria.

Answer:
1. Transfer of pollen grains from the anther to the stigma is called pollination.

2. Wind water and animals

3. In vallisneria the female flowers reach the surface of water by long stalk and the male flowers or pollen grains are released to the surface of water and are carried by water currents to the female flower and fertilization takes place.

Question 2.
Ramu while observing the C.S. of anther of Datura through a microscope, found fourwall layers.

1. Name the layers.
2. Write down its functions.

Answer:
1. layers:

• epidermis
• endothecium
• middle layer
• tapetum

2. The outer three layers perform protective function. Tapetum nourishes the developing pollen.

Question 3.
In flowering plants microspores are formed by meiosis and are haploid tetrads

1. How will you show the formation of microspores and male gametophyte from microspore mother cells
2. Write down the formation of embryosac and monosporic development?

Answer:
1. In the anther each cell of sporogenous tissue act as microspore mother cells (2n) which undergoes meiosis and forms four microspores (n) which are arranged in a cluster of four cells, ie.

microspore tetrad. When the anther matures the microspore dissociates from each other and develop into pollen grains. The pollen grains represents male gametophyte.

2. The nucellus of the ovule one cell is enlarged and act as megaspore mother cell (2n) which undergoes meiosis and results four megaspores (n) one of the megaspore is functional while the other three degenerates.

Only the functional megaspore develop into the embryo sac. Thus embryo sac formation from a single megaspore is called ‘monosporic’.

Question 4.
Fill up the blanks by observing the first pair.
1. Plumule: Shoot
………….: Root

2. Shoot apex: Coleoptile
Root apex: ………..

3. Ovary: Pericarp
Nucellus: ……………

4. Zygote: Embryo
…………: Endosperm

5. Syngamy: Zygote
……….: PEC

6. Ovule: Seed
…………: Seed coat

Answer:

1. Radicle
2. Coleorhiza
3. Perisperm
4. Primary Endosperm nucleus
5. Triple fusion
6. Integument

Question 5.
Diagrammatic representation of mature embryo sac is given.

1. Identify the cells that are involved in fertilization
2. Write the ploidy condition of that cells before and after fertilization.
3. Point out the role of ‘x’ in the diagram.

Answer:
1. Central cell (with two palar nuclei )and egg

2. Before fertilization – Central cell – 2n/ n+n
After fertilization – Central cell – 3n
Before fertilization – egg – n
After fertilization – egg. 2n.

3. Filiform apparatus – guides the pollen tubes into the synergids at the time of pollen germination prior to fertilization.

Question 6.
Double fertilization is the characteristic feature of angiosperms.

1. What does it mean?
2. Name the products and process.

Answer:1. It is the fertilization takes place two times.
2.

Question 7.
Haploidy, diploidy, and tripoloidy are the ploidy level of angiosperm plant parts from a seed is given below.

1. Find out the chromosome status of each part.

• Integuments outer, inner
• Nucellus
• Secondary nucleus
• Zygote

2. How will you give explanation to reduction of chromosome number from diploid to haploid?

Answer:
1. chromosome status of each part:

• Integuments outer and inner-2n(diploid)
• Nucellus-2n (diploid)
• Secondary nucleus-3n (triploid)
• Zygote-2n (diploid)

2. Chromosome number reduced due to reduction division or meiosis.

Question 8.
A bisexual self pollinating flowering plant has chromosome number 76, in its somatic cells.

1. What will be the chromosome number of its nucellus, synergids, zygote, and endosperm?
2. What is the advantage of cross pollination over self pollination?
3. Give any 2 characteristics of wind pollinated flowers.

Answer:
1. Nucellus is diploid; chromosome no is 76 Synergids are haploid;chromosome no. is 38 Zygoye is diploid; chromosome no. is 76 Endosperm is triploid its chromosome no. is 114.

2. Sexual reproduction brings about genetic recombination and results in the better Survival of the species.

3. The flowers are small and inconspicuous .they are formed in clusters. Lightweight Pollens are produced in large amount. Stigma is long and hairy.

Question 9.
Tender coconut has liquid endosperm inside it. But matured it has only solid endosperm

1. Write down the auction of endosperm.
2. How will you differentiate liquid endosperm from solid endosperm.
3. Name the part of embryo pushes deep into endosperm.

Answer:

1. Provide nutrion.
2. Liquid endosperm- provide nutrition for the development of zygote into mature embryo. Solid endosperm- provide nutrition for the future development of embryo.
3. Suspensor.

Question 10.
60% of angiosperms, pollen grains shed at 2 celled stage, but in some species pollen grains are shed at 3 celled stage.

1. Distinguish between 2 celled and 3 celled stage of pollen grains?
2. Give the significance of germ pore of exine surface

Answer:

1. In 2 celled stage pollen grains contains two cells – bigger vegetative cell and smaller generative cell. In 3 celled stage, pollen grains contains 3 cells vegetative cell and 2 male gametes
2. Germ pore is the opening through which pollen tube come out during pollen germination

Question 11.
In angiosperm 7-celled and 8-nucleate embryosac is formed from single megapore mother cell.

1. Name the process
2. Name the 3 – nuclei found in chalazal part of embryosac
3. Which is the opening of ovule that helps in the entry of pollen tube?

Answer:

1. Megasprogenesis
2. Antipodals
3. Micropyle

Question 12.
Pollen grains in angiosperms are not motile. They have to be carried to the stigma by external agents.

1. Name the process of transfer of pollen grains.
2. Write the name of three such agents.
3. Explain how it takes place in vallisnaria.

Answer:

1. Pollination.
2. Wind, water, and animals
3. In vallisnaria, mature female flower reach the surface of water by the long stalk in the same time male flowers or pollen grains are released on to the surface of water. Stigma collect the pollen grains and come inside the water.

Question 13.
Flowering plants have major devices to discourage self pollination and to increase cross pollination. Point out any four devices.
Answer:
1. Pollen release and stigma receptivity are not synchronised, ie. either the pollen is released before stigma become receptive or stigma becomes receptive much before the release of pollen.

2. In some plants the anther and stigma are placed at different positions so that pollen cannot come in contact with the stigma of the same flower.

3. Self pollination is prevented by self-incompatibility which is a genetic mechanism that prevents the pollen of the same flower or flowers of the same plant from fertilizing the ovules.

4. Production of unisexual flowers also prevents autogamy but not geitonogamy. Dioceous plants prevents both autogamy and geitonogamy.

Question 14.
Maize consists of nectar less flowers but in or chids flowers are nectary and attractive.

1. Distinguish the characteristics of both flowers based on the agents involved in the pollen transfer.
2. Some organisms involved in pollination produce foul odor. Name.

Answer:
1. Maize is a wind pollinated plant. The flowers produce large amount of light and non sticky pollen grains which helps in transportation through wind.

They possess well exposed stamens and large and feathery stigma to easily capture pollen grains. There is a single ovule in an ovary and arranged in compact inflorescence.

Orchid is an insect pollinated plant. It produce large conspicuous flowers, the small flowers are produced in clusters.

The large flowers are colourful, fragrant and rich in nectar. The insects are attracted by colour and fragrance and are often rewarded by nectar and pollen produced by the flower.

2. Flies and beetles.

Question 15.
Wind is an abiotic agent that helps in pollination. Write any six features of wind pollinated flowers.
Answer:

1. Pollen grains are light
2. Non – sticky pollen grains
3. Well exposed stamens
4. Large, feathery stigma
5. Single ovule in each ovary
6. Numerous flowers packed into inflorescence

Question 16.
Observe the figure given below and explain its structure.

Answer:
It is the structure of pollen grain, it has an outer hard layer called exine that possess prominent apertures called germ pores through which pollen tube come out.

The inner wall layer is continuous called intine. Pollen grain has two cells, a large vegetative cell, and a small generative cell.

Question 17.
Observe the diagram given below.

a) Copy the diagram, and label antipodals and synergids.
b) Explain double fertilization.
Answer:
1.

2. At first, one of the male gametes fuses with egg cell to form a diploid zygote. This is called syngamy. The other male gamete fuses with the polar nuclei to form primary endosperm nucleus (PEN). This is called triple fusion. Thus, two types of fusion occur in the embryo sac called Double fertilization.

Plus Two Botany Sexual Reproduction in Flowering Plants NCERT Questions and Answers

Question 1.
Differences between microsporogenesis and megasporogenesis. Which type of cell division occurs during this events? Name the structures formed at the end of these two events.
Answer:

• In both, the events meiosis cell division occurs.
• Microsporogenesis results in the formation of microspores while megasporogenesis forms megaspores.

Question 2.
Arrange the following terms in the correct development sequence: Pollen grain, sporogenous, microspore tetrad, pollen mother cell, male gametes.
Answer:
Sporogenous tissue ’!Pollen mother cell’!Microspore tetrad’!Pollen grain’!Male garnets.

Question 3.
What is meant by monosporic development of female gametophyte?
Answer:
The formation of female gametophyte or embryo sac from a single functional megaspore is called monosporic. The nucleus of functional megaspore undergoes 3 successive mitotic divisions to form haploid nuclei.

Question 4.
With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
Answer:
Embryo sac is an oval multicellular structure which contains 8 nuclei but 7 cells.

Question 5.
What are chasmogamous flowers? Can cross¬pollination occur in cleistogamous flowers? Give reasons for your answer.
Answer:
Chasmogamous flowers have exposed anthers and stigma. Cross pollination cannot occur in cleistogamous flowers, as such flowers do not open at all.

Question 6.
Mention two strategies evolved to prevent self pollination in flowers.
Answer:
Flowering plants have developed many devices to discourage self pollination and to encourage cross pollination.

Plus Two Botany Sexual Reproduction in Flowering Plants Multiple Choice Questions and Answers

Question 1.
Apomictic embryos in Citrus arise from
(a) synergids
(b) maternalsporophytic tissue in ovule
(c) antipodal cells
(d) diploid egg
Answer:
(b) maternalsporophytic tissue in ovule

Question 2.
Wind pollinated flowers are
(a) small, brightly coloured, producing large number of pollen grains
(b) small, producing large number of dry pollen grains
(c) large producing abundant nectar and pollen
(d) small, producing nectar and dry pollen
Answer:
(b) small, producing large number of dry pollen grains

Question 3.
Which of the following statements about sporopollenin is false?
(a) Exine is made up of sporopollenin
(b) Sporopollenin is one of the resistant organic materials
(c) Exine has apertures called germ pores where sporopollenin is present
(d) sporopollenin can withstand high temperatures and strong acids
(e) No enzyme that degradessporopollenin is so far known
Answer:
(c) Exine has apertures called germ pores where sporopollenin is present

Question 4.
Egg apparatus of angiosperms consist of
(a) one synergid and two egg cells
(b) two synergid and one egg cells
(c) one central cell, two synergid, and three antipodal cells
(d) one egg cell, two polar nuclei, and three antipodal cells
Answer:
(b) two synergid and one egg cells

Question 5.
In some organisms, karyokinesis is not followed by cytokinesis as a result of which, multinucleate condition arises leading to the formation of syncytium. The perfect example for this is
(a) appearance of a furrow in cell membrane
(b) liquid endosperm in coconut
(c) sexual reproduction
(d) fertilization
Answer:
(b) liquid endosperm in coconut

Question 6.
During the formation of embryo sac, the functional megaspore undergoes
(a) two mitotic divisions
(b) two meiotic division
(c) three meiotic division
(d) three mitotic divisions
Answer:
(d) three mitotic divisions

Question 7.
One advantage of cleistogamy is
(a) it leads to greater genetic diversity
(b) seed dispersal is more efficient and widespread
(c) seed set is not dependent on pollinators
(d) each visit of a pollinator results in transfer of hundreds of pollen grains
Answer:
(c) seed set is not dependent on pollinators

Question 8.
Which one of the following statements is not true?
(a) Pollen grains are released from anthers at 2- celled state
(b) Sporogenous cell directly behaves as he megaspore mother cell
(c) Megaspore divides twice to form an eight nucleate embryo sac
(d) Egg and synergids always lie near the micropylar end of ovule
Answer:
(c) Megaspore divides twice to form an eight nucleate embryo sac

Question 9.
Sporopollenin is chemically
(a) homopolysaccharide
(b) fatty substance
(c) protein
(d) heteropolysaccharide
Answer:
(d) heteropolysaccharide

Question 10.
Which one of the following pairs of plant structures has haploid number of chromosomes?
(a) Megaspore mother cell and antipodal cells
(b) Egg cell and antipodal cells
(c) Nucellus and antipodal cells
(d) Egg nucleus and secondary nucleus
Answer:
(b) Egg cell and antipodal cells

Question 11.
What does the filiform apparatus do at the entrance into ovule?
(a) It helps in the entry of pollen tube into a synergid
(b) It prevents entry of more than one pollen tube into the embryo sac
(c) It brings about opening of the pollen tube
(d) It guides pollen tube from a synergid to egg
Answer:
(a) It helps in the entry of pollen tube into a synergid

Question 12.
Which of the following plant products is the hardest?
(a) Lignin
(b) Cutin
(c) Suberin
(d) Sporopollenin
Answer:
(d) Sporopollenin

Question 13.
A typical angiosperm embryo sac at maturity, is
(a) 4 – nucleate – 2 celled
(b) 8 – nucleate – 7 celled
(c) 4- nucleate – 4 celled
(d) 8 – nucleate – 2 celled
Answer:
(b) 8 – nucleate – 7 celled

Question 14.
Why sometimes, even diploid offspring is produced through parthenogenesis?
(a) When offspring is produced without fertilization of diploid egg cell
(b) When offspring is produced through fertilization of diploid egg cell
(c) When offspring is produced without fertilization of haploid egg cell
(d) When offspring is produced through fertilization of haploid egg cell
Answer:
(a) When offspring is produced without fertilization of diploid egg cell

Question 15.
Pollen grains are stored for long period without losing its viability in
(a) liquid nitrogen
(b) liquidsulphur
(c) liquidsulphur at-1960c
(d) liquidsulphur at-196.50c
Answer:
(a) liquid nitrogen

Question 16.
Filiform apparatus of an embryosac is located at
(a) wall of embryosac
(b) chalazal region
(c) micropylar region
(d) middle of polar nuclei
(e) none of the above
Answer:
(c) micropylar region

Question 17.
Double fertilization is very common in
(a) angiosperm
(b) gymnosperm
(c) pteridophytes
(d) bryophytes
Answer:
(a) angiosperm

Question 18.
In Citms and mango the polyembryony is the special feature of occurance of
(a) more than one embryo
(b) more than one zygote
(c) more than one embyosac
(d) all the above
Answer:
(d) all the above

Question 19.
Triple fusion takes place in angiosperm is due to
(a) fusion of three polar nuclei
(b) fusion of synergid and polar nuclei
(c) fusion of three haploid nuclei
(d) fusion of gametes
Answer:
(c) fusion of three haploid nuclei

Question 20.
In 40 percent of angiosperms, pollen grains are shed at
(a) 2-celled
(b) 3-celled
(c) 4-celled
(d) 5- celled
Answer:
(b) 3-celled

Question 21.
In artificial hybridization bagging is done to
(a) avoid wanted pollen
(b) avoid unwanted pollen
(c) prevent the entry of unwanted pollinators
(d) allow the self pollination
Answer:
(b) avoid unwanted pollen

Question 22.
How many mitotic divisions are required for the formation of mature embryosac
(a) 4
(b) 3
(c) 5
(d) 2
Answer:
(b) 3

Question 23.
The allergies and bronchial afflictions in some people often leading to chronic respiratory disorders. It is due to
(a) pollen of parthenium
(b) pollen of hibiscus
(c) pollen of Acasia
(d) both a and c
Answer:
(d) both a and c

Students can Download Chapter 8 Biodiversity and Conservation Questions and Answers, Plus Two Zoology Chapter Wise Questions and Answers helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala Plus Two Zoology Chapter Wise Questions and Answers Chapter 8 Biodiversity and Conservation

Plus Two Zoology Biodiversity and Conservation One Mark Questions and Answers

Question 1.
The species diversity of plants on earth will be
(a) 2.4%
(b) 22%
(c) 8.1%
(d) 85%
Answer:
(b) 22%

Question 2.
Which of the following rain forest is home to more than 40,000 species of plants, 3,000 of fishes, 1,300 of birds, 427 of mammals, 427 of amphibians, 378 of reptiles and more than 1,25,000 invertebrates?
(a) Amazonian
(b) Tropical
(c) Arctic tundra
(d) Temperate
Answer:
(a) Amazonian

Question 3.
Which one of the following pairs of geographical areas shows maximum biodiversity in our country?
(a) Sunderbans and Rann of Kutch
(b) Eastern ghats and West Bengal
(c) Eastern Himalaya and Western Ghats
(d) Kerala and Punjab’
Answer:
(c) Eastern Himalaya and Western Ghats

Question 4.
Which of the following is most dangerous to wildlife?
(a) Overexploitation
(b) Man-made forest
(c) Habitat destruction
(d) Introduction of foreign species
Answer:
(c) Habitat destruction

Question 5.
The extinction of cichlid fish in the lake is due to
(a) habitat loss and fragmentation
(b) overexploitation
(c) Alien species invansion
(d) Co-extinctions
Answer:
(c) Alien species invansion

Question 6.
Aquatic environment of Kerala is facing serious threat by alien species invasion. Can you say anyone example of a species by which our indigenous plants and animals are facing greater threat.
Answer:
Eichornia

Question 7.
Write the significance of seed banks in biodiversity conservation?
Answer:
Seeds of different genetic strains of commercially important plants and other plants can be kept for a long period.

Plus Two Zoology Biodiversity and Conservation Two Mark Questions and Answers

Question 1.
Global diversity of invertebrates are shown below:-

1. Which invertebrate group shows highest biodiversity and why?
2. Among vertebrates, which group has the highest biodiversity?

Answer:

1. Insects (Arthropods), their cuticular exoskeleton gives high survival and diversity.
2. Fishes

Question 2.
Define co-extinction.
Answer:
When a species becomes extinct, the plant and animal species associated with it also become extinct. This is called co-extinction.

Question 3.
Now a days the area of sacred grooves decreased. Suggest the role of sacred grooves in conservation of biosphere?
Answer:
Sacred grooves are tracts of forests set aside by many cultures, where all the trees and wild life are given total protection.

Question 4.
Introduction of exotic species is one of the major threats to biodiversity. Analyse this statement with any four examples in your locality.
Answer:
When exotic species are introduced, some may turn invasive and cause extinction of ndigenous species.
Eg: Carrot grass, Eichornia, Lantana, African cat fish.

Question 5.
“The biological wealth of our planet has been declining rapidly and the accusing finger is clearly pointing to human activities.”

1. Mention any two activities leading to the loss of biodiversity.
2. Mention the different ways to conserve biodiversity.

Answer:

1. Habitat destruction Pollution and overexploitation
2. i) Insitu conservation – National parks, Biosphere reserve etc.
   ii) Exsitu conservation – Zoo, Botanical garden, Cryopreservation, etc

Question 6.
Arrange the following terms into two-column with proper title (Biological reserves, Zoological park, Sacred groves, National park, Cryopreservation of gametes, Wild life sanctuaries, In vitro fertilization, Botanical garden).
Answer:

Question 7.
“Conservation of nature” is a slogan which is heard all over the world. Proposed by environmentalists in this conservation of biodiversity is very important.

1. What are the different levels of biodiversity?
2. Which are the threats of biodiversity?

Answer:
1. different levels of biodiversity

• genetic diversity
• Species diversity
• Ecological diversity

2. threats of biodiversity

• Habitat loss and fragmentation
• Over-exploitation
• Alien species invasions
• Co-extinction

Question 8.
Alien species invasion is one of the causes of biodiversity loss.

1. Do you agree with this statement?
2. Site any two examples of alien species in your locality.

Answer:

1. Yes. Alien species cause decline or extinction of indigenous species. Eg: Lantana
2. Eichhornia

Question 9.
The need for conservation of biodiversity is undoubtedly inevitable for the future existence of man kind.

1. Name the strategies involved in biodiversity conservation. Give examples for each.
2. What is endemism?
3. Expand IUCN.

Answer:

1. i) Insitu conservation
Eg: Biosphere, reserve, national parks, and wild life sanctuaries.

ii) Ex-situ conservation
Eg: Zoo, Botanical garden, tissue culture, seed banks.

2. Species confined to a region and not found anywhere else. Endemic species are rich in hotspots.

3. International Union for conservation of nature and natural resources.

Question 10.
Scientists estimate that species diversity decreases as we move away from equator towards the poles. Tropical Amazonian rainforest in South America has the greatest diversity on earth.

Do you agree that there is something so special about tropics that might account for greater biodiversity. Justify your answer.
Answer:
Yes. The specialities of tropics are
They remained undisturbed for millions of years. The tropical environment is less seasonal, more constant and predictable. There is more solar energy, which contribute to higher productivity.

Question 11.
The accelerated rates of species extinctions that the world is facing now are largely due to human activities.

1. Mention the evil quatret which cause extinction.
2. Name two ex-situ method to conserve diversity.

Answer:
1. The evil quatret which cause extinction

• Habitat loss
• Overexploitation
• Alein species invasion
• Coextinction

2. Two ex-situ method to conserve diversity

• Zoo
• Botanical garden

Question 12.
“The Central Govt. declared the buffer zone to the silent valley National Park.” Predict advantages of this decision.
Protective area
Answer:

• Research/Education
• Reduce human settlement
• Reduce destruction of forest resource
• Area of park increase
• Reduce the pressure

Question 13.
Alien species are a threat to native species, justify taking examples of an animal and a plant alien species.
Answer:
The Nile Perch introduced in lake Victora in East Africa led eventually to the extinction of more than 200 species of Ci child fish in the lake. African cat fish (Clariasgariepinus) for aquaculture purpose is posing threat to the indigenous catfishes in our rivers.

Invasive weed species Eicchornia (water hyacinth). Parthenium (carrot grass). Lantana have posed a threat to our native species.

Question 14.
“We can develop a proper perspective through an analogy. The rivet popper hypothesis’ regarding the importance of species diversity to the ecosystem”. Substantiate?
Answer:
Analogy rivet popper hypothesis, used by Paul Ehrlich, indicates the importance of each species to the ecosystem. In a plane (ecosystem) all parts are joined together using thousands of rivets (species).

The extinction of a species affects the normal functioning of ecosystem, like removal of rivets of a plane. Damage of more number of species affects the ecosystem dangerously.

Question 15.
In our biosphere, immense diversity exists in all levels of biological organisation. Describe the most important levels of biodiversity.
Answer:

1. Genetic diversity: Diversity of genes within a species.
2. Species diversity: The diversity at the species level.
3. Ecological diversity: Diversity at the ecosystem level.

Question 16.
The extinction of the bird ‘Dodo’ in Mauritius island also lead to the extinctinon of the tree named ‘Calvaria major’. Explain the process that is a cause of a biodiversity loss?
Answer:
Co-extinction. When a species becomes extinct, the plant and animal species associated with it in an obligatory way also become extinct. This is called co-extinction.

Analogy rivet popper hypothesis, used by Paul Ehrlich, indicates the importance of each species to the ecosystem. In a plane (ecosystem) all parts are joined together using thousands of rivets (species).

The extinction of a species affects the normal functioning of ecosystem, like removal of rivets of a plane. Damage of more number of species affects the ecosystem dangerously.

Question 17.
‘Evil Quartet’ is a sobriquet used to describe the cause of biodiversity loss.

1. What are the evil quartets of biodiversity loss?
2. Write two ill effects of biodiversity loss?

Answer:

1. Habitat loss and fragmentation, Over-exploitation, Alien species invasion and Co-extinction.

2. effects of biodiversity loss

• decline in plant production
• Lowered resistance to environment

Question 18.
‘Amazon forests are called the lungs of the planet’ Why?
Answer:
Amazon rain forest is huge and harbor millions of species and it is estimated to produce, through photosynthesis, 20% of the total oxygen in the earth’s atmosphere.

Question 19.
The following pie diagram represents global biodiversity of invertebrates and vertebrates. Complete the graph by giving suitable group of animals to the missing sectors A and B.

Answer:

1. Insects
2. Fishes

Question 20.
‘India is one of the 12 Mega Biodiversity countries of the world’. Justify?
Answer:
India has approximately 8.1% of global species diversity, probably has more than 100000 species of plants and 200000 animal species, India has western Ghats, Indo Burma, and Himalaya as hotspots.

Question 21.
‘Gametes of threatened species can be preserved in a viable and fertile condition for a long time’

1. Identify the preservation technique used?
2. Why is it considered as an Ex-situ conservation approach?

Answer:

1. Cryopreservation
2. In ex-situ approach threatened animals/ plants/ gametes/ seeds are taken from their natural habitat and placed in special condition.

Question 22.
Categorize the following into ex-situ and in-situ conservation strategies. Seed banks, Tissue culture, sacred grooves, national parks, zoological parks, biosphere reserve, botanical garden, sanctuaries.
Answer:

• Ex-situ: Sacred groves, National Park, Biosphere reserve, Sanctuaries
• In-situ: Tissue culture, Zoological park, seed banks, Botanical garden.

Question 23.
Compare in situ and ex situ conservation strategies with examples?
Answer:
1. In-situ: Protect the whole ecosystem, its biodiversity at all levels. Eg: Biosphere reserve, national park, sanctuaries, etc.

2. Ex-situ: it is the strategy to protect threatened and endangered species which needs urgent measures to save it from extinction. Eg: zoo, botanical garden, seed bank, etc.

Question 24.

Read the statement and state whether true or false.

1.

• Endangered species are more in reptiles than in birds and mammals.
• Critically endangered species are more in birds than in reptiles and mammals.

2. What is the role of Alien species invasions in extinction?

Answer:

1.

• True
• False

2. Alien species are foreign species, when introduced, some of them turn invasive and cause decline or extinction of indigenous species.

Question 25.
What are hot spots in biodiversity? Why endemism is considered an important criteria for identifying hot spots?
Answer:
1. Hot spots: are the regions with high levels of species richness and high degree of endemism.

2. Endemism: is the number of species confined to a particular region and not found anywhere else. High degree of endemism means species richness is more and are not found anywhere else and should be protected to prevent extinction.

Question 26.
The species diversity of the plants (22%) is much less that of animals (72%). What could be the explanations to how animals achieved greater diversification?
Answer:
Compared to plants, animals have increased size and genetic variation. Also, the animals possess complex nervous system to control and coordinate various body activities.

Animals possess receptor organs for receiving various environmental stimuli and able to respond against them. The ability of locomotion is also a factor for greater diversification of animals.

Plus Two Zoology Biodiversity and Conservation Three Mark Questions and Answers

Question 1.
Amazonian rain forest has the greatest biodiversity on earth. List any two hypothesis that are proposed by the biologists to account for the greater biological diversity.
Answer:
The hypothesis are:
1. Speciation is generally a function of time; unlike temperate regions which are subjected to frequent glaciations in the past, tropical latitudes have remained undisturbed for millions of years and hence had a long time for species diversification.

2. Tropical environments are less seasonal, relatively more constant and predictable; such constant environments promote niche specialization and lead to a greater species diversity.

3. There is more solar energy available in the tropics, which contributes to higher productivity; this in turn might contribute indirectly to species diversity.

Question 2.
Introduction of exotic species is one of the major threats of biodiversity.

1. Cite any two examples of these exotic species in your locality.
2. Recent illegal introduction of a fish for aquaculture poses a threat to indigenous catfishes in our rivers. Name it.
3. How co-extinctions affects biodiversity?

Answer:

1. Eichornia- Lantana Camera
2. African catfish (clarius gariepinus)
3. When a species becomes extinct, the species associated with it in an obligatory way also become extinct. This is called co-extinction.

Question 3.
Observe the graph.

1. What does this graph represent?
2. Who proposed this relationship?
3. What does the alphabets S, C, A, Z represent?

Answer:

1. Species – Area relationships
2. Alexander Von Humboldt
3. S-Species richness A – Area Z – Slope of the line C-Y-Intercept.

Question 4.
There are many reasons, some obvious and others not so obvious, but all equally important to conserve biodiversity. They are grouped into three categories.

1. Name them.
2. Among 3 categories, which one has a scope of ‘bioprospecting’, for exploring biodiversity for products of economic importance.
3. Give examples for Ex-situ conservation.

Answer:

1. Narrowly utilitarian argument.
   Broadly utilitarian argument.
2. Narrowly utilitarian argument.
3. Zoological parks, botanical gardens, Cryopreservation, tissue culture, seed banks, pollen banks, etc.

Question 5.
Bio-diversity is not uniform throughout the world, but shows a rather uneven distribution.

1. What is latitudinal gradients in diversity?
2. What is so special about tropics that might account for their greater biological diversity.
3. Which is the area that has the highest biodiversity on earth?

Answer:

1. The distribution of diversity of plants and animals decreases as we move away from equator towards the poles.

2. biological diversity

• Tropical latitudes have remained relatively undisturbed for millions of years, thus had a long evolutionary time for species diversification.
• Tropical environments are less seasonal, relatively more constant and predictable.
• More solar energy is available which contributes to high productivity and greater diversity.

3. Amazonian rain forest in South America.

Question 6.
Observe the given graph

1. What does the above graph represent?
2. What does S and A indicate?
3. Write the significance of ‘Z’ value?

Answer:

1. Species area relationship
2. S = Species richness, A = area
3. Z is the slop of the line (regression coefficient).

Question 7.
How do the following factors affect biodiversity? Answer with suitable examples.

1. Alien species invasion
2. Co extinction
3. Overexploitation

Answer:
1. Alien species turn invasive and cause decline or extinction of indigenous species. Nile perch introduced into Lake Victoria in east Africa led to the extinction of more than 200 species of cichlid fish in the lake.

2. When a species become extinct the plants and animals associated with it in an obligatory way also become extinct, coevolved. Plant-pollinator mutualism where extinction of one species leads to the extinction of the other.

3. It happen when need turns greed and over utilization of natural resources in an irrecoverable way. Extinction of Steller’s sea cow, passenger pigeon was due to humans.

Question 8.
Narrow utilitarian, broad utilitarian and ethical arguments are the three major arguments/ reasons for conserving biodiversity. Briefly explain the basis of these three arguments?
Answer:
1. Narrowly utilitarian:
Humans get economic benefits from nature food (cereals, pulses, fruits), firewood, fibre, construction material, industrial products (tannins, lubricants, dyes, resins, perfumes) and products of medicinal importance.

2. broadly utilitarian:
Biodiversity plays a major role in ecosystem services. Amazon forest is through photosynthesis produce 20 percent of the total oxygen in the earth’s atmosphere.

Pollination is another ecosystems service by bees, bumblebees, birds, and bats. Nature provides aesthetic pleasures of watching spring flowers in full bloom and bulbul’s song in the morning.

3. Ethical:
Every species has an intrinsic value so they are conserved for future generations.

Question 9.
What are the factors responsible for the greater biodiversity in tropical regions?
Answer:

1. Tropics have remained undisturbed for millions of years and had a long evolutionary time for species diversification.
2. Constant and predictable tropical environments promote niche speciation and greater diversity.
3. More solar energy in tropics contributes higher productivity and indirectly to greater diversity.

Question 10.
Write the three components of Biodiversity. Select the component which deals with ecosystem levels of biodiversity?
Answer:

• Genetic diversity
• Species diversity
• Ecological diversity.

Plus Two Zoology Biodiversity and Conservation NCERT Questions and Answers

Question 1.
Name the three important of biodiversity.
Answer:

• Genetic diversity
• Species diversity
• Ecosystem diversity

Question 2.
How do ecologists estimate the total number of species present in the world?
Answer:
They make a statistical comparison of the species richness of exhaustively studied groups of insects of the temperate and tropical regions and extrapolate this ratio to other groups of animals and plants to calculate gross estimate of the total number of species present on the earth.

Question 3.
Give three hypothesis for explaining why tropics show greatest levels of species richness.
Answer:
Biodiversity is not uniformly distributed throughout the world. Polar regions have very little biodiversity whereas South America has the greatest biodiversity on the earth. There are many hypothesis for higher biodiversity in tropics:

1. There are no unfavourable seasons in tropics. Continued favourable environmental condition has helped tropical organisms to flourish more.

2. There is more solar energy available in the tropics due to which productivity is higher and this contribute to greater diversity.

The tropical environment is older thus allowing more time for the evolution of greater number of plants and animals.

Question 4.
What is the significance of the slope of regression in a species-area relationship?
Answer:
Alexander Von Humboldt observed that within a definite region the species richness increases upto some extent with increase in area. This relationship between species richness and area is a hyperbola fora large variety of taxa.
On a logarithmic scale it is a straight line
Log S = log C + Z log A
Where S = species richness
Z = slope of line (regression coefficient)
C = Y-intercept
A = Area
Z is generally 0.1 -0.2 regardless of taxonomic group or region i.e., when analysis of speices-area relationship is done among small areas, the values of slopes of regression are remarkably similar regardless of the taxonomic group or the region.

If analysis of species-area relationship is done among very large like a whole continent, the slope of regreesion line would be much steeper.

Question 5.
What are the major causes of species losses in a geographical region?
Answer:

• Habit loss and fragmentation
• Over-exploitation
• Introduction of exotic species
• Co-extinctions.

Question 6.
Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
Answer:
This situation may appear when alien species is introduce unintentionally or deliberately into an area. Some of them may become invasive and cause damage to indigenous species.

For example Nile perch introduced into lake Victoria in East Africa led to extinction of 200 species of Cichlid fish in the lake. Introduction of African catfish Clariasgariepinuslor aquaculture is threatening the indigenous catfishes in rivers of India.

Question 7.
What are sacred groves? What is their role in con¬servation?
Answer:
Sacred groves are sacred forest patches around places of forest. In such cases, nature is protected by prevailing religious and cultural traditions. Here tracts of forests are set aside and all plants and animals are venerated and provided with complete protection.

Some examples of sacred groves are Khasi and initial hills in Meghalaya. Aravalli hills in Rajasthan, Western ghat regions of Karnataka, Maharashtra and Sargiya, Chanda and Bastar areas of M.P. In Sikkim, Khecheopalri lake is declared sacred lake by people, thus protecting the aquatic flora and fauna.

Many rare and threatened plants have been protected in sacred groves of Meghalaya. Such areas have been found to be most undisturbed and they are usually surrounded by most degraded landscapes.

Question 8.
Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?
Answer:
Earth’s rich biodiversity is vital for indirect benefits like control of floods and soil erosion. Species richness checks soil erosion by binding the soil particles thereby reducing the rate of water velocity, hence reducing the chances of floods.

Question 9.
The species diversity of plants (22 percent) is much less than that of animals (72 percent). What would be the explanations to how animals achieved greater diversification?
Answer:
Animals bear nervous system for control and co-ordination of activities. They also bear receptors to respond to environment stimuli. Many responses become adaptive for survival. Thus animal bears higher species diversity than plants.

Plus Two Zoology Biodiversity and Conservation Multiple Choice Questions and Answers

Question 1.
Spot out the zone of our country considered as the hot spot of biodiversity and regarded as the ‘Cradle of Speciation’.
(a) Western ghats
(b) North East
(c) Himalayan base
(d) Deccan plateau
Answer:
(b) North East

Question 2.
One of the most important functions of botanical gardens is that
(a) one can observe tropical plants there
(b) they allow exsitu conservation of germplasm
(c) they provide the natural habitat for wild life
(d) they Provide a beautiful area for recreation
Answer:
(b) they allow exsitu conservation of germplasm

Question 3.
The diversity of the habitats over the total geographical area is called
(a) alpha diversity
(b) beta diversity
(c) gamma diversity
(d) delta diversity
Answer:
(c) gamma diversity

Question 4.
Biosphere reserves differ from national parks and wild life sanctuaries because in the former
(a) human being are not allowed to enter
(b) people are an integral part of the system
(c) plants are paid greater attention than the animals
(d) living Organisms are brought from all over the world and preserved for posterity
Answer:
(b) people are an integral part of the system

Question 5.
An institution, where valuable plant material-likely to become irretrievably lost in the wild or in cultivation is preserved in a viable condition is known as
(a) genome
(b) gene library
(c) gene bank
(d) herbarium
Answer:
(c) gene bank

Question 6.
Biological diversity day is
(a) 5^th June
(b) 21^st March
(c) 14^th January
d) 29^th December
Answer:
(d) 29^th December

Question 7.
Biodiversity is determined by
(a) number of individuals in an area
(b) species richness
(c) evenness
(d) Both (b) and (c)
Answer:
(d) Both (b) and (c)

Question 8.
Rare endangered and endemic taxa can be found intact and flourishing in
(a) sacred groves
(b) buffer zone
(c) tropical forests
(d) temperate forests
Answer:
(a) sacred groves

Question 9.
In situ conservation and national genetic resources can be achieved by Establishing
(a) National Park
(b) Wildlife Sanctuaries
(c) Biosphere Reserve
(d) All of a bove
Answer:
(d) All of a bove

Question 10.
IUCN, now called World Conservation Union (WCU) has its headquarter at
(a) South Africa
(b) America
(c) India
(d) Switzerland
Answer:
(d) Switzerland

Question 11.
If forest cover is reduced to half, what is most likely to happen on a long term basis?
(a) Tribals living in these areas will starve to death
(b) Domestic animals in these and joining areas will die due to lack of fodder
(c) Large biomes will become deserts
(d) Crop breeding programmes will suffer due to a reduced ability of variety of germplasm
Answer:
(c) Large biomes will become deserts

Question 12.
The management of biosphere in such a way that it may yield one greatest suitable benefit to present generation, while maintaining its potential to meet the needs of future generation is
(a) conservation
(b) aforestation
(c) fossilization
(d) over-exploitation
Answer:
(b) aforestation

Question 13.
The first Biosphere Reserve establish in India for conserving the gene pool of flora and fauna and the life style of tribals is
(a) Nilgiri Biosphere Reserve
(b) Nandadevi Biosphere Reserve
(c) Uttarakhand Biosphere Reserve
(d) Great Nicobar Biosphere Reserve
Answer:
(a) Nilgiri Biosphere Reserve

Question 14.
The government of India in 1980s has introduced a concept to work closely with the local communities for protecting and managing forests. The concept is
(a) forest research institutes
(b) panel of local communities for forest management
(c) joint forest management
(d) jhum cultivation
Answer:
(c) joint forest management

Question 15.
The percentage of forest cover recommended by the national forest policy (1988)is
(a) 33% for plains and 67% for hills
(b) 37% for plains and 63% for hills
(c) 20% for plains and 70% for hills
(d) 23% for plains and 77% for hills
Answer:
(a) 33% for plains and 67% for hills

Question 16.
The species diversity is maximum in
(a) Western Ghats
(b) Eastern Ghats
(c) Alpine meadows
(d) wetlands.
Answer:
(a) Western Ghats

Question 17.
According to the IUCN (2004), the number of species on the earth that dominates
(a) plants
(b) animals
(c) bacteria
(d) plants
Answer:
(b) animals

Question 18.
The greatest biodiversity in world is reported in
(a) Amazonian forest
(b) coniferous forest
(c) W ghats
(d) Scandinavian forest
Answer:
(a) Amazonian forest

Question 19.
Tropical environments are less seasonal and constant that lead to a greater species diversity, it is come under
(a) niche specialization
(b) species richness
(c) genetic erosion
(d) genetic equilibrium
Answer:
(b) species richness

Question 20.
The equation log S = log C +Z log A represent
(a) species richness and area
(b) genetic diversity and area
(c) allelic frequency and speciation
(d) none of the above
Answer:
(a) species richness and area

Question 21.
The extinction of Steller’s sea cow is due to
(a) overexploitation
(b) alien species invasion
(c) habitat loss and fragmentation
(d) co extinctions
Answer:
(a) overexploitation

Question 22.
The major cause of reduction in biodiversity is due to
(a) habitat fragmentation
(b) overexploitation
(c) overproduction
(d) both a and b
Answer:
(d) both a and b

Question 23.
The introduction of fish that is more serious threat to the indigenous catfishes in river, they are
(a) hilsa
(b) Clarias
(c) carp
(d) catla
Answer:
(b) Clarias

Question 24.
If two species are in obligatory relationship, the extinction of one species affect the other. This is called
(a) competitive exclusion
(b) competitive release
(c) co extinction
(d) co evolution
Answer:
(c) co extinction

Plus Two Zoology Biodiversity and Conservation SCERT Sample Questions and Answers

Question 1.

1. Arrange the following terms into two based on the mode of biodiversity conservation. Hot spots, Zoological Park, Sacred groves, wild life Safari Parks (2)
2. Fill in the blank box noted as A. (1)

Answer:

1. Hotspot and sacred grove Zoological Park and Wild Life Safari Park
2. A. Western ghats

Students can Download Chapter 7 Microbes in Human Welfare Questions and Answers, Plus Two Zoology Chapter Wise Questions and Answers helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala Plus Two Zoology Chapter Wise Questions and Answers Chapter 7 Microbes in Human Welfare

Plus Two Zoology Microbes in Human Welfare One Mark Questions and Answers

Question 1.
Which of the following plants is used as biofertilizer?
(a) Nostoc
(b) Funaria
(c) Volvox
(d) Rhizopus
Answer:
(a) Nostoc

Question 2.
Bacillus thuringiensis (Bt) strains have been used for designing novel
(a) bio-metallurgical technique
(b) bio-mineralisation processes
(c) bio-insecticidal plants
(d) bio-fertilizers
Answer:
(c) bio-insecticidal plants

Question 3.
Cyclosporin A obtained from
(a) bacteria
(b) fungi
(c) nematode
(d) virus
Answer:
(b) fungi

Question 4.
Swiss cheese’ with large holes are due to production of a large amount of CO₂ by a bacterium named
(a) Propionibacterium sharmanii.
(b) Penicillium notatum
(c) Streptococcus
(d) Monascus purpureus
Answer:
(a) Propionibacterium sharmanii

Question 5.
Clostridium butylicum produces
(a) butyric acid
(b) acetic acid
(c) aspartic acid
(d) lactic acid
Answer:
(a) butyric acid

Question 6.
Note the relationship between first two words and suggest suitable word for the fourth place. Acetobacter aceti – acetic acid, Aspergillus niger – ……..acid.
Answer:
(a) Citric acid

Question 7.
Masses of bacteria associated with fungal filaments to form mesh-like structures in secondary treatment in sewage plants. What is it called?
Answer:
Floes

Question 8.
Biogas is a terminology that we hear in our day to day life. Name the gases produced in biogas plant.
Answer:
Methane, CO₂, H₂

Question 9.
………..Is called brewer’s yeast, which is used for fermenting malted cereals and fruit juices to produce ethanol.
(a) Saccharomyces cerevisiae
(b) Clostridium butylicum
(c) Trichodermapolysporum
(d) Penciliumnotatum
Answer:
(a) Saccharomyces cerevisiae

Question 10.
Over use of chemical fertilizers harmfully affect the environment and human survival. Make discussion . points to reduce the use of chemical fertilizers.
Answer:
Organic farming and use of biofertilizers.

Question 11.
Biogas is a terminology that we hear in our day to day life. Name the gases produced in biogas plant.
Answer:
Methane, CO₂, H₂

Plus Two Zoology Microbes in Human Welfare Two Mark Questions and Answers

Question 1.
Find out the name of the microbes from which Cyclosporin A (An Immunosuppressive drug) and statins (Blood cholesterol-lowering agent) are obtained.
Answer:

• Cyclosporin A-Trichoderma polysporum
• Statins – Monascus purpureus

Question 2.
The dough which is used for making foods such as dosa and idli give a puffed-up appearance.

1. What is the prodess involved here?
2. Name the gas produced?

Answer:

1. Fermentation
2. CO₂

Question 3.
Microbes synthesis a number of industrial product like beverages and antibiotics.

1. Name the microbes involved in the production of beverages.
2. Classify the types of alcoholic drinks based on raw material and processing.

Answer:

1. Saccharomyces cerevisiae (Brewer’s yeast)
2. Alcoholic drinks without distillation – Wine and Beer Alcoholicdrinkswith distillation-Whisky, brandy, rum.

Question 4.
Identify the microorganism.

1. Symbiotic association with roots of leguminous plant.
2. Microbe responsible for the preparation of dough.
3. Bacteria used in the production of biogas.
4. Microbes responsible for the conversion of milk to curd.

Answer:

1. Rhizobium
2. Saccharomyces cerevisiae
3. Methanobacterium
4. Lactobacillus

Question 5.
Your family has decided to minimize the use of LPG (Liquid petroleum gas). List out the steps that you would adopt to install a biogas plant at your house premises.
Answer:

1. A concrete tank in which bio-wastes are collected and a slurry of dung is fed.
2. A floating cover over the slurry.
3. An outlet connected to pipe to supply biogas.
4. Another outlet to remove spent slurry to be used as fertiliser.

Question 6.
BOD testing is widely used in detecting the polluting potential of different water sources. How BOD helps in analysing the polluting potential? BOD is the measure of organic matter in the water. The greater the BOD of wastewater more is its polluting potential.
Answer:
Auto immune response
Eg: Rhuematoid arthritis, Myasthenia gravis.

Question 7.
Microbes play an important role in production of biogas.

1. Name the group of bacteria, which produce biogas. Give an example.
2. Which are the common habitat of these bacteria.

Answer:

1. The bacteria are collectively called methanogens. Eg: Methanobacterium
2. Methanogens are commonly found in, Anaerobic sludge Rumen of cattle, Cattle dung, etc.

Question 8.
In sewage treatment floes play a major role.

1. What are floes?
2. State their role in effluent treatment and their ultimate fate in sewage treatment tank.

Answer:

1. Floes are masses of bacteria associated with fungal filaments to form mesh-like structures.
2. Floes consume the organic matter in the effluent and reduces the BOD. Then the effluent passed into settling tank, where floes are allowed to sediment forming activated sludge.

Question 9.
In which food would you find lactic acid bacteria? Mention some of their useful applications.
Answer:
In curd Other Applications are,

1. Increases nutritional quality
2. Checking disease-causing microbes

Question 10.
Microbes can be used to decrease the use of chemical fertilizers and pesticides? Explain how this is accomplished.
Answer:
By switch to organic farming using biofertilizers like bacteria, fungi, and cyanobacteria.
Eg: Rhizobium, Glomus, Anabaena, Nostoc etc.

Question 11.
A person has suffered a heart attack due to a floating clot in his coronary artery.

1. Name the bacterium that can save him.
2. Mention its product and its action.

Answer:

1. Strep to cocus
2. Strep to kinase. It is a clot-buster

Question 12.
“Biogas become popular on now a days as a source of energy.” Mention the merits of Biogas.
Answer:

• Clean & Ecofriendly fuel
• Produce fewer pollutants
• Can be easily stored and transported
• Recycling ensures
• Renewable energy.

Question 13.
Microbes play a dual role when used for sewage treatment as they not only help to retrieve usable water but also generate fuel. Write the points how this happens.
Answer:
Heterotrophic microbes naturally present in sewage are used. Vigorous growth of aerobic microbes as floes use up organic matter in effluent and reduce BOD of waste water.

Other kinds of bacteria grow in it anaerobically and digest the bacteria and fungi called floes. As they digest floes, as mixture of CH₄, H₂S and CO₂ (biogas) are evolved, which can be used as a fuel.

Question 14.
Common yeast is known as Baker’s yeast and also as Brewer’s yeast. Justify.
Answer:
Common yeast is employed in the fermentation of

1. Dough, used for making bread, cakes in bakeries.
2. Fruit juices and malt in breweries for the production of alcoholic beverages: hence it is known as both as baker’s and brewer’s yeast.

Question 15.
What is the difference in production of wine and whisky?
Answer:
Wine is produced without distillation while whisky is produced by distillation.

Question 16.
Match column A with column B and column C

Answer:

Question 17.
Milk is converted to curd by the action of micro organisms

1. Name the microorganism that convert milk to curd.
2. Explain the superior nutritional quality of curd over milk.

Answer:

1. LAB (Lactic Acid Bacteria)
2. Increasing Vit. B₁₂, Check disease-causing microbes in stomach.

Question 18.
Ramu likes fresh juices than bottled juices

1. As a plus two biology student, give your opinion about his habit.
2. Why bottled juices are clearer than fresh juices? Critically evaluate its harmful effects.

Answer:

1. bottled juice is not good for health,
2. Use of Pectinase and Protease make clear solutions. It contains large number of preservatives and other chemicals.

Question 19.
Swiss cheese contains large holes

1. Describe the formation of large holes in cheese
2. Name the end product of the process mentioned

Answer:

1. Production of large amount of CO₂ by a bacterium called Propionibacterium sharmanii during fermentation
2. CO₂

Question 20.
Farmers cultivate pea plant as an intermediate crop in the paddy fields. After harvesting they remove all parts of the pea plant from their crop land

1. Do you think the action of removing all parts of the pea plant from the field is a good agricultural practice.
2. Justify your answer.

Answer:

1. No,
2. The root nodules of leguminous plants(Pea plant) have symbiotic association of Rhizobium. These bacteria fix atmospheric nitrogen which is used by the plant as nutrient.

Question 21.
Many pathogenic microbes and large amounts of organic matter are found in sewage.

1. During sewage treatment primary sludge is produced. Define Primary sludge.
2. Compare it with activated sludge.

Answer:

1. All solids that settle during primary treatment are called primary sludge.
2. During secondary treatment the effluent is passed into a settling tank where the bacterial ‘floes’ are allowed to sediment. This sediment is called activated sludge.

Question 22.
The untreated sewage when discharged directly into rivers cause aquatic pollution and spread various diseases. Suggest suitable remedies to overcome the problem. Give emphasis on Ganga action plan and Yamuna action plan.
Answer:
The aim of Ganga Action Plan and Yamuna Action Plan is to save major rivers of our country from pollution. These plan is proposed to set up of sewage treatment plants and discharge less polluted water into the rivers.

This helped to avoid many water-borne diseases and through which major rivers can be conserved.

Question 23.
“BOD is commonly calculated as an index of water pollution”.

1. Do you agree with the statement? Why?
2. Expand BOD.

Answer:

1. Yes, BOD test measures the rate of uptake of oxygen by micro organisms in a sample of water, indirectly. BOD is the measure of the organic matter present in water.
2. biochemical oxygen demand.

Question 24.
Expand the terms given below.

• KVIC
• IARI

Answer:

• KVIC: Khadi and Village Industries Commission
• IARI: Indian Agricultural Research Institute.

Question 25.
Today we cannot imagine a world without antibiotics.

1. Define antibiotics?
2. Name the first antibiotic to be discovered.

Answer:

1. Antibiotics are chemical substances, which are produced by some microbes and can kill or retard the growth of other disease-causing microbes.
2. Penicillin

Question 26.
Complete the table.

Answer:

Question 27.
Your local self-government is newly introducing a project on waste management and installing Biogas plants at all homes. As a plus two biology student, briefly explain the working of biogas plant.
Answer:
The biogas plant consists of a concrete tank (10-15 feet deep) in which bio-wastes are collected and a slurry of dung is fed.

The biogas plant has an outlet, which is connected to a pipe to supply biogas to nearby houses. The spent slurry is removed through another outlet and used as fertiliser. The biogas thus produced is used for cooking and lighting.

Question 28.
Farmers cultivate pea plant as an intermediate crop in the paddy fields. After harvesting they remove all parts of the pea plant from their crop land

1. Do you think the action of removing all parts of the pea plant from the field is a good agricultural practice.
2. Justify your answer.

Answer:

1. No,
2. The root nodules of leguminous plants(Pea plant) have symbiotic association of Rhizobium. These bacteria fix atmospheric nitrogen which is used by the plant as nutrient.

Question 29.
Many pathogenic microbes and large amounts of organic matter are found in sewage.

1. During sewage treatment primary sludge is produced. Define Primary sludge.
2. Compare it with activated sludge.

Answer:

1. All solids that settle during primary treatment are called primary sludge.
2. During secondary treatment the effluent is passed into a settling tank where the bacterial ‘floes’ are allowed to sediment. This sediment is called activated sludge.

Question 30.
The untreated sewage when discharged directly into rivers cause aquatic pollution and spread various diseases. Suggest suitable remedies to overcome the problem. Give emphasis on Ganga action plan and Yamuna action plan.
Answer:
The aim of Ganga Action Plan and Yamuna Action Plan is to save major rivers of our country from pollution. These plan is proposed to set up of sewage treatment plants and discharge less polluted water into the rivers.

This helped to avoid many water – borne diseases and through which major rivers can be conserved.

Question 31.
Three water samples namely river water, untreated sewage water, and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B, and C, but the Laboratory attendant did not note which was which. The BOD values of the three samples A, B, and C were recorded as 20mg/L, 8 mg/L, and 400 mg/L, respectively. Which sample of the water is most polluted? Why?
Answer:
The sample C is more polluted. So the bottle labelled C was untreated sewage water, because it has the highest BOD 400mg/L.

BOD is a measure of organic matter present in water. The greater the BOD of waste water, more is its
polluting potential.

Plus Two Zoology Microbes in Human Welfare Three Mark Questions and Answers

Question 1.
Match column A with column B and column C

Answer:

Question 2.
Name the household products, the following microbes help to produce.

1. LAB
2. Saccharomyces cerevisae
3. Propionibacteriumsharmanii

Answer:

1. LAB – Curd
2. Saccharonyces cerevisiae (Baker’s yeast) – Bread
3. Propionibacterium Sharmanii – Swiss cheese

Question 3.
One of the most significant discoveries of the twentieth century was the production of antibiotics from microbes.

1. How will you define antibiotic?
2. Name the first antibiotic and who discovered it?
3. Name some deadly diseases which can be treated by antibiotics.

Answer:

1. Antibiotics is a chemical substance produced by some microbes and can kill or retard the growth of other disease-causing microbes.
2. Alexander Fleming discovered the first antibiotic Penicillin, while working on Staphylococcus bacteria.
3. Plague, Whooping cough, Diphtheria, Leprosy, etc.

Question 4.
Match the following.

Answer:

Question 5.
Many microbes are used for the commercial production of chemicals, acids, enzymes, etc.
1. Give examples for acid-producing microbes and the acids.
2. Name the enzymes produced by microbes and their use.
3. What are

• Cyclosporin A
• Statins

Answer:
1.

• Aspergillusniger(fungus)-Citric acid
• Acetobacter aceti (Bacterium) – Acetic acid
• Clostridium butylicum (Bacterium) – Butyric acid
• Lactobacillus (Bacterium) – Lactic acid

2.

• Lipases – In detergents for removing oily stains from the laundry.
• Pectinases (and Proteases) – clearing bottled juices.
• Streptokinase – As ‘clot buster’ for removing clots from blood vessels of heart patients

3.

• Cyclosporin A is a bioactive molecule used as an immuno suppressive agent in organ transplant patients. It is produced by a fungus Trichoderma polysporum.
• Statins are blood-cholesterol lowering agents produced by the yeast Monascus purpureus.

Question 6.
Microbes play a major role in the treatment of sewage, which is a main cause of pollution. Some terms related to sewage treatment are given. What are they?

1. Sewage
2. B.O.D.
3. Floes

Answer:
1. Sewage is the muncipal waster water generated in cities and towns everyday, which contains large amount of organic matter and pathogenic microbes.

2. Biological Oxygen Demand (B.O.D) refers to the amount of 02 that would be consumed, if all the organic matter in one litre of water were oxidized by bacteria.

3. Floes are masses of bacteria associated with fun-gal filaments to form mesh like structures.

Question 7.
Microbes are widely applied as biocontrol agents in biological farming approach.

1. What is Biocontrol?
2. What is the advantage of this over conventional chemical methods?
3. Give two examples for biocontrol.

Answer:
1. Biocontrol refers to the use of biological methods for controlling plant diseases and pests.

2. Chemicals like insecticides and pesticides are toxic and extremely harmful to human beings and animals. They also pollute the environment. Use of biocontrol measures reduce the dependence on toxic chemicals.

3.

• Bacillus thuringiensis (Bt)
• Trichoderma

Question 8.
A part of the flow chart showing sewage treatment is given below. Complete it with other steps involved in sewage treatment.

Answer:

Plus Two Zoology Microbes in Human Welfare NCERT Questions and Answers

Question 1.
What is the key difference between primary and secondary sewage treatment?
Answer:
Primary treatment involves the removal of large sized floating and suspended solids by physical methods, while secondary treatment involves decomposition of organic matter by microbial action.

Question 2.
Do you think microbes can also be used as source of energy? If yes, How?
Answer:
Yes.
The microbes present in activated sludge are digested an aerobically to generate an inflammable biogas or gobar gas which is used as source of energy.

Question 3.
Microbes can be used to decrease the use of chemical fertilizers and pesticides. Explain how this can be accomplished?
Answer:
By the use of biofertilizers and biological pest control method. The use of chemical fertilizers and pesticides can be reduced.

The fertility of the soil depends not only on its chemical composition but also on the presence of useful microbes in it, which enrich the nutrient quality of the soil. The main source of biofertilizers are bacteria, fungi and cyanobacteria.

Question 4.
Three water samples namely river water, untreated sewage water, and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labeled A. B. and C, but the laboratory attendant did not which was which. The BOD values of the three samples A, B, and c were recorded as 20 mg/L. 8 mg/L and 400 mg/L respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?
Answer:

1. Sample A-Secondary effluent
2. Sample B – River Water
3. Sample C – Untreated Sewage water.

Question 5.
Find out the name of the microbes from which cyclosporine A and Statins are obtained.
Answer:

1. Cyclosporin A-Trichoderma Polysporum (a fungus)
2. Statins – Monascus Purpureus (a yeast)

Question 6.
Find out the role of microbes in the following and discuss it with your teacher –

1. Single-cell protein (SCP)
2. Soil.

Answer:
1. SCP:-
It is protein-rich microbial biomass which can be used as food and feed. It has low-fat content. The common SCP are Spirulina. Yeast and Fusarium graminearum.

2. Soil:-
Microbes play an important role in decomposition of organic matter and thus cause mineralization of the soil. The are used as biofertilizers and biopesticides.

Question 7.
Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer, Biogas, citric acid, Penicillin, and curd.
Answer:
Penicillin, biogas, curd, critic acid. penicillin fan antibiotic is used to cure a number of bacterial diseases.

Question 8.
Bacteria cannot be seen with the naked eyes but can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why?
Answer:
Bacteria can be grown and multiplied on nutritive culture media in aseptic conditions to form colonies which can be transported from the home to biology laboratory where these can be demonstrated under a microscope. In homes easily available source of microbial culture is curd. It is with Lactic acid bacteria.

Question 9.
Give examples to prove that microbes release gases during metabolism.
Answer:
1. Puffing up of dough, during making of dosa, idli or bread, is due to production of CO₂ gas during the fermentation process.

2. Appearance of large holes in “swiss cheese” is due to C0₂ produced during fermentation by the bacterium Propionibacterium sharmanii.

3. During secondary treatment of sewage in sewage treatment plants, a number of gases like methane, H₂S and CO₂ are produced during microbial digestion of organic compounds.

4. Methanogens(e.g. Methano bacterium) present in the rumen (a part of stomach) of cattle are being used in biogas plants to produce biogas as energy source.

Question 10.
In which food would you find lactic acid bacteria? Mention some of their useful applications.
Answer:
1. Lactic acid bacteria (LAB) are commonly found in milk and under suitable condition, these multiply and produce acids which coagulate and partially digest the milk proteins and change the milk into curd.

2. LAB are also found in the human stomach where these prevent the growth of certain disease-causing microbes.

Question 11.
In which way microbes have played a major role in controlling diseases caused by harmful bacteria?
Answer:
Antibiotics are the chemical substances which are derived from certain useful microbes and are employed to kill or retard the growth of disease-causing microbes.

So antibiotics are being used in controlling a number of bacterial diseases like cholera, pneumonia, typhoid, syphilis, whooping cough, diphtheria, etc.

Question 12.
Name any two species of fungus, which are used in the production of the antibiotics.
Answer:

Question 13.
Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve using microbes.
Answer:

Plus Two Zoology Microbes in Human Welfare Multiple Choice Questions and Answers

Question 1.
Which of the following was used as a bioweapon agent in America?
(a) Botulinuni
(b) Anthrax (Bacillus anathracis)
(c) Polio vims
(d) AIDS virus
Answer:
(b) Anthrax (Bacillus anathracis)

Question 2.
During an aerobic digestion of organic waste, such as in producing biogas, which one of the following is left undegraded?
(a) Hernicellulose
(b) Cellulose
(c) Lipids
(d) Lignin
Answer:
(d) Lignin

Question 3.
Azolla is used as a biofertilizer because it
(a) multiplies very fast to produce massive bio
(b) has association of nitrogen-fixing Rhizobium
(c) has association of nitrogen-fixing cyanobacteria
(d) has association of Mycorrhiza
Answer:
(c) has association of nitrogen-fixing cyanobacteria

Question 4.
Which is a bioinsecticide?
(a) cactoblastis cactorum
(b) Anabaena
(c) Bacillus thuringiensis
(d) Rhizobium
Answer:
(c) Bacillus thuringiensis

Question 5.
One of the major difficulties in the biological control of insect pest is that
(a) the method is less effective as compared with the us of insecticides
(b) the predator does not always survive when transferred to a new environment
(c) the predator develops a preference to other diets may itself become a pest
(d) the practical difficulty of introducing the predat specific area
Answer:
(b) the predator does not always survive when transferred to a new environment

Question 6.
Biogas is pathogen-free because
(a) anaerobic digestion removes pathogens and bacteria
(b) it is toxic to pathogens
(c) during decomposition, it produces antibiotics
(d) cattle dung is pathogen-free
Answer:
(c) during decomposition, it produces antibiotics

Question 7.
Green manures are prepared from
(a) Saccharum officinarum
(b) Zea mays
(c) Crotalariajuncea
(d) Sorghum Vulgare.
Answer:
(c) Crotalariajuncea

Question 8.
Insecticide obtained from neem plant is
(a) pyrethrin
(b) pyrethroid
(c) thiocarbamate
(d) azadirachtin
Answer:
(d) azadirachtin

Question 9.
Biogas production from waste biomass with the help of methanogenic bacteria is
(a) multi-step process
(b) one-step process
(c) two-step process.
(d) three-step process
Answer:
(a) multi-step process

Question 10.
From which one of the following plants, the insecticide pyrethrum is prepared?
(a) Vetivera
(b) Cymbopogon
(c) Chrysanthemum
(d) 7ephrosia
Answer:
(c) Chrysanthemum

Question 11.
lPM (Integrated Pest Management) involves
(a) tissue culture
(b) biological control
(c) biofertilizers
(d) confusion technique
Answer:
(b) biological control

Question 12.
The lactic acid bacteria is involved in
(a) conversion of milk into curd
(b) conversion of curd into ghee
(c) lactic acid fermentation
(d) both a and c
Answer:
(d) both a and c

Question 13.
In the case of the ‘Swiss cheese’ with large hole is due to the production of
(a) CO
(b) CO₂
(c) CH₄
(d) C₂H₅OH
Answer:
(b) CO₂

Question 14.
Roquefort cheese is made by
(a) bacteria
(b) fungi
(c) nematode
(d) mycoplasma
Answer:
(b) fungi

Question 15.
The important distillation products are
(a) whisky
(b) brandy
(c) rum
(d) all the above
Answer:
(d) all the above

Question 16.
Alexander Fleming observed that the chemical produced by mould in one of his unwashed culture plates restricted the growth of
(a) streptococcus
(b) staphylococcus
(c) pneumococcus
(d) bacillus
Answer:
(b) staphylococcus

Question 17.
The microbe that produce butyric acid belongs to
(a) virus
(b) mycoplasma
(c) bacteria
(d) fungi
Answer:
(c) bacteria

Question 18.
The ‘clot buster’ for removing clots from the blood vessels of patients is mainly obtained from
(a) streptococcus
(b) staphylococcus
(c) pneumococcus
(d) bacillus
Answer:
(a) streptococcus

Question 19.
Trichoderma polysporum is helpful to the patients subjected to organ-transplant because it produce immunosuppressive agent called as
(a) interferon
(b) cyclosporine A
(c) Streptokinase
(d) statins
Answer:
(b) cyclosporine A

Question 20.
Which one of the following microbe produce Statins
(a) Bacillus thuringiensis
(b) Saccharomy cescerevisiae
(c) Trichoderma polysporum
(d) Monascus purpureus
Answer:
(d) Monascus purpureus

Question 21.
The major part of activated sludge is subjected to
(a) aerobic digestion
(b) anaerobic digestion
(c) both a and b
(d) none of the above
Answer:
(b) anaerobic digestion

Plus Two Zoology Microbes in Human Welfare SCERT Sample Questions and Answers

Question 1.

1. Name the microorganism which produced butyric acid. (1)
2. ‘Secondary treatment is sewage water treatment is called biological’. Justify. (1)

Answer:

1. Clostridum butylicum
2. The primary effluent is passed into large aeration tanks, is carried with the help of aerobic bacteria.

Students can Download Chapter 6 Human Health and Disease Questions and Answers, Plus Two Zoology Chapter Wise Questions and Answers helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala Plus Two Zoology Chapter Wise Questions and Answers Chapter 6 Human Health and Disease

Plus Two Zoology Human Health and Disease One Mark Questions and Answers

Question 1.
The immunoglobulin present in mother’s milk is
(a) lgD
(b) lgE
(c) 1gM
(d) lgA
Answer:
(d) lgA

Question 2.
Short-lived immunity acquired from mother to foetus across placenta or through mother’s milk to the infant is categorized as
(a) active immunity
(b) passive immunity
(c) cellular immunity
(d) innate or non-specific immunity
Answer:
(b) passive immunity

Question 3.
Malarial parasite is introduced into the blood of man as a
(a) meta crypto zoite
(b) schizont
(c) oocyte
(d) sporozoite
Answer:
(d) sporozoite

Question 4.
The genes concerned with the production of cancer are called
(a) cancer genes
(b) carcino genes
(c) carcinomas
(d) oncogenes
Answer:
(c) carcinomas

Question 5.
A drug called morphine is obtained from
(a) Rauwoiffia serpentina
(b) Cannabis sativa
(c) Cajanuscajan
(d) Papaversomniferum
Answer:
(d) Papaversomniferum

Question 6.
Observe the relationship between the first two words and fill in the blanks.

1. Ascariasis: Ascaris, Elephantiasis:-
2. Cannabinoids: Hashish, Opioids:-

Answer:

1. Wuchereria
2. Heroin

Question 7.
Choose the odd one with reason. Malaria, Pneumonia, Cancer, Hyphoid.
Answer:
Cancer.
All others are infectious diseases.

Question 8.
“Death rate due to Cancer is high now a days” Name the gene casing cancer.
Answer:
Oncogene

Question 9.
One your classmate is suspected to be having typhoid and you advise him to consult a doctor and to do the confirmation test. Name the medical confirmation test.
Answer:
Widal test

Question 10.
Amoeboid dysentery is caused by a protozoan parasite. Name the parasite.
Answer:
Entamoeba histolytica

Question 11.
Identify the odd one
(a) Malaria
(b) Elephantiasis
(c) Typhoid
(d) Dengue
Answer:
(c) Typhoid; all others are vector bone disease

Question 12.
WBC, PMNL monocytes and natural killer cells are then examples of
(a) Physical Barriers
(b) Physiological barrier
(c) Cellular barrier
(d) Cytokine barriers
Answer:
(c) Cellular barrier

Question 13.
When the immune system attacks our own cells, the process is called……….
(a) Innate immunity
(b) Acquired immunity
(c) Auto immunity
(d) Humoral immunity
Answer:
(c) Auto immunity

Question 14.
AIDS is caused by HIV. Which type of virus is HIV?
(a) Adenovirus
(b) Retrovirus
(c) Bacteriophage
(d) Rhinovirus
Answer:
(b) Retrovirus

Question 15.
Mother’s colostrum contains Ig G. What type of immunity it confers to the infants?
(a) Passive immunity
(b) Active immunity
(c) Cell mediate immunity
(d) Innate immunity
Answer:
(a) Passive immunity

Plus Two Zoology Human Health and Disease Two Mark Questions and Answers

Question 1.
Malaria is a disease, man has been fighting since many years.

1. Name the protozoan which cause Malaria and the toxic substance released by it.
2. Which part of the body is mainly affected by the parasite?

Answer:

1. Plasmodium (P.Vivax, P.Malaria, P.Falciparum) Haemozoin
2. The parasite initially multiply within liver cells and then attack RBC, resulting in their rupture, which causes the release of haemozoin.

Question 2.
Cancer can be cured completely. Write down two diagnostic and treatment methods.
Answer:
1. Diagnostic methods:

• Biopsy
• CT Scan
• MRI etc.

2. Treatments:

• Surgery
• Radiation therapy
• Immunotherapy etc.

Question 3.
Select the odd one from the given groups and assign reason.

1. Gonorrhea, Typhoid, Syphilis, Chlamydiasis
2. Spleen, Tonsil, Lymph nodes, Thymus

Answer:

1. Typhoid. All others are sexually transmitted diseases.
2. Thymus. All others are secondary lymphoid organs.

Question 4.
Fill in the blanks in the different columns of the table given below.

Answer:

1. Insect bite
2. Ringworm
3. Rhinovirus
4. Internal bleeding, fever, muscle pain

Question 5.
Maintenance of Personal and Public hygiene is very important for prevention and control of many infectious diseases. Justify this statement.
Answer:
Infectious diseases are spread mainly through air, food, drinking water, vectors, etc. Personal and public hygiene help to prevent infectious diseases.

Not only that balanced diet, regular exercise, vaccination, proper waste disposal, control of vectors, etc. are also necessary to prevent diseases and for achieving good health.

Question 6.
Complete the table.

Answer:

1. ELISA
2. Typhoid

Question 7.
“The soldiers of a country kills their own king”. Keeping this mind, in our body can you find a similar situation in some person. Give examples.
Answer:
Auto immune response
Eg: Rhuematoid arthritis, Myasthenia gravis.

Question 8.
During a discussion, your friend said that “AIDS can also be transmitted through food and touch.”

1. How HIV infects human body?
2. What clinical test is used to confirm AIDS?

Answer:

1. Method of infection is through body fluids, sexual contact, contaminated needles, blood transfusion from mother to foetus,
2. Western blot/ELISA

Question 9.
You are working as a volunteer in an AIDS awareness programme. If a person comes to you and asks the following questions, how will you answer?

1. How HIV multiplies in host cell?
2. What are the precautions to be taken to prevent AIDS?

Answer:
1. HIV, being a retrovirus, enters the macrophages, where the RNA replicates to form viral DNA. It incorporated into the host cell’s DNA and directs infected cells to produce viral particle.

2. Avoid unsafe sex with a stranger.

• Use of disinfected needles.
• Avoid sharing of injection needles.
• Screening of blood before transfusion.

Question 10.
A sportsperson was tested positive for cannabinoid. What are these? From where are these extracted?
Answer:
Cannabinoids are group of chemicals interact with cannabinoid receptors in the brain. Cannabis sativa.

Question 11.
More than a million Indians suffer from cancer and a large number of them die from it annually. Unlike normal cells, cancer cells possess some unique features. List any two of them.
Answer:

1. Loss of contact inhibition
2. Metastasis

Question 12.
“Prevention is better than cure”. Can you suggest some important preventive measures of STD’s.
Answer:

1. Avoid sex with a stranger/multiple partner.
2. Always use condoms during coitus.

Question 13.
Give the scientific term for the following.

1. Spreading of cancer cell into distant place.
2. Hypersensitivity to certain substance

Answer:

1. Metastasis
2. Allergy

Question 14.
A group of five members spent in a room with dust. One among them shows some allergic responses.

1. Name the chemicals released during allergy and which cells produce them.
2. Which are the drugs used to reduce the symptoms quickly?

Answer:

1. Histamine and serotonine from mast cells,
2. Anti-histamine drugs, adrenalin, and steroids.

Question 15.
What is the role of histamine in inflammatory response? Name few drugs which reduce the symptoms of allergy.
Answer:

1. The histamine acts as allergy mediator which cause blood vessels to dilate. It is released by mast cells.
2. Antihistamine, steroids, and adrenaline quickly reduce the symptoms of allergy.

Question 16.
Name one plant and the additive drug extracted from latex. How does this drug affect the human body?
Answer:
Papaver somniferum (Poppy plant)

1. Morphine is obtained from this plant.
2. It is an opioid that binds to specific receptors in the central nervous system and gastro intestinal tract; it slows down the body functions.

Question 17.
How does the transmission of each of the following diseases take place?

1. Amoebiasis
2. Malaria
3. Ascariasis

Answer:
1. Amoebiasis, By ingesting quadrinucleated cysts of Entamoeba histolytica with food and water. The cysts are carried from faces of patient to food and water.

2. Malaria. Plasmodium (malarial parasite) is trans-mitted from sufferer to healthy one by biting of female Anopheles mosquito.

3. Ascariasis. The disease is transmitted by taking contaminated food and water with embryonated egg of Ascaris.

Question 18.
Match the following.

Answer:

Question 19.
The graph given below shows the response of attack of an influenza virus in a patient repeatedly during the interval of 40 days.

1. What is the difference in the response during the first and second attacks?
2. Give the reason for this change.

Answer:

1. In secondary response, more antibody is produced than primary response.
2. In secondary response, the memory cells help to produce more antibody rapidly than the primary response.

Question 20.
Elaborate the diagnostic methods used for early detection of cancer.
Answer:
X ray, CT Scan, and MRI Scan, Specific antibody against cancer cell, identification of cancer genes.

Question 21.
You meet an HIV patient. He is unaware about the transmission method of HIV. What precautions will you suggest him so that HIV cannot be spread to others?
Answer:
Use disposable needles, use of condoms, safe blood transfusion, safe sex, controlling drug use.

Question 22.
Write the difference between malignant tumor and benign tumor?
Answer:
1. Benign tumors: normally confined to their original location and do not spread to the other parts of the body.

2. Malignant tumors: it is the mass of proliferating cells invading and damaging surrounding normal cells quickly dividing and have property called metastasis.

Question 23.
Briefly explain the methods used to treat cancer.
Answer:
Surgery, radiation therapy, chemotherapy, immunotherapy.

Plus Two Zoology Human Health and Disease Three Mark Questions and Answers

Question 1.
Name the type of immunity that is present at the time of birth in humans. Explain any two ways by which it is accomplished.
Answer:
Innate immunity is present at the time of birth. This is accomplished by providing different types of barriers to the entry of the foreign agents into our body. It consists of four type of barriers:

1. Physical barrier- Skin and mucus
2. Physiological barrier- Acid in the stomach, saliva in the mouth and tears.
3. Cellular barrier- Neutrophils and macrophages.
4. Cytokine barrier-Interferons.

Question 2.
Match the following.

Answer:

Question 3.
A person injured in a road accident and requiring an urgent immune response was brought to a doctor.

1. What did the doctor immediately do?
2. What kind of immunity was he providing to the patient?
3. Define this kind of immunity.

Answer:

1. Performed antibodies are injected
2. Passive immunity
3. Passive immunity is developed by injecting the performed antibodies, which neutralize the antigen.

Question 4.
Fill in the blanks.

Answer:

1. a – Pneumonia
2. b – Fever, chills, cough, and headache
3. c – Microsporum
4. d – Ascariasis
5. e – Ascaris lubricoids
6. f – Salmonella typhi

Question 5.
Lymphoid organs play an important role in immunity, where maturation and proliferation of lymphocyte takes place.

1. What are the primary lymphoid organs?
2. Name the lymphoid tissue located within the lining of major tracts.
3. What are the secondary lymphoid organs, which provide sites for interaction of lymphocytes with the antigen.

Answer:

1. Bone marrow and Thymus
2. MALT (Mucosal Associated Lymphoid Tissue)
3. Spleen, Lymph nodes, Tonsils, Peyer’s patches

Question 6.
Write the single word for the following.

1. Glycoproteins secreted by virus-infected cells.
2. Antibody-dependent immunity.
3. The type of antibody produced during allergy.

Answer:

1. Interferons
2. Humoral immunity
3. lgE

Question 7.
A patient consult a doctor with the following symptoms.

• Constipation
• Abdominal pain and cramps
• Stools with excess mucous and blood clots.

1. Identify the disease.
2. Name the microbe that causes this disease.
3. Write the mode of transmission of this disease.

Answer:

1. Amoebic dysentery
2. Entamoeba hystolytica
3. Contaminated food and drinking water

Question 8.

1. Identify the molecule.
2. Name the types.
3. Copy and label the diagram.

Answer:

1. Immunoglobin
2. lgA, lgM, lgE, lgG

Question 9.
A doctor noticed a small internal growth in the abdomen of a patient. Doctor suspects it as cancer.

1. Name any two possible Carcinogens.
2. Which biomedical technique is used for the diagnosis of cancer.
3. Suggest the methods to treat this disease.

Answer:
1. Ionising radiation (X-ray, gamma-ray)

• Oncogenic viruses
• Chemicals like nicotine, polycyclic hydrocarbons, etc.

2. Biopsy/Scanning/MRI/Sonography etc.

3. Chemotherapy, Surgery, Hormone therapy, Radiation therapy, and Immune therapy.

Question 10.
Complete the table.

Answer:

Question 11.
Identify the disease from the symptoms given below table.

Answer:

Question 12.
Complete the table

Answer:

Question 13.
A doctor noticed a small internal growth in the abdomen of a patient. Doctor suspects it as cancer.

1. Name any two possible Carcinogens.
2. Which biomedical technique is used for the diagnosis of cancer.
3. Suggest the methods to treat this disease.

Answer:
1. Ionising radiation (X-ray, gamma-ray)

• Oncogenic viruses
• Chemicals like nicotine, polycyclic hydrocarbons, etc.

2. Biopsy/Scanning/MRI/Sonography etc.

3. Chemotherapy, Surgery, Hormone therapy, Radiation therapy, and Immune therapy.

Question 14.
The symptoms of some diseases are given below. Identify the disease, name the parasite which cause the disease and write the mode of transmission.

1. Weakness, Stomach pain, sustained high fever, constipation, etc.
2. Fever, chill, cough, headache, bluish fingernails, etc.
3. Constipation, abdominal pain, cramps, stools with mucus and blood, etc.
4. Dry, scaly lesions on skin, nails, and scalp, itching, etc.

Answer:

1.

• Typhoid
• Salmonella typhi
• Contaminated food and water

2.

• Pneumonia
• Streptococcus pneumoniae
• Droplet infection/ sharing glasses and utensils etc.

3.

• Amoebic dysentery (Amoebiasis)
• Entamoeba histolytica
• Contaminated food and drinking water

4.

• Ringworms
• Fungi (Microsporum/Trichophyton Epidermophyton)
• Soil and towels, clothes, or comb of infected persons

Plus Two Zoology Human Health and Disease NCERT Questions and Answers

Question 1.
What measures would you take to prevent water-borne diseases?
Answer:

1. Drinking clean water.
2. Periodic cleaning and disinfection of water tanks and reservoirs.

Question 2.
Discuss with your teacher what does suitable gene means, in the context of DNA vaccines.
Answer:
The term Suitable Gene refers to that specific segment of DNA that will be modified in the host to produce protein to kill specific disease-causing organisms.

Question 3.
Name the primary and secondary lympboid organs.
Answer:
1. Primary Lymphoid organs: Bone marrow and thymus.

2. Secondary Lymphoid organs: Spleen, lymph nodes, Peyer’s patches (small intestine) and mucosal associated lymphoid tissues (MALT).

Question 4.
Expand the following terms:

1. MALT
2. CM I
3. AIDS
4. NACO
5. HIV

Answer:

1. MALT:- Mucosal – Associated Lymphoid Tissue
2. CMI – Cell Mediated Immunity
3. AIDS -Acquired Immuno Deficiency Syndrome
4. NACO – National AIDS Control Organisation
5. HIV – Human Immuno Deficiency Virus.

Question 5.
Differentiate the following and give example of each:

1. Innate and acquired immunity
2. Active and passive immunity

Answer:

Question 6.
What are the various public health measures, which you would suggest to safeguard us against infectious diseases?
Answer:

1. Proper disposal of wastes and excreta
2. Periodic cleaning and disinfection of water sources.
3. Observing standard practices of hygiene in public catering.
4. Avoiding close and prolonged contact with infected persons suffering from contagious diseases.
5. Eliminating the breeding places of the vectors of infectious diseases like malaria.

Question 7.
What are the various routes by which transmission of human immunodeficiency virus takes place?
Answer:
Various modes of transmission of HIV are sexual intercourse; use of contaminated hypodermic needles and syringes; blood transfusion organ transplantation; artificial insemination; from infected mother to baby during parthurition (30%) and breast feeding.

Question 8.
What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?
Answer:
HIV attacks the helper-T cells inside the host cell, viral RNA syntheses single-stranded DNA on it in the presence of enzyme reverse transcriptase. Single-stranded DNA separates from viral RNA and forms its complimentary copy to form double-stranded DNA which is incorporated into hosts cell DNA.

The viral DNA transcribes large number of RNA particles, each of which gets surrounded by a proteinous capsid to complete viral particles.

Finally, the host helper T- cell is lysed and many HIV viruses are released. Each of these infects new Helper T-cells. So there is progressive decrease in the number of Helper-T- cells.

Question 9.
Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/ herself from such an influence?
Answer:
One of the reasons for alcohol drinking or drug abuse is peer pressure. So one can be easily influenced by one’s friends to take alcohol/drugs. So one must avoid undue peer pressure with one’s own will power may seek the help of one’s parents and teachers.

Question 10.
How transmission of each of the following diseases takes place?

1. Amoebiasis
2. Malaria
3. Ascariasis
4. Pneumonia

Answer:
1. Amoebiasis: Direct and oral. The tetranucleate cysts are ingested with contaminated food and water.

2. Malaria: Indirect and inoculative. The sporozoites are introduced along with the saliva of vector female Anopheles mosquitoes.

3. Ascariasis: Direct and oral. Capsules with second juveniles are ingested with contaminated food and water.

4. Pneumonia: Airborne or through droplet infection or aerosols or contaminated utensils. Bacterial cysts are spread by sputum of the patients.

Question 11.
So that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher.
Answer:
Initially, one may be motivated to take alcohol or drugs by many causes like peer pressure, liking of taste, desire for excitement, advertisements, false belief of enhanced performance, etc.

But the regular consumption of alcohol or drugs develops dependency on it called addition. Then if alcohol or drug is not available to an addict, then he/she start showing certain unpleasant characteristics called withdrawal symptoms.

Question 12.
Explain what is meant by metastasis.
Answer:
The cancerous cells of malignant tumour initially show slow growth called the latent stage, but later their growth becomes very rapid causing over-crowding and damage to the normal cells. This phase of secondary rapid growth of cancer cells is called metastasis.

In this, the cancer extends to the neighbouring tissues like the roots of a tree. Small pieces of primary tumour break off and are carried to other parts of the body by the blood or lymph, where these form the secondary tumors.

Question 13.
In which way the study of biology has helped us to control infectious diseases?
Answer:
Advancements achieved in biological science have helped us to control infectious diseases by:

1. Discovery of vaccines and their timely use in immunization programmes have helped in controlling and even eradicating certain infections diseases.
2. Discovery of antibiotics and many other drugs helped to treat a number of infectious diseases.

Question 14.
In your view, what motivates the youngsters to take to alcohol of drugs and how can this be avoided?
Answer:
1. Main motivating factors which stimulate the youngsters to take to alcohol or drug are:

• Peer pressure
• Desire for excitement
• Liking of taste
• To escape from frustrations Family’s history
• Curiosity due to advertisements
• False belief of enhanced performance
• To overcome the hardships of daily life.

2. Alcohol or drug abuse can be avoided by:

• To identify the reason of addition and to take remedial measures
• Avoid undue peer pressure
• By giving proper education and counseling to the addict.
• Seeking help from parents, teachers and trusted friends
• Seeking professional and medical help

Plus Two Zoology Human Health and Disease Multiple Choice Questions and Answers

Question 1.
The letter T in T-lymphocyte refers to
(a) thyroid
(b) thalamus
(c) tonsil
(d) thymus
Answer:
(d) thymus

Question 2.
Use of antihistamines and steroids give a quick relief from
(a) allergy
(b) nausea
(c) cough
(d) headache
Answer:
(a) allergy

Question 3.
Which of the following is a pair of viral diseases?
(a) Ringworm, AIDS
(b) Common cold, AIDS
(c) Dysentery, common cold
(d) Typhoid, tuberculosis
Answer:
(b) Common cold, AIDS

Question 4.
Globulins contained in human blood plasma are primarily involved in
(a) defence mechanisms of body
(b) osmotic balance of body fluids
(c) oxygen transport in the blood
(d) clotting of blood
Answer:
(a) defence mechanisms of body

Question 5.
In the cell mediated immuno response, T- lymphocytes divide and secrete
(a) antigens
(b) plasmogens
(c) collagens
(d) cytokines
Answer:
(d) cytokines

Question 6.
During an allergic reaction, the binding of antigens to IgE antibodies initiates a response, in which chemicals cause the dilation of blood vessels and a host of other physiological changes. Such chemicals are
(a) interferons
(b) hormones
(c) histamines
(d) acetylamine
Answer:
(c) histamines

Question 7.
Genetic material found in Fluman Immunodeficiency virus(HIV) is
(a) double-stranded RNA
(b) single-stranded RNA
(c) double-stranded DNA
(d) single-stranded DNA
Answer:
(b) single-stranded RNA

Question 8.
HIV virus affect in AIDS patient,
(a) cytotoxic T-cell
(b) M-Ncell
(c) suppressor cell
(d) helper T-cells
Answer:
(d) helper T-cells

Question 9.
Lung tuberculosis is caused by
(a) Pseudomonas aeruginosa
(b) Mycobacterium tuberculosis
(c) Streptococcus pneumoniae
(d) Escherichia coli
Answer:
(b) Mycobacterium tuberculosis

Question 10.
If the person shows the production of interferons in body, chances are that he is suffering from
(a) anthrax
(b) malaria
(c) measles
(d) tetanus
Answer:
(c) measles

Question 11.
Morphine obtained from opium is
(a) latex
(b) pome
(c) alkaloid
(d) tannin
Answer:
(c) alkaloid

Question 12.
Which of the following is an opiate narcotic?
(a) Morphine
(b) LSD
(c) Amphetamines
(d) Barbiturates
Answer:
(d) Barbiturates

Question 13.
Assertion LSD and marijuana are clinically used as analgesics. Reason Both these drugs suppress brain function.
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion
(b) Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
(c) Assertion is true but Reason is false
(d) Both Assertion and Reason are false
Answer:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Question 14.
Cocaine, an alkaloid is obtained from the leaves of
(a) Erythroxylon coca
(b) Ephedra sp. [Manipall
(c) Digitalis purpurea
(d) Papaversomnferum
Answer:
(a) Erythroxylon coca

Question 15.
Alcohol is the most socially accepted narcotic. Excessive consumption of alcohol leads to
(a) state of hallucination
(b) loss of memory
(c) suppression of brain function
Answer:
(c) suppression of brain function

Question 16.
Which of the following is not hallucinogen?
(a) Heroin
(b) LSD
(c) Marijuana
(d) Charas
Answer:
(a) Heroin

Question 17.
Widal test is used to detect
(a) pneumonia
(b) typhoid
(c) cholera
(d) whooping cough
Answer:
(b) typhoid

Question 18.
The organism responsible for the disease pneumonia in humans which infects the alveoli of the lungs is
(a) Streptococcus
(b) Haemophilus
(c) bacillus
(d) both a and b
Answer:
(d) both a and b

Question 19.
Rhino viruses which cause one of the most infectious human ailments they are
(a) common cold and chicken pox
(b) common cold
(c) diphtheria
(d) mumps
Answer:
(b) common cold

Question 20.
The malignant malaria is serious and fatal. It is due to
(a) Plasmodium falciparum
(b) P. malaria
(c) P. vivax
(d) none of these
Answer:
(a) Plasmodium falciparum

Question 21.
Bite of Anopheles mosquito causes the rupture of RBCs and release a toxic substance called as
(a) saxitoxin
(b) aflatoxin
(c) haemozoin
(d) none of the above
Answer:
(c) haemozoin

Question 22.
Houseflies act as mechanical carriers and transmit the parasite from faeces of infected person to food and food products. This results
(a) malaria
(b) elephantiasis
(c) amoebiasis
(d) chikungunya
Answer:
(c) amoebiasis

Question 23.
Virus-infected cells secrete a kind of proteins which protect non-infected cells from further viral infection. It is belonged to
(a) Cytokine barriers
(b) Physical barriers
(c) Physiological barriers
(d) Cellular barriers
Answer:
(a) Cytokine barriers

Question 24.
The yellowish fluid colostrum secreted by mother during the initial days of lactation contains antibodies (IgA) to protect the infant, this is an example for
(a) active immunity
(b) passive immunity
(c) autoimmunity
(d) cell-mediated immunity
Answer:
(b) passive immunity

Question 25.
The antibodies produced as immune response to allergens come under
(a) lgE
(b) lgA
(c) lgM
(d) lgG
Answer:
(a) lgE

Question 26.
Due to genetic and other unknown reasons, the body attacks self-cells and cause the damage to the body
(a) passive immunity
(b) active immunity
(c) auto immunity
(d) innate immunity
Answer:
(c) auto immunity

Plus Two Zoology Human Health and Disease SCERT Sample Questions and Answers

Question 1.
A. Complete the table by using hints from brackets. (Haemophilus influenzae, Common cold, Salmonella Ityphi, Running nose & Nasal congestion, Pneumonia, Ascariasis, Sustained fever 39°C – 40°C, Malaria) (3)

Answer:

1. A-Salmonellatyphi
2. B – Sustained fever 39-400C
3. C – Common cold
4. D – Running Nose and Nasal congestion
5. E – Pneumonia
6. F – Haemophilus influenza

OR

B. Categorise the following organs into two, with appropriate headings. Thymus, Spleen, Bone marrow, Peyer’s Patches(3)
Answer:

1. Primary Lymphoid Organs
2. Thymus, Bone marrow
3. Secondary Lymphoid Organs
4. Spleen, Peyer’s Patches

Students can Download Chapter 5 Evolution Questions and Answers, Plus Two Zoology Chapter Wise Questions and Answers helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala Plus Two Zoology Chapter Wise Questions and Answers Chapter 5 Evolution

Plus Two Zoology Evolution One Mark Questions and Answers

Question 1.
S L Miller’s closed flask contained
(a) CH₄
(b) H₂
(c) NH₃ and H₂ O
(d) All of these
Answer:
(d) All of these

Question 2.
Wings of insects and birds are
(a) analogous
(b) homologous
(c) vestigial
(d) atavism
Answer:
(a) analogous

Question 3.
Convergent evolution is shown by
(a) homologous organ
(b) analogous organ
(c) vestigial organ
(d) All of these
Answer:
(b) analogous organ

Question 4.
Which of the following is the most primitive ancestor of man?
(a) Homo habilis
(b) Homo neanderthalensis
(c) Australopithecus
(d) Ramapithecus punjabicus
Answer:
(d) Ramapithecus punjabicus

Question 5.
Thoms of Bougainvillea and tendrils of Cucurbila are examples of
(a) analogous organs
(b) homologous organs
(c) vestigial organs
(d) retrogressive evolution
Answer:
(b) homologous organs

Question 6.
More than one adaptive radiation appeared to have occurred in an isolated geographical area is called as………..
Answer:
Convergent evolution

Question 7.
Explain Oparin and Haldane Hypothesis.
Answer:
According to Oparin and Haldane, the life could have originated form pre-existing non-living organic molecules.

Question 8.
In a class seminar, Varun says that some scientists believe that the life originated form the spores reached on earth from outer space. Name this theory of origin of life.
Answer:
Theory of panspermia

Plus Two Zoology Evolution Two Mark Questions and Answers

Question 1.
Identify the Experimental set up in Evolution and answerthe following.

1. Name the Experiment.
2. Explain the significance of the given experimental setup.

Answer:
1. Urey and Miller experiment.

2. In laboratory primitive atmosphere is created. In closed flask (Spark discharge apparatus) CH₄, H₂, NH_3, and water vapour is taken and heated at 8000c. S.L. Miller observed that the formation of amino acids. This supports theory of chemical evolution.

Question 2.
Fossils are the written document of evolution.

1. Name the branch of biology which deals with the study of fossils?
2. How can we calculate the age of fossil?

Answer:

1. Paleontology
2. Radioactive – dating

Question 3.
Examine carefully the details given and group similar one in the table. Give suitable title for each column. Analyse the importance of each group in evolution. (Wings of bat, flipper of whale, wings of butterfly, forelimbs of horse, wings of birds, rudementary body hair, wisdom teeth, vermiform appendix of man, patagium of draco).
Answer:

Question 4.
Choose the correct answers. (Convergent evolution, Gene flow, Adaptive radiation, Divergent evolution)

Answer:

Question 5.

Figure shows white-winged moth and dark-winged moth on a tree trunk.

• in unpolluted area
• in polluted area

a. Which evolutionary theory is depicted by this figure?
b. What is industrial melanism?
c. Can you give any other example for this theory?
Answer:
a. Theory of Natural selection by Darwin

b. Industrial melanism is the development of dark colouration in populations that are exposed to industrial air pollution.

c. – Resistance of Mosquitoes against DDT.
– Resistance of some microbes against some antibiotics.

Question 6.
The two scientists set up their experimental apparatus by using following components.
(CH₄, NH₃, H₂, Condenser, Electrode, Vaccum pumps, boiling chambers, gas chamber, ‘U’shaped tubes)

1. State chemical evolution theory.
2. Who experimentally proved this concept?

Answer:

1. Chemical evolution states that first form of life could have come from pre-existing non-living organic molecules, for formation of diverse organic molecules from inorganic constituents.
2. Urey Miller

Question 7.

1. Evolution is a departure from Hardy Weinberg equilibrium. Comment on this statement.
2. What are the five factors that affect Hardy Weinberg equilibrium?

Answer:
1. Hardy-Weinberg principle says that allele frequencies in a population are stable and constant from generation to generation.

The gene pool remains constant, which is called genetic equillibrium. Disturbance in this equillibrium, ie. change of frequency of alleles in a population results in evolution.

2. Five factors are

• gene migration or gene flow
• genetic drift
• Mutation
• genetic recombination
• Natural selection

Question 8.
Abiotic origin of life is in progress on a planet other than earth. Based on the origin of life on earth what should be the conditions on the planet.
Answer:

• High Temperature
• Presence of gases such as C, H, N
• Anaerobic environment
• Torrential rain
• High energy radiation
• Primordial soup

Question 9.
As you know Lamarckism and Darwinism are two theories explaining the mechanism of evolution.

1. Write the difference between acquired characters of Lamarck and variation theory of Darwin. Specify.
2. How Darwin defined variation as a key to evolution?
3. Give one example for Darwinism and Lamarckism.

Answer:
1. Acquired characters are inherited to the next generation. According to Darwin, only favourable varia¬tion is inherited to the next generation, which leads to speciation (origin of species).

2. According to Darwin variations are of two types, namely, somatic variation (in body) and genetic variation, which is a key to evolution.

3. Lamarckism – Origin of long necked giraffe. Darwinism – Industrial melanism in peppered moth.

Question 10.
The following diagram represents the operation of Natural selection on one trait.

1. Identify the type of selection.
2. What is meant by Natural selection?

Answer:

1. Stabilising selection
2. Organism with favourable variations are selected by nature and those without them are rejected. This is called Natural selection.

Question 11.
Construct a flow chart showing Darwinism using following points. (Over production, Struggle for existence, Variation Natural Selection, Gurvival of the fittest, origin of species).
Answer:

Question 12.
Name the gases filled in the gas chamber to design the condition of primitive earth.
Answer:
Methane, Ammonia, H₂, water vapour

Question 13.

1. Identify the type of evolutionary process shown here.
2. Give one more example for this.

Answer:

1. Adaptive radiation
2. Darwin’s finches

Question 14.
“Darwin’s finches are excellent example for adaptive radiation.’’

1. Name the place where Darwin’s finches found.
2. Explain adaptive radiation.

Answer:

1. Galapago islands
2. Adaptive radiation is a process of evolution of different species in a geographical area starting from a point and literally radiating to other areas of geography.

Question 15.
“Galapagos islands are the living laboratory of evolution”.

1. Who made this statement?
2. Name the small dark birds in these islands.

Answer:

1. Darwin
2. Darwin’s finches

Question 16.
Arrange them in chronological order. Homo sapiens, Dryopithecus, Australopithecus Homo habilis Homo erectus Answer:

• Dryopithecus
• Australopithecus
• Homo habilis
• Homo erectus
• Homo sapiens

Question 17.
Write one word for the following:

1. Single-step large mutation causing speciation.
2. Allelic frequencies remain constant from generation to generation.
3. Evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography.
4. Change in gene frequencies occur by chance in small population.

Answer:

1. Saltation
2. Hardy-Weinberg equilibrium
3. Adaptive radiation
4. Genetic drift

Question 18.
How do Darwin’s finches illustrate adaptive radiation?
Answer:
Original stock of seed-eating finches migrated to different habitats, adapted to different feeding methods, by altered beak structure, evolved into different types of finches.

Question 19.
Odd man out. Justify your answer.

• Recombination
• Genetic drift
• Gene migration
• Natural selection
• Mutation
• Speciation

Answer:
Speciation
All others are mechanisms for variation that leads to the origin of species (speciation).

Question 20.

1. Identify the evolutionary phenomenon shown? Explain.
2. What is founder effect?

Answer:

1. Adaptive radiation
2. The effect where original drifted population becomes founders is called founder effect.

Question 21.
Prior to industrialization, there were far more white winged moths on trees than melanised moths in England. However, after industrialization, the distribution pattern of these two kinds of moths reversed. What does the above observation indicate? Explain giving reasons.
Answer:
It indicates that predators will spot a moth against a contrasting background.

1. After industrialization, the tree trunks became dark due to deposition of soot and smoke; under such a condition, the white winged moths stood out conspicuously and easily detected by the predators and hence they reduced in number.

2. The dark-winged moths could merge with the black colour and they escaped the predators and hence increased in number.

Question 22.
‘Darwin finches are the example of adaptive radiation’. Justify.
Answer:
The beak modifications in finches occurred due to difference in food gathering and feeding habitats of different Islands

Question 23.
Arrange the following into two categories under the heading.
Analogous organ and homologous organ.
Eyes in Human beings and octopus.
Flippers of penguin and dolphin.
Vertebrate hearts.
Thorns and tendril.
Wings of butterfly and birds
Forelimb of vertebrates
Answer:

Question 24.

1. Explain Hardey-Weinberg equilibrium?
2. Mention the factors affecting Hardey-Weinberg equilibrium.

Answer:
1. Allele frequencies in a population are stable and constant from generation to generation. (p2+2pq+q2 =1), p, q are individual frequencies of alleles.

2. The factors are gene migration, genetic drift, mutation, genetic recombination, and natural selection.

Plus Two Zoology Evolution Three Mark Questions and Answers

Question 1.
During his voyage, Darwin went to Galapago islands and observed an amazing diversity of particularly, some black birds, called Finches. Darwin’s Finches represent a best example for an evolutionary phenomenon.

1. Name the phenomenon.
2. In which feature, they showed diversity?
3. Give another example forthis phenomena.

Answer:

1. Adaptive radiation
2. Showed variety in beak structure based on food habits – from seed-eating to insectivorous, vegetarian, etc.
3. Australian Marsupials.

Question 2.

Diagrammatic representation of Miller’s experiment is shown.
1. Label the parts a,b,c,d.

2. Miller’s experiment provided evidence for the theory of………

3. Sequence of substances appearing during the origin of life would have been.

• Amino acids, ammonia, phosphates, nucleic acid
• Ammonia, amino acids, proteins, nucleic acids
• Nucleotides, amino acids, nucleic acids, enzymes
• Enzymes, amino acids, proteins, nucleic acids.

Answer:
1. a – electrodes
b- mixture of gases (CH₄, NH₃, H₂, H₂O)
c – cold water
d – vacuum pump

2. Organic evolution (chemical evolution)

3. ii) Ammonia, amino acids, proteins, nucleic acids.

Question 3.
A list of human ancestry is given. Pick the correct ancestor from the table.
Neanderthal man
Java man
Australopithecus
Cro-magnon man
Dryopithecus
Homo habilus

1. First man ape
2. The stone tool maker
3. Buried their dead.
4. User of fire for hunting, defence and cooking.
5. Hunter with domesticated dog and did cave paintings.
6. Pre-man

Answer:

1. Australopithecus
2. Homo habilus
3. Neanderthal man
4. Java man
5. Cro-magnon man
6. Dryopithecus

Question 4.
Briefly describe about the evolution of Man.
Answer:
1. Dryopithecus and Ramapithecus: were hairy and walked like gorillas and chimpanzees.

2. Ramapithecus: was more man-like while

3. Dryopithecus: was more ape-like.

4. Australopithecines: They hunted with stone weapons and ate fruit… They did not eat meat.

5. Homo erectus: Their brain capacity is around 900cc. They ate meat.

6. Neanderthal man: with a brain size of 1400cc lived in near east and central Asia

7. Homo sapiens: arose in Africa. The cave art developed about 18,000 years ago and agriculture around 10,000 years back.

Question 5.
Match the following

Answer:

Plus Two Zoology Evolution NCERT Questions and Answers

Question 1.
Attempt giving a clear definition of the term species
Answer:
A species is a group of similar individuals differing from the members of other species which interbred freely and relatively stable. Species is the smallest of classification.

Question 2.
Try to trace various components of human evolution (Hint: brain size and funct skeletal structure, dietary preference, etc.).
Answer:
Changes involved in human evolution are as follows

• Flattening of face
•  Reduction in body hair
• Development of curves in the vertebral column for erect posture.
• Bipedal locomotion, arms are shorter than legs
• Increase in brain size and intelligence
• Start eating cooked food.

Question 3.
List 10 modern-day animals and from internet resources link it to a corresponding fossil.
Answer:
Different birds-Archaeopteryx.

Question 4.
Describe one example of adaptive radiation.
Answer:
Darwin’s finches of Qalapago island exhibiting a variety of beaks.

Question 5.
Can we call human evolution as adaptive radiation?
Answer:
No, because in human evolution, brain size, skeletal structure, dietary preference and social and cultural evolution occured while in adaptive radiation, the origin, basic structure and the devleopment of the organs remain same only morphological changes occurs.

Plus Two Zoology Evolution Multiple Choice Questions and Answers

Question 1.
‘Continuity of germplasm’ theory was given by
(a) Hugo de Vries
(b) Weismann
(c) Darwin
(d) Lamarck
Answer:
(b) Weismann

Question 2.
‘Hot dilute soup’ was given by
(a) Oparin
(b) Haldane
(c) Urey
(d) None of these
Answer:
(b) Haldane

Question 3.
Which one of the following theories was proposed by Weismann?
(a) Law of inheritance
(b) Theory of inheritance of acquired characters
(c) Theory of natural selection
(d) Theory of germplasm
Answer:
(d) Theory of germplasm

Question 4.
Coacervatesare
(a) protobionts having polysaccharide, protein, and H₂O
(b) protein aggregate
(c) protein and lipid aggregates
(d) None of the above
Answer:
(a) protobionts having polysaccharide, protein, and H₂O

Question 5.
The idea that the life originates from pre-existing life is referred as
(a) biogenesis theory
(b) special creation theory
(c) abiogenesis theory
(d) extraterrestrial theory
Answer:
(a) biogenesis theory

Question 6.
Synthesis of amino acids to prove that amino acids were formed in primitive ocean was experimentally proved
(a) Oparin
(b) Haldane
(c) Sydney fox
(d) Stanley Miller
Answer:
(d) Stanley Miller

Question 7.
The abiogenesis occurred about how many billion years ago?
(a) 1.2 billion
(b) 1.5 billion
(c) 2.5 billion
(d) 3.5 billion
Answer:
(d) 3.5 billion

Question 8.
Pasteur and Koch are related to
(a) discovery of nucleic acids (DNA and RNA)
(b) discovery of ultracentrifuge
(c) germ theory of disease
(d) gene splicing
Answer:
(c) germ theory of disease

Question 9.
Wings of insects and birds are
(a) analogous
(b) homologous
(c) vestigial
(d) atavism
Answer:
(a) analogous

Question 10.
Convergent evolution is shown by
(a) homologous organ
(b) analogous organ
(c) vestigial organ
(d) All of these
Answer:
(b) analogous organ

Question 11.
Which one of the following is not a vestigial structure in Homo sapiens?
(a) Third molar
(b) Epiglottis
(c) Plica semilunaris
(d) Pyramidalis muscle
Answer:
(b) Epiglottis

Question 12.
Which of the following presumably possesses a cranial capacity larger than modem man?
(a) Neanderthal man
(b) Peking man
(c) Australopithecus
(d) Cromagnon man
Answer:
(d) Cromagnon man

Question 13.
The gas mixture used by Miller in his experiment comprised
(a) CH₄,C0₂,N₂,H₂O
(b) NH₃,C0₂,H₂O, N₂
(c) CH₂,NH₃,N₂,H₂O
(d) CH₄,NH₃,H₂,H₂O
Answer:
(d) CH₄,NH₃,H₂,H₂O

Question 14.
The Mesozoic era is also called as
(a) the golden age of the amphibians
(b) the golden age of the reptiles
(c) the golden age of the mammals
(d) the golden age of the birds
Answer:
(b) the golden age of the reptiles

Question 15.
Darwin travelled in which of the following ship?
(a) HNS Eagle
(b) D Matrica
(c) H M S Beagle
(d) Titanic
Answer:
(c) H M S Beagle

Question 16.
There are two opposing views about origin of Modem man. According to one view, Homo erectus in Asia were the ancestors of modem man. A study of variations of DNA however suggested African origin of modem man. What kind of observation on DNA variation could suggest this?
(a) Greater variation in Africa than in Asia.
(b) Variation only in Asia and no variation in Africa
(c) Greater variation in Asia than in Africa
(d) Similar variation in Africa and Asia
Answer:
(c) Greater variation in Asia than in Africa

Question 17.
Big bang theory is connected with
(a) origin of earth
(b) origin of universe
(c) origin of moon
(d) origin of life
Answer:
(b) origin of universe

Question 18.
The primitive earth contains
(a) oxygen, methane, carbon dioxide, and ammonia
(b) Water vapour, methane, oxygen, and ammonia
(c) methane, carbon dioxide an ammonia
(d) Water vapour, methane, carbon dioxide, and ammonia
Answer:
(d) Water vapour, methane, carbon dioxide, and ammonia

Question 19.
The first form of life could have come from pre-existing non-living organic molecules like RNA, protein. This was proposed by
(a) Oparin and Haldane
(b) Charles Darwin
(c) Louis Pasteur
(d) Alfred Wallace
Answer:
(a) Alfred Wallace

Question 20.
The spark discharge apparatus that was used by millercontains
(a) CH₄, O₂, H₂, NH₃ and water vapaur
(b) CH₄, O₂, NH₃ and water vapaur
(c) CH₄, O₂, NH_3, and H₂
(d) CH₄, H₂, NH₃ and water vapaur
Answer:
(d) CH₄, H₂, NH₃ and water vapaur

Question 21.
The first non-cellular forms of life could have originated
(a) 3000 mya
(b) 2000 mya
(c) 2bya
(d) 4bya
Answer:
(a) 3000 mya

Question 22.
The type of evolution leads to the formation of analogous organs
(a) convergent evolution
(b) divergent evolution
(c) microevolution
(d) chemical evolution
Answer:
(a) convergent evolution

Question 23.
The white winged moth survived and the dark-coloured moth were picked out by predators before industrial revolution in England. It supports the theory that proposed by
(a) Lamark
(b) Darwin
(c) Hugo De Vries
(d) Oparin
Answer:
(b) Darwin

Question 24.
In Galapogos island the original seed-eating features of finches of birds changed and become insectivorous and vegetarian finches. This process of evolution radiating to other areas of geography and results
(a) more than two types of beaks in finches
(b) all finches of islands subjected to adaptive radiation
(c) all finches of islands subjected to discontinuous variation
(d) adaptive radiation not leads to evolution
Answer:
(b) all finches of islands subjected to adaptive radiation

Question 25.
A colony of bacteria growing on a given medium utilise a feed component but change in the medium composition affect the population and can survive under the new conditions. This is come under the theory of
(a) Lamark
(b) Darwin
(c) Louis Pasteur
(d) Malthus
Answer:
(b) Darwin

Plus Two Zoology Evolution SCERT Sample Questions and Answers

Question 1.
Arrange the following primates in correct sequence of evolution to man.

1. Dryopethicus
2. Homo erectus
3. Homo habilis
4. Neanderthal man (2)

Answer:
Dryopithecus – Homo habilis – Homo erectus – Neanderthal man.

Question 2.
Carefully read the following statement and answer the questions. “A population remain constant and stable in its allele frequency from generation to generation. Such population shows genetic equilibrium’.

1. Name the underlying principle in the above statement. (1)
2. Name any two factors which affect genetic equilibrium. (1)

Answer:

1. Hardey – Weinberg Principle
2. Mutation, Natural Selection Migration, Genetic drift.

Students can Download Chapter 4 Molecular Basis of Inheritance Questions and Answers, Plus Two Zoology Chapter Wise Questions and Answers helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala Plus Two Zoology Chapter Wise Questions and Answers Chapter 4 Molecular Basis of Inheritance

Plus Two Zoology Molecular Basis of Inheritance One Mark Questions and Answers

Question 1.
The process of copying genetic information from one strand of the DNA into RNA termed as
(a) translation
(b) transamination
(c) replication
(d) transcription
Answer:
(d) transcription

Question 2.
An enzyme that uses viral RNA as template for the synthesis of DNA is
(a) RNA polymerase
(b) reverse transcriptase
(c) viral nuclease
(d) RNA replicase
Answer:
(b) reverse transcriptase

Question 3.
The sequence of structural gene in Lac operon concept is
(a) Lac A, Lac Y, Lac Z
(b) Lac A, Lac Z, Lac Y
(c) Lac Y, Lac Z, Lac A
(d) LacZ, Lac Y, Lac A
Answer:
(d) LacZ, Lac Y, Lac A

Question 4.
During transcription, the nucleotide sequence of the DNA stand that is being coded is ATACG, then the nucleotide sequence in the mRNA would be
(a) TATGC
(b) TCTGG
(c) UAUGC
(d) UATGG
Answer:
(c) UAUGC

Question 5.
Anticodon is base triplet on
(a) mRNA complementary to base sequence on rRNA
(b) mRNA complementary to base sequence on tRNA
(c) tRNA complementary to base sequence on rRNA
(d) tRNA complementary to base sequence on mRNA
Answer:
(d) tRNA complementary to base sequence on mRNA

Question 6.
There is a murder, which shocked the entire town. The dead body contain the blood smear of other person. The police suspected two persons. Name the method used to identify the murderer.
Answer:
DNA finger printing

Question 7.
In DNA molecule a nitrogenous base bonded with pentose sugar molecule through a………Bond.
Answer:
Phosphodiester bond.

Question 8.
Histone proteins are………Charged molecule.
Answer:
Positively Charged

Question 9.
Histone octamer bind to DNA to form………..
Answer:
Nucleosomes

Question 10.
The chromosomes are seen on which stage of the cell cycle.
Answer:
Metaphase

Question 11.
The virus which infects the bacteria are called…………
Answer:
Bacteriophage

Question 12.
Histones are the proteins found associated with eucaryotic DNA. Name the two Amino acids which is found in greater quantity in Histones.
Answer:
Lysines and Arginines

Question 13.
Pick the genetic material in human beings (RNA, mRN.tRNA, DNA)
Answer:
DNA

Question 14.
The DNA synthesis in leading strand is
(a) continuous
(b) not as single strand
(c) discontinuous
(d) as Okazaki fragments
Answer:
(a) Continuous.

Question 15.
Expand the following
mRNA = messenger RNA
tRNA = ……………….
rRNA = Ribosomal RNA
hnRNA = ………………
Answer:
tRNA = transfer RNA
hnRNA = heterogenous nuclear RNA

Question 16.
Pick the initiation codon from the triplets codons given below. AAA, UGA.AUG, GUA
Answer:
AUG

Question 17.
From the following triplet codes find out the stop codon (GAU, UCU, UAG, UGG)
Answer:
UAG

Question 18.
A DNA molecule in which both strands have radioactive thymidine is allowed to duplicate in an environment containing non-radioactive thymidine. What will be the correct number of DNA molecule that contain some radioactive thymidine after 3 duplications?
Answer:
Two DNA molecules

Question 19.
A change in a sequence of DNA occurs so that the mRNA codon reads AUC rather than AUU. Both of these code for the amino acid isoleucine. Argue that this is not a mutation.
Answer:
If one defines a mutation as a change in genetic material resulting in a different phenotypic expression. Hence this is not a mutation.

Question 20.
Histones are the proteins found associated with eucaryotic DNA. Name the two Amino acids which is found in greater quantity in Histones.
Answer:
Lysines and Arginines

Plus Two Zoology Molecular Basis of Inheritance Two Mark Questions and Answers

Question 1.
To solve a dispute of parentage, the court put an order to conduct a test to prove the father of the child. Name the test used. Procedure of the test is given below, complete it.

1. Isolation of DNA.
2. DNA is cut using restriction endonuclease.
3. ……………
4. …………..
5. hybridization using VNTR probe
6. ………….

Answer:
Name of the test is DNA finger printing. The procedure is

1. Isolation of DNA.
2. DNA is cut using restriction endonuclease.
3. Separation of DNA fragments by electrophoresis.
4. Blotting of separated DNA fragments on nitrocellulose.
5. hybridization using VNTR probe
6. Detection of hybridised DNA fragments by autoradiography.

Question 2.
DNA finger printing is a technique in molecular biology. Arrange the following steps in sequence. Blotting of DNA fragment to nitro cellulose. Digestion of DNA by restriction endonuclease. Deletion of DNA by restriction endonuclease. Isolation of DNA, separation of DNA fragments by electrophoresis.
Answer:

1. Isolation of DNA
2. Digestion of DNA by restriction endonuclease.
3. Separation of DNA fragments by electrophoresis.
4. Blotting of DNA fragment to nitrocellulose.
5. Deletion of hybridised DNA by autoradiography.

Question 3.
Match the columns A, B, and C.

Answer:

Question 4.

Process of Transcription in Bacteria is shown. Identify any two differences, found in eukaryotec transcription.
Answer:
1. There are 3 RNA polymerases, namely RNA Polymerase I – Transcribes rRNAs . RNA Polymerase II – Transcribes hn RNA (precursor of mRNA) RNA Polymerase III – TranscribestRNA, 5srRNA, SnRNAs.

2. There are complexities like splicing, capping, tailing, etc. in eukaryotic transcription.

Question 5.
Identify the following and differentiate them.

1. AUG
2. UGA

Answer:

1. AUG – Codes for methionine and it acts as initiator codon.
2. UGA – Does not code for any amino acids and acts as stop codon.

Question 6.
Repetitive sequences in a DNA molecule are of no importance. Do you agree?
Answer:
Repetitive DNA is a small stretch of DNA repeated many times. They show high degree of polymorphism and form the basis of DNA finger printing.

Question 7.

Observe the diagram and identify A & B.
Answer:

1. Histone octamer
2. DNA

Question 8.
Match the following experiments and conclusions with respective worker.

Answer:

Question 9.

Name the process (a) and (b).
Answer:
a – Transcription,
b-Translation

Question 10.
In bacteria, three major types of RNAs are needed for the synthesis of protein.

1. List them and mention their functions.
2. What are the three steps in transcription in bacteria

Answer:

1. List them and mention their functions:

• mRNA – It provides the template
• tRNA – It brings amino acids and reads the genetic code.
• rRNA – It plays structural and catalytic role during translation.

2. three steps in transcription in bacteria:

• Initiation
• Elongation
• Termination

Question 11.
State whether the following statements are true or false. If false rewrite them by changing the word understand.

1. Double helical of DNA was proposed by Jacob and Monod.
2. Sugar present in RNA is deoxyribose
3. Introns are the coding sequences of an eukaryote gene.
4. The common method of DNA replication is conservative.

Answer:
All are false.

1. Watson and Crick
2. Ribose
3. Exons
4. Semi conservative

Question 12.
The transcription is usually taking place from DNA to RNA. Can you explain any instance where transcription takes place in reverse order?
Answer:
Yes. In some viruses, it takes place by reverse transcription.

Question 13.
In the medium where E. Coli was growing, lactose was added, which induced the lac operon. Why does lac operon shut down after sometime addition of lactose in the medium?
Answer:
Lac operon is shut down after some times when the added lactose is utilized from the medium. It is be-cause the repressor protein binds to the operator region of the operon and prevent RNA polymerase from transcribing the operon.

Question 14.
While an mRNA strand is being translated in the ribosome subunit, the triplets in sequence were UAC and UAG. One of them codes for tyrosine. What is the significance of the other? Pick out the codon and specify.
Answer:
UAG acts as terminator codon thus leads to the termination of polypeptide chain. It does not specify any amino acid.

Question 15.
What are structural genes? Name the three structural genes present in the lac operon of Escherichia coil?
Answer:
Structural genes are those genes which actually synthesise mRNAs. The lac operon of Escherichia coli contains three structural genes (z, y and a)

Question 16.
In a classroom discussion your classmate says that the RNA is more stable than DNA. Do you agree with it. Explain the advantage of DNA over RNA.
Answer:
No. DNA is more stable
While DNA contains deoxyribose, RNA contains ribose (in deoxyribose there is no hydroxyl group attached to the pentose ring in the 2 position). These hydroxyl groups make RNA less stable than DNA because it is more prone to hydrolysis. DNA have

1. Replication
2. Chemically and structurally stable
3. Obey Mendelian Characters

Question 17.

1. Mention any four goals of Human Genome Project.
2. Name two methodologies involved in it.

Answer:
1. Identify 20000-25000 genes in human DNA., determine 3 billion base pairs, store information as database, improve tool for data analysis, transfer related technologies to other sectors such as industries.

2. Expressed Sequence Tag Sequence Annotation.

Question 18.
Explain the transforming principle and its experiment.
Answer:
Mouse + live S strain = mouse died Mouse + live R strain = mouse alive Mouse + heat-killed S strain = mouse alive Mouse + heat-killed S strain along with R strain = mouse died.

(certain factors from heat-killed S strain transforms non-virulent R strain to become S strain ie, transfer of genetic material)

Question 19.
The regulation of gene expression happened at various levels in eukaryotes. Point out the levels of gene expression.
Answer:

• Transcriptional level
• Processing level
• Transporting mRNA
• Translational level.

Question 20.
Chromatin is a lengthy molecule. How is it compactly packed in nucleus?
Answer:
Nucleosome Histones are organised to form a unit of eight molecules called as histone octamer. The negatively charged DNA is wrapped around the positively charged histone octamerto form a structure called Nucleosome.

Question 21.
Observe the figure and answerthe following.

1. Name the biomolecule
2. Explain the function of this molecule.

Answer:

1. tRNA
2. Activation and transport of amino acid Ribosome

Question 22.
Identify figure and answer the following.

1. Name the experiment.
2. Briefly explain this experiments.

Answer:

1. Meselson and Stahl Experiment
2. They transferred the cells into a medium with normal ¹⁴NH₄Cl and took samples at various definite time intervals as the cells multiplied, and extracted the DNA that remained as double stranded helices.

The DNA that was extracted from the culture one generation after the transfer from ¹⁵N to ¹⁴N medium [E coil divides in 20 minutes] had a hybrid DNA.

DNA extracted from the culture after another generation [that is after 40 minutes, II generation] was composed of equal amounts of this hybrid DNA and of ‘light’ DNA.

Plus Two Zoology Molecular Basis of Inheritance Three Mark Questions and Answers

Question 1.
Both RNA and DNA are considered as genetic materials.

1. What are the main criteria for a molecule to act as genetic material?
2. Why DNA is considered as a better genetic material than RNA?
3. Why RNA viruses mutate and evolve faster than DNA virus?

Answer:

1. Main criteria for a molecule to act as genetic material:

• Able to generate replica
• Chemically and structurally stable
• Provide scope for slow mutation, required for evolution.
• Able to express itself in the form of ‘Mendelian characters’.

2. RNA, being catalytic, is chemically more reactive and less stable than DNA. Therefore DNA is a better genetic material as it is less reactive and structurally more stable.

3. RNA is unstable than DNA, so mutate at a faster rate. Viruses having RNA genome, with shorter life span mutate and evolve faster.

Question 2.
The sequence of nitrogen bases on one of the polynucleotide chains of a DNA strand is given below.

1. Write the complimentary strand of this polynucleotide chain.
2. Write the sequence of mRNA framed from the template strand.
3. Name the process in which mRNA is formed.
4. Name the enzyme that catalyses the formation of mRNA

Answer:

1. TAC GGC GAT TTT
2. UAC GGC GAU UUU
3. Transcription
4. RNA Polymerase

Question 3.
The most widely accepted scheme for replication was proposed by Watson & Crick.

1. Name the scheme of replication.
2. Who given the experimental proof forthis?
3. Name the medium used.

Answer:

1. Semi conservative DNA replication
2. Messelson and Stahl
3. Medium containing ¹⁵NH₄Cl and normal ¹⁴NH₄Cl. CsCl used for centrifugation.

Question 4.

1. Identify the representative diagram.
2. Mention its application and future challenge (anyone).
3. Name the methods involved in it.

Answer:

1. Human genome.project (HGP)

2. Application – They can study all the genes in a genome.
Future challenge – Requires expertise and creativity of thousands of scientists of various disciplines.

3. Name the methods involved in it:

• Expressed Sequence Tags (ESTs)
• SequenceAnnotation

Question 5.
The schematic representation of the Lac operon is given below:

1. Label a, b, c, d.
2. Name the inducer in this operon.
3. Write any two other operon.

Answer:

1. a – P b – z, c – y, d – a
2. Lactose
3. Trp operon, ara operon, etc.

Question 6.
In eukaryotes, RNA polymerase II transcribes precursor of mRNA, called hnRNA.

1. What is the full form of hnRNA?
2. Describe the additional processings takes place in an hnRNA to become mRNA.
3. What is gene splicing?

Answer:
1. Heterogeneous nuclear RNA

2. The additional processings takes place in an hnRNA to become mRNA:

i. Capping:
It is the addition of nucleotide (methyl guanosine triphosphate) at 5¹ – end of hnRNA.

ii. Tailing:
It is the addition of adenylate residues at 3¹ – end.

3. Gene splicing is the removal of non-functional introns and joining of exons in a defined order.

Question 7.

The above pictures are the DNA finger prints of a child and suspected persons as the father of the child.

1. Out of the suspected persons, find the true father of the child.
2. How will you identify the father?
3. What is the principle behind this?

Answer:
1. C may be the true father.

2. As the bands presented is the finger print match between child and person C. It denotes that hereditary materials are more or less common in these two bands. Usually a child comes 50% of hereditary materials from his father. So ‘C’ may be the father of the child.

3. Principle behind it is VNTRs. Southern blotting using variable number of Tandem Repeats (VNTR) as a probe.

Question 8.
One of the salient features of genetic code is codon is triplet and 61 codons code for amino acids and 3 codons are stop codons. Make a list of other salient features of genetic code.
Answer:
1. Genetic code is unambiguous and specific:
A codon always specifies the same aminoacid, it cannot code for more than one amino acid.

2. Genetic code is deoenerate:
Some amino acids are coded by more than one codon.

3. Genetic code is universal:
Each codon of it specifies or codes for the same kind of amino acid in all organisms. (Eg. UUU-phenyl alanine).

4. Genetic code is polarised:
In specifying a particular polypeptide, the genetic code has a definite initiation codon and a terminal codon.

Question 9.

The diagram of a tRNA the adapter molecule is given.

1. Identify the main parts and their role.
2. What you mean by aminoacylation of tRNA?
3. What is the indication of end of translation?

Answer:

1. main parts and their role:

• Anticodon loop – It has been complementary to the code.
• Amino acid acceptor end. It binds to amino acids.

2. Activation of amino acids in presence of ATP and linking to tRNA is called aminoacylation or charging of tRNA.

3. At the end of translation, a release factor binds to the stop codon, to terminate translation and release polypeptide from ribosome.

Question 10.

Diagram of a polynucleotide is given.

1. Identify the 3 components of a nucleotide.
2. Name the purines.
3. Mention the types of linkage present in a polynucleotide.

Answer:

1. 3 components of a nucleotide:

• A nitrogen base
• A pentose sugar (Ribose/ Deoxyribose)
• Phosphate group

2. Adenine and Guanine

3. types of linkage present in a polynucleotide:

• N-glycosidic linkage
• Phosphoester linkage
• Phosphodiester linkage

Question 11.
DNA finger printing is widely used in forensic application. Some terms related to DNA finger printing are given. What are they?

1. Repetitive DNA.
2. VNTR
3. PCR

Answer:

1. A small stretch of DNA repeated many times is called repetitive DNA.
2. Variable Number of Tandem Repeats
3. Polymerase chain reaction – Synthesis of multiple copies of DNA of interest.

Question 12.
Look at the figure above depicting lac operon of E.coli.

1. What could be the series of events when an inducer is pre^nt in the medium in which E.coli is growing?
2. Name the Inducer.
3. Who introduce operon model.

Answer:

1. Inducer induces the operon by inactivating the repressor, allowing RNA polymerase access to promotor and transcription proceeds.
2. Lactose
3. Jacob and Monad

Question 13.
An mRNA strand has a series of codons out of which three are given below:

• AUG
• UUU
• UAG

1. What will these codons be translated into?
2. What are the DNA codons that would have transcribed these RNA codons?

Answer:
1. These codons be translated into:

• AUG signals the synthesis of polypeptide (start signal) and codes for the amino acid methionine.
• UUU codes for phenylalanine.
• UAG do not specify any amino acid and hence is called nonsense codon. It signals the termination of polypeptide chain (stop signal).

2. TACAAAATC.

Question 14.
The quest for finding out the complete DNA sequence of human genome lead to a mega project called HGP.

1. Expand HGP.
2. In which area of biology HGP is closely associated?
3. Mention any four important goals of HGP.

Answer:

1. Human Genome Project (HGP)

2. Bioinformatics

3. The important goals of HGP are

• Identify all the genes (20,000-25,000) in human DNA.
• Determine the sequences of the 3 billion chemical base pairs that make up human DNA.
• Store this information in databases.
• Improve tools for data analysis.
• Transfer related technologies to other sectors, like industries.
• Address the ethical, legal, and social issues (ELSI) that may arise from the project.

Question 15.
Complete the flow chart of the steps involved in DNA fingerprinting.

Answer:

1. Digestion of DNA by restriction endonuclease
2. Blotting of separated DNA fragments to synthetic membranes (nitrocellulose)
3. Hybridisation using VNTR probe.

Question 16.
Identify the figure and answer the following.

Name a, b and c

Answer:
a. Promoter
b. Structural Gene
c. Terminator

Question 17.
Name the process involved in the synthesis of protein from mRNA. Explain the process.
Answer:
The activation of amino acids with ATP and linked to tRNA- a process commonly called as charging of tRNA or aminoacylation of tRNA

bF or initiation, the ribosome binds to the mRNA at the start codon (AUG) that is recognised only by the initiator tRNA.

In elongation, amino acid linked to tRNA. and bind to the codon in mRNA by forming complementary base pairs with the tRNA anticodon.

The ribosome moves from codon to codon along the mRNA. Amino acids are added one by one and translated into Polypeptide.

At the end, a release factor binds to the stop codon, terminating translation and releasing the complete polypeptide from the ribosome.

Question 18.
Observe the figure and complete table 1 with name .of gene and table 2 with enzymes produced by structural gene.

Answer:

Answer:

Question 19.
In a classroom discussion your classmate says that the RNA is more stable than DNA. Do you agree with it. Explain the advantage of DNA over RNA.
Answer:
No. DNA is more stable
While DNA contains deoxyribose, RNA contains ribose (in deoxyribose there is no hydroxyl group attached to the pentose ring in the 2’ position). These hydroxyl groups make RNA less stable than DNA because it is more prone to hydrolysis. DNA have

1. Replication
2. Chemically and structurally stable
3. Obey Mendelian Characters

Plus Two Zoology Molecular Basis of Inheritance NCERT Questions and Answers

Question 1.
If the sequence of coding strange in a transcription unit is written as follows:
5’-ATGCATGCATGCATGCATGCATGCATGCATGC-3’ Write down the sequence of mRNA.
Answer:
The sequence of template strand will be
3’-TACGTACGTACGTACGTACGTACGTACGTACG-5’

Thus, the sequence of mRNA will be
5’-AUGCAAUGCAAUGCAAUGCAAUGCAAUGC

Question 2.
Describe In the medium where E. Coli was growing, lactose was added, which induced the lac operon. Then why does lac operon shut down after some time after addition of lactose in the medium?
Answer:
Lac operon is shut down after some times when the added lactose is utilised from the medium. It is because the repressor protein binds to the operator region of the operon and prevent RNA polymerase from transcribing the operon.

Question 3.
Explain (in one or two lines) the function of following:

1. Promoter
2. tRNA
3. Exons.

Answer:
1. Promoter:
It acts as an initiation signal which function as recognition centre for RNA – polymerase provided the operator gene is switched on.

2. tRNA:
It acts as an adapter molecule which transfers amino acids to ribosomes for synthesis of polypeptides.

3. Exons:
These are coding sequences or expressed sequences in an eukaryotic gene. The exon sequences appear in mature or processed RNA.

Question 4.
Briefly describe the following:

1. Transcription
2. Polymorphism
3. Translation
4. Bioinformatics

Answer:

1. Transcription is the process of creating a RNA copy of a DNA sequence.
2. When different types of phenotype occur in the same species the situation is called polymorphism.

Plus Two Zoology Molecular Basis of Inheritance Multiple Choice Questions and Answers

Question 1.
Select the two correct statements out of the four (l-IV) given below about Lac operon.
I. Glucose or galactose may bind with the repressor and inactivate it.
II. in the absence of lactose the repressor binds with the operator region
III. The z-gene codes for region
IV. This was elucidated by Francois Jacob and Jacques Monad
The correct statement are:
(a) II and III
(b) I and III
(c) II and IV
(d) I and II
Answer:
(c) II and IV

Question 2.
In the Lac operon system, beta-galactosidase is coded by
(a) a-gene
(b) i-gene
(c) l-gene
(d) z-gene
Answer:
(d) z-gene

Question 3.
Match the codons with their respective amino acids and choose the correct answer.

Answer:
(a) 3 4 1 5 2

Question 4.
What is antisense technology?
(a) A cell displaying a foreign antigen used for synthesis of antigens
(b) Production of somaclonal variants in tissue cultures
(c) When a piece of RNA that is complementary in sequence is used to stop expression of a specific gene
(d) RNA polymerase producing DNA
Answer:
(c) When a piece of RNA that is complementary in sequence is used to stop expression of a specific gene

Question 5.
An enzyme that uses viral RNA as template for the synthesis of DNA is
(a) RNA polymerase
(b) reverse transcriptase
(c) viral nuclease
(d) RNAreplicase
Answer:
(b) reverse transcriptase

Question 6.
During translation initiation in prokaryotes, a GTP molecule is needed in
(a) association of 30S, mRNA with formyl-met tRNA
(b) association of 50S subunit of ribosome with initiation complex
(c) formation of formyl- met- tRNA
(d) binding of 30 subunits of ribosome with mRNA
Answer:
(a) association of 30S, mRNA with formyl-met tRNA

Question 7.
The central dogma of protein synthesis in teminism is
(a) rRNA → DNA → mRNA → Protein
(b) DNA → gRNA → mRNA → Protein
(c) DNA → DNA → mRNA → Protein
(d) mRNA →  gRNA →  DNA →  Protein
Answer:
(a) rRNA → DNA → mRNA→ Protein

Question 8.
Which of the following groups of codons codes for amino acid serine?
(a) CUC, CUC, CUAandCUG
(b) UAU, UAC, UGU, and UGC
(c) UCU, UCC, UCA, and UCG
(d) GUU, GUC, GCU, and GCC
Answer:
(c) UCU, UCC, UCA, and UCG

Question 9.
Jacob and Monod studied lactose metabolism in E.coli and proposed operon concept, applicable for
(a) all prokaryotes
(b) all prokaryotes and some eukaryotes
(c) all prokaryotes and all eukaryotes
(d) all prokaryotes and some protozoans
Answer:
(a) all prokaryotes

Question 10.
The sequence of nitrogen bases in a particulars region of the non-coding stand of a DNA molecule was found to be CAT GTTTAT CGC. What would be the sequence of nitrogen bases in the mRNA that is synthesized the corresponding region of the coding strand in that DNA?
(a) GUACAAAUAGCG
(b) GTA CAAATA GCC
(c) CAU GUU UAU CGC
(d) CAAGAATAU GCC
Answer:
(c) CAU GUU UAU CGC

Question 11.
The process of reverse transcription was brought to light by the work of
(a) Geroge Beadle and Edward Tatum
(b) Garrod
(c) HMTemin and D Baltimore
(d) RW Holley and Grover
(e) Marashall and W Nirenberg
Answer:
(c) HMTemin and D Baltimore

Question 12.
Dr. Khurana and his colleagues synthesized an RNA molecule with repeating sequence of UGN bases (UG UG UG UG UG UG). It produced a tetrapeptide with alternating sequence of cysteine and valine. It proves that codons for cysteine and valine is
(a) UGU and GUU
(b) UGUandGUG
(c) UUG and GGU
(d) GUGandUGU
(e) GUU and UGU
Answer:
(a) UGU and GUU

Question 13.
Degeneracy of genetic codes is due to
(a) functional 61 codons and 20 amino acids
(b) functional 64 codons and 20 amino acids
(c) functional 20 codons and 20 amino acids
(d) functional 20 codons and 61 amino acids
Answer:
(a) functional 61 codons and 20 amino acids

Question 14.
A single amino acid is often coded by more than one triplet code. In most of the cases the first two bases are the same but the third base is different. This feature of the genetic codes is called
(a) universality
(b) non-overlapping and commaless
(c) redundancy and degeneracy
(d) non-ambiguity
Answer:
(c) redundancy and degeneracy

Question 15.
Which of the following pairs of chromosomal mutation are most likely to occur when homologous chromosomes are undergoing synapasis?
(a) Deletion and inversion
(b) Duplication and translocation
(c) Deletion and Duplication
(d) Inversion and translocation
Answer:
(c) Deletion and Duplication

Question 16.
Which of the following is generally used for induced mutagenesis in crop plants?
(a) Alpha particles
(b) X-rays
(c) UN (260nm)
(d) Gamma rays (from cobalt 60)
Answer:
(d) Gamma rays (from cobalt 60)

Question 17.
The most likely reason for the development of resistance against pesticides in insect damaging a crop is
(a) random mutations
(b) genetic recombination
(c) directed mutations
(d) acquired heritable changes
Answer:
(a) random mutations

Question 18.
Double helix model of DNA structure was elucidated through X- ray diffraction studies conducted by Watson and Crick with assistance of
(a) Nirenberg and Ochao
(b) Franklin and Wilkins
(c) Har Gobind Khorana
(d) George Gamov
Answer:
(b) Franklin and Wilkins

Question 19.
The approximate distance between the adjacent base pair is
(a) 0.34 nm
(b) 3.4nm
(c) 340 nm
(d) 034nm
Answer:
(a) 0.34 nm

Question 20.
DNA replication takes place in semi-conservative manner was experimentally proved by
(a) Griffith
(b) Messolson and Stahl
(c) Hershey and Chase
(d) McCarthy, Mecloid, and Avery
Answer:
(b) Messolson and Stahl

Question 21.
Okasaki fragments are
(a) short stretch of DNA
(b) long stretch of DNA
(c) joined DNA fragments by ligase
(d) stretches of DNA in leading strand
Answer:
(a) short stretch of DNA

Question 22.
Messolson and Stahl explained the types of DNA molecule formed in different generations as
(a) light DNA
(b) hybrid DNA
(c) heavy DNA
(d) all the above
Answer:
(d) all the above

Question 23.
The base pairs of DNA double helix is given below. Select the suitable mRNA strand that derived from transcription is
3¹-ATTT C C-5¹
5¹-TAAAGG-3¹
(a) UAAAGG
(b) CUUUCC
(c) GAAAGG
(d) CCUUUC
Answer:
(a) UAAAGG

Question 24.
The number of amino acids formed by the various combination of triplet code is
(a) 61
(b) 20
(c) 64
(d) 16
Answer:
(b) 20

Question 25.
RNA processing occurs in
(a) bacteria
(b) viruses
(c) fungi
(d) vi raids
Answer:
(c) fungi

Question 26.
The amino acid serine is coded by
(a) UGC
(b) AGG
(c) UAG
(d) UCC
Answer:
(d) UCC

Question 27.
The significant aspect of reverse transcription is
(a) the flow information from DNA to RNA
(b) the flow information from RNA to DNA
(c) the flow information from RNA to proteins
(d) both a and c
Answer:
(b) the flow information from RNA to DNA

Plus Two Zoology Molecular Basis of Inheritance SCERT Sample Questions and Answers

Question 1.
Read the following and select the correct statement/statements.
(a) 23 s RNA act as a enzyme in prokaryotes.
(b) In prokaryotes DNA is monocistronic
(c) Francis Crick proposed the Central Dogma of Molecular biology.
(d) In Eukaryotes three types of RNA polymerases are present. (an only, a and b, a and c, a and d) (1)
Answer:
(a) 23 s RNA act as a enzyme in prokaryotes
(d) In Eukaryotes three types of RNA polymerases are present.

Question 2.
Study the mRNA segment given below which is ready to be translated into a polypeptide chain and answer the following questions.

1. What is A and B denotes?
2. Write the triplet codon for A and B (1)

Answer:

1. A – start codon B – stop codon
2. A – AUG B – UAA, UGA, UAG

Question 3.
Carefully read the statement given below and correct the digits in the brackets a and b, if it is wrong.

Answer:

1. 2968 instead of 1968
2. No change

Question 4.
Write the functions of the following

1. 5-methyl Guanosine triphosphate (5^m GPPP)
2. DNA Ligase (2)

Answer:

1. act as cap. In capping an unusual nucleotide (methyl guanosine triphosphate) is added to the 5′- end of hnRNA.
2. Joints DNA fragments during replication

Students can Download Chapter 3 Principles of Inheritance and Variation Questions and Answers, Plus Two Zoology Chapter Wise Questions and Answers helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala Plus Two Zoology Chapter Wise Questions and Answers Chapter 3 Principles of Inheritance and Variation

Plus Two Zoology Principles of Inheritance and Variation One Mark Questions and Answers

Question 1.
The 1:2:1 ratio with the pink flower in the F, – generation indicate the phenomenon of
(a) dominance
(b) codominance
(c) incomplete dominance
(d) segregation
Answer:
(c) incomplete dominance

Question 2.
Which of these is not a Mendelian disorder?
(a) Turner’s syndrome
(b) Sickle-cell anaemia
(c) Colourblindness
(d) Haemophilia
Answer:
(a) Turner’s syndrome

Question 3.
Crossing over is advantageous because it brings about
(a) variation
(b) linkage
(c) inbreeding
(d) stability
Answer:
(a) variation

Question 4.
Observe the relationship between first two words and suggest a suitable word to the fourth place.

1. Genetic makeup: Genotype: External appearance: …………
2. Multiple alleles: Blood GP: polygenic trait: ………..

Answer:

1. Phenotype
2. Skin colour is human/Kernel colour is wheat.

Question 5.
Law of segregation is also called law of
(a) probability
(b) purity of gametes
(c) independence of gametes
(d) Punnett hypothesis
Answer:
(b) purity of gametes

Question 6.
Complete it.

1. 44+XXY: Klinifetter’s syndrome: 44+XO………….
2. Monohybrid phenotypic ratio: 3:1, Dihybrid phenotypic ratio:………..

Answer:

1. Turner’s syndrome
2. 9:3:3:1

Question 7.

1. 44A + Xo: Turner’s syndrome, 44A+XXY: …………
2. Man: XX-XY: Birds:…………..

Answer:

1. Klinefelter’s syndrome
2. ZW-ZZ

Question 8.
Blood groups of father, mother, and their two children are given below. Work out the genotypes of each blood group.

1. Father-AB group
2. Mother-O group
3. Daughter – A group
4. Son B-group

Answer:

1. Father – l^A l^B
2. Mother – i i
3. Son-l^Bi
4. daughter l^Ai

Question 9.
Why do certain genes tend to be inherited together in a cell at the time of cell division?
Answer:
Due to linkage.

Question 10.
Pedegree analysis is used to study human genetics. Here individuals and their relationship are represented by symbols. Identify the following symbols.

Answer:
(a) Mating between relatives
(b) Female

Question 11.
Select the correctly matched pair/pairs from the following.
(A) Langdon Down-21^st Trisomy
(B) Sutton and Bovery – Principle of inheritance
(C) Henking-X- body (X- chromosome)
(D) Morgan-Mutation
Answer:
A and C

Question 12.
Name the scientists who proposed chromosomal theory of inheritance?
Answer:
Sutton and Bovery

Question 13.
Select the correct statement or statements from the
following.
(A) Gain of additional chromosome is called aneuploidy.
(B) The affected individual of Turner’s and Klinfelter’s syndrome are fertile.
(C) Increase in the whole set of chromosome in an organism is called polyploidy.
(D) Expected F₂ generation ratio of two genes which do not segregate independently is 9:3:3:1
Answer:
A and C are correct

Question 14.
Character of a genetic disorder is given below. ‘Presence of an additional X chromosome making chromosome number 47 (44 autosomes +XXY)’

1. Identify the disorder
2. Write another one character of this disease?

Answer:

1. Klinfelters syndrome
2. Gynacomastia

Plus Two Zoology Principles of Inheritance and Variation Two Mark Questions and Answers

Question 1.
Substitution of wrong amino acid valine instead of glutamic acid at the 6^th position in glob in chain of Hb cause a disease in man.

1. Name the disease.
2. Draw the amino acid sequence Hb^A peptide and Hb^S peptide.

Answer:

1. Sickle cell Anaemia
2. HbA-

Question 2.
Prepare a table chart showing different human blood groups and its possible genotypes.
Answer:

Question 3.
A man had the following symptoms.
A. short stature,
B. round head
C. puffy face
D. mouth always open with uncontrolled salivation, and
E. mental retardation.
Answer:
(a) Down’s syndrome
(b) It is caused by the trisomy of 21^st pair of chromosome, so that there is a total of 47 chromosomes, instead of the normal 46.

Question 4.
Give one example for each of the following.

1. Inborn error in metabolism.
2. Sex-linked recessive disease.
3. 21^st trisomy.
4. Autosome linked recessive disease.

Answer:

1. Phenylketonuria
2. Haemophilia
3. Down’s syndrome
4. Sickle-cell anaemia

Question 5.
Give reason. Phenylketonuria show accumulation of phenyl alanine in blood.
Answer:
In them, phenyl alanine does not convert into tyrosine, due to the lack of enzyme due to gene mutation.

Question 6.
Observe the crossing of Mirabilis plant and the young ones given below.

1. Name the type of phenomenon of the above crossing?
2. Write the ratio in the F2 Generation.

Answer:

1. Incomplete dominance
2. 1:2:1

Question 7.
In an experiment, Red flowered 4 O’clock plant is crossed with a White-flowered 4 O’clock plant. The F1 generation plant is crossed and produced the F2 generation. The phenotypic and genotypic ratio is 1:2:1. Name the type of inheritance? Explain.
Answer:
Incomplete dominance.

Phenotypic & genotypic ratio is 1:2:1.

Question 8.
The percentage of nucleotide Adenine in DNA isolated from human liver is observed to be 30.7%. What is the expected percentage of T, G and C. Justify?
Answer:
T = 30.7%
G = 19.3%
C = 19.3%
The amount of A is always equals to T. So the percentage of T is expected to be very close to 30.7%. G and C together would make up the remainder or 100 – (30.7 + 30.7) = 38.6, thus the percentage of C and G separately would be expected to equal half of 38.6 or 19.3.

Question 9.
Identify the given symbols used in pedigree charts.

Answer:

1. Sex unspecified
2. Parents above and children below.
3. Male

Question 10.
XXY chromosome pattern is the characteristic feature of a genetic disorder.

1. Write the name of the genetic disorder.
2. Write the phenotypic expressions of this disorder.

Answer:

1. Klinefelter’s syndrome
2. Tall stature with feminised characters like gynaecomastia etc. sterile.

Question 11.
Karyotype of human chromosome compliment is given below. It has some abnormality.

1. Identify the abnormality.
2. Mention any one consequence of this abnormality.

Answer:

1. Trisomy in 21^st Chromosome, having a total of 47 chromosomes instead of the normal 46 leading to Down’s syndrome.
2. It leads to physical, psychomotor and mental retardation.

Question 12.
Copy the table and fill the gap appropriately.

Answer:

Question 13.
A man with blood group A married a woman with B group. They have a son with AB blood group and a daughter with blood group O. Workout the cross and show the possibility of such inheritance.
Answer:
Parents – Father – l^A i – A group
Mother -1^A i – B group
Son – l^A l^B – AB group
Daughter – i i – O group

Question 14.
Identify the type of cross made in flow chart. Explain its significance.

Answer:
Test cross
The progenies of test cross can easily be analysed to predict the genotype of the test organism.

Question 15.
If the frequency of a parental form is higher than 25% in a dihybrid test cross, what does that indicate about the two genes Involved?
Answer:
It indicates that linkage is being shown by two genes of parental forms and they are not exhibiting the phenomenon of independent assortment.

Question 16.
How is a child affected if it has grown from the zygote formed by an XX-egg fertilised by a Y-carrying sperm? What do you call this abnormality?
Answer:
The union of an abnormal XX egg and a normal Y- sperm results in trisomy of sex (X) chromosome. This is a type of sex chromosomal abnormality where the individual has 47 chromosomes (44 + XXY) and the abnormality is called Klinefilter’s syndrome.

Question 17.
Who proposed the chromosomal theory of inheritance? Point out any two similarities in the behaviour of chromosomes and genes.
Answer:
Sutton and Boveri

1. Both factors/ genes and chromosomes occur in pairs in normal diploid cells.
2. Both of them segregate/ separate during game to genesis and enter different gametes, i.e., one member of an allelic pair enters one gamete and the other enters another gamete.

Question 18.
If the frequency of a parental form is higher than 25% in a dihybrid test cross, what does that indicate about the two genes involved?
Answer:
It indicates that linkage is being shown by two genes of parental forms and they are not exhibiting the phenomenon of independent assortment.

Question 19.
In a seminar a student says ABO Blood group is an example for multiple alleles. Are you agree with this? Justify your answer.
Answer:
Yes. ABO blood groups are controlled by the gene I, which has three alleles, namely l^A, l^B, i, which produce six different combinations and six genotypes of the human ABO blood types.

Question 20.
Sickle cell anaemia is a genetic disorder. It is produced by gene mutation. Justify the statement.
Answer:
Sickle cell anaemia is caused by the substitution of glutamic acid by valine, which is due to the single base substitution at the sixth codon of the beta-globin gene from GAG to GUG.

Question 21.
Analyse the figure, find out the error and correct.

Answer:

Question 22.
Fill in the vacant columns.

Answer:

Question 23.
In an experiment, Red flowered 4 O’clock plant is crossed with a White-flowered 4 O’clock plant. The F1 generation plant is crossed and produced the F2 generation. The phenotypic and genotypic ratio is 1:2:1. Name the type of inheritance? Explain.
Answer:
Incomplete dominance.

Phenotypic & genotypic ratio is 1:2:1.

Question 24.

Find out the eukaryotic ribosome. Justify your answer.
Answer:
Eukaryotic ribosome is 80s ribosome, which is composed of a large sub unit 60s and a small subunits 40s.

Question 25.
A cluster of contrasting traits selected and studied by Mendel is given. Categories them into dominant and recessive traits.

Answer:

Question 26.
In a hybridization experiment between tall pea plants and dwarf pea plants, a student observed 100% dominant parental traits in F1 generation and 75% dominant, 25% recessive parental traits are observed in F₂ generation.

1. Identify the type of cross
2. Represent F₂ generation using Punnet square.

Answer:
1. Monohybrid Cross
2.

Question 27.
‘Incomplete dominance is an exception to the principle of dominance’

1. Do you agree with statement? Justify?
2. Explain the principle of dominance.

Answer:
1. Yes, in incomplete dominance intermediate character appears and neither character is completely dominant over the other.

2. In law of dominance, in a heterozygous pair of factors one member of the pair dominates (dominant) the other (recessive).

Question 28.
What is test cross? Design a test cross of the following characters/traits of pea plant.

1. Tall X Dwarf
2. Violet flower X White

Answer:
Crossing of F1 progeny with recessive parent

1. Tt × tt, Offsprings 50% Tt & 50% tt
2. Ww × ww, offsprings 50% – Ww & 50% ww

Question 29.
The amino acid composition of a portion of beta polypeptide chain of haemoglobin is given.

1. Identify the beta chain of sickle cell anaemia patient?
2. Write the difference between the Beta chain of normal haemoglobin and the Beta chain of sickle cell anaemia haemoglobin?

Answer:

1. 1 chain
2. Substitution of glutamic acid by valine at the sixth position of beta chain of Hbs peptide.

Question 30.
A representative figure of an individual affected with a chromosomal/genetic disorder is given.

1. Identify the disorder?
2. Write the genetic reason of this disease?

Answer:

1. Down’s syndrome
2. 21^st trisomy/Non-disjunction of chromosomes during Anaphase I of meiosis.

Question 31.
Compare the chromosomal mechanism of sex determination of the following animals.

1. Drosophila
2. Grasshopper

Answer:
1. XX (female) and XY (male) – Male heterogamety – Male has two sex chromosomes X and Y. Half the sperms with X chromosome and the other Half with a Y chromosome.

2. XX (Female) and XO (male) – Male heterogamety – Male has one Sex chromosome, only X chromosome. Half the sperms with X chromosome and the other half without an X chromosome.

Question 32.
ABO blood group is considered as an example of multiple allelism and Codominance. Explain?
Answer:
ABO blood group is controlled by more than two alleles — l^A, l^B and i. A group l^Al^A, l^A,i, B group—l^Bl^B, l^Bi , AB group l^A, l^B, O group – ii

In AB blood group both l^A and l^B alleles behave as dominant genes, producing both A and B antigens.

Question 33.
In Snapdragon F1 progeny shows pink coloured flowers when a cross in made between red flowered and white flowered plants.

1. What is the genetic reason of this phenomenon?
2. Find out the phenotypic ratio of F2 generation of the same cross.

Answer:

1. Incomplete dominance
2. 1 (Red): 2 (Pink): 1 (White)

Question 34.
Categorize following diseases into a sex-linked recessive disorder and autosome linked recessive disorders. Write the characters of each?

1. Haemophilia
2. Phenyl ketonuria

Answer:

1. Sex-linked recessive, absence of blood clotting due to the lack of a protein.
2. Autosome linked recessive, absence of enzymes that convert phenyl alanine to tyrosine.

Question 35.
Differentiate between Homozygous and heterozygous condition with an example.
Answer:
Alleles of a gene are similar in homozygotes,
E.g. TT for tall, tt for dwarf
Alleles of a gene are dissimilar in heterozygote/ heterozygous.
E.g. Tt heterozygous tall.

Question 36.
Analyse the following statements.
(A) Deletions and insertions of base pair of DNA causes Frame shift mutation.
(B) Chemical and physical factors that induce mutation are referred as polyploidy.
Identify the wrong statement and rectify the mistake
Answer:
(B) is wrong
Chemical or physical factors that induce mutation are referred as mutagens and increase in the whole set of chromosome is called polyploidy.

Question 37.
Is it possible for:

1. Awomanto inherit X chromosome from her father?
2. A man to inherit X chromosome from his father?

Answer:

1. Yes. Father give X to female and Y to male offspring
2. No, Father give X to female and Y to male offspring.

Question 38.
Blood groups of father, mother, and their two children are given below. Work out the genotypes of each blood group.

1. Father – AB group
2. Mother – O group
3. Daughter – A group
4. Son B – group

Answer:

1. Father- l^A l^B,
2. Mother- i i,
3. Son – l^Bi,
4. daughter l^A i

Question 39.
‘Down’s syndrome and Turner’s syndrome are the examples of aneuploidy’. Substantiate.
Answer:
Loss or gain of chromosomes is called aneuploidy Down’s syndrome is 21^st trisomy-total number of chromosome is 47, gain of one chromosomes In Turners syndrome one X chromosome is lost which results in 44 autosomes and one sex chromosomes.

Plus Two Zoology Principles of Inheritance and Variation Three Mark Questions and Answers

Question 1.
In one of his dihybrid crosses, Mendel crossed a true breeding double dominant pea plant with round and yellow seeds with true breeding double recessive plant having wrinkled and green seeds. The phenotypic ratio got was 9:3:3:1. Using checker board, try to find out the genotypic ratio.
Answer:

Phenotypic ratio –

1. Round yellow – 9
2. Round green – 3
3. Wrinkled yellow – 3
4. Wrinkled green -1

Phenotypic ratio – 9 3 3 1
Dihybrid genotypic ratio is 1:2:2:4:1:2:1:2:1

Question 2.
State whether the following statements are true or false. If false, rewrite them by changing the word underlined.

1. A chromosome is mostly made up of RNA.
2. Down’s syndrome is caused by the trisomy of the 10^th chromosome.
3. The somatic cells of females have XX pair of sex chromosome.
4. In a normal dihybrid cross, phenotypic ratio is 9:3:3:1.

Answer:

1. A chromosome is mostly made up of DNA.
2. Down’s syndrome is caused by the trisomy of the 21^st chromosome.
3. The somatic cells of females have XX pair of sex chromosome-True.
4. In a normal dihybrid cross, phenotypic ratio is 9:3:3:1 -True.

Question 3.
Chromosomal mechanism of sex determination involves different types of mechanisms. Three such types are given.
XO type
XY type
ZW type

1. Give example for each type.
2. Differentiate between male heterogamety and female heterogamety.
3. Is the sperm or egg responsible for the sex of the chicks?

Answer:
1. XO type – Grasshopper
XY – Man, Drosophila
ZW – Birds

2. Sex determination mechanism in which males produce two different types of gametes (say X and Y) is called male heterogamety and if female produce two types of gametes (Say Z and W), it is called female heterogamety.

3. In chick, it is the egg which determines the sex. ZW is female and ZZ is male. Z and W are produced by the egg not sperms.

Question 4.
Human ABO blood groups are controlled by the gene l, which has three alleles l^A, l^B and i. Each person possesses any two of the three I gene alleles. Make a table showing the different combinations of these three alleles that are possible in human.
Answer:

Question 5.
Experimental verification of the chromosomal theory of inheritance on Drosophila melanogaster led to discovering the basis for variation that sexual reproduction produced.

1. Name the scientist who formulated chromosome theory of inheritance.
2. Who expanded it by experimental verification?
3. Why did he select Drosophila melanogaster for his studies?

Answer:

1. Sutton and Bovery

2. Thomas Hunt Morgan

3. Drosophila was very suitable for his studies because

• They could be grown on simple synthetic medium.
• Complete life cycle in 2 weeks.
• A single mating could produce a large progeny.
• Male and female are easily distinguishable
• Many hereditary variations can be seen with low power microscope

Question 6.
According to common Mendelian pattern of inheritance, F₁ resembles the dominant parent. But in contrast, there are certain other patterns of inheritance in which F₁ does not resembles either of the parents.

1. Name the pattern of inheritance in which F₁ shows a character in between the two parents.
2. Citing an example write the phenotypic ratio of F₂ in the above cross.
3. Name the pattern of inheritance in which F₁ resembles both parents.

Answer:
1. Incomplete dominance

2. Eg: Flower colour in Snapdragon

Phenotypic ratio -1:2:1

3. Co-dominance.

Question 7.

1. What is Pedigree analysis?
2. Write any two Mendelian disorders in man.
3. Give an example each for Autosomal recessive and autosomal dominant traits.

Answer:

1. Analysis of traits in several generations of a family is called pedigree analysis. It helps to study the family history about inheritance.

2. two Mendelian disorders in man:

• Haemophilia
• Sickle-cell Anemia
• Cystic fibrosis
• Colourblindness

3. Autosomal recessive trait – Sickle cell anemia Autosomal dominant trait – Muscular dystrophy

Question 8.
In one of his dihybrid crosses, Mendel crossed a true breeding double dominant pea plant with round and yellow seeds with true breeding double recessive plant having wrinkled and green seeds. The phenotypic ratio got was 9:3:3:1. Using checker board, try to find out the genotypic ratio.
Answer:

1. Round yellow – 9
2. Round green – 3
3. Wrinkled yellow – 3
4. Wrinkled green -1

Phenotypic ratio – 9 3 3 1
Dihybrid genotypic ratio is 1:2:2:4:1:2:1:2:1

Question 9.
What do you understand by the following symbols of Pedigree analysis?

Answer:
(A) Mating
(B) Mating between relatives
(C) Parents above and children (Two) below, one son and one daughter.

Question 10.
‘In human being father is responsible for the sex of child’. Based on |he knowledge of chromosomal mechanism of sex determination, substantiate this statement?
Answer:
During spermatogenesis, two types of gametes are produced of which 50 percent carry the X- chromosome and the rest 50 percent has Y-chromosome besides the autosomes.

Females produce only one type of ovum with an X- chromosome. In case the ovum fertilises with a sperm carrying X- chromosome the zygote develops into a female (XX) and with Y-chromosome results into a male offspring. Thus the genetic makeup of the sperm that determines the sex of the child

Question 11.
Observe the following pedigree chart

1. What is the indication of symbols □ and ○
2. Some symbols are shaded or darkened why?
3. Write the significance of pedigree chart?

Answer:

1. ○ – Female, □ – Male

2. Affected individuals

3. Pedigree charts are important for examining genetics in family. It can be used to track certain traits in family members through two or more generations of a family.

Question 12.
In a pea plant the gene for yellow seed colour (YY) is dominant to green (yy) and round seed (RR) is dominant to wrinkled (rr). With the help of Punnet square, find out the offspring of F₂ generation of the following cross. Yellow Round seeds x Green wrinkled seeds (Homozygous for both characters)
Answer:

Phenotypic ratio: 9 : 3 : 3 : 1.

Question 13.
Match the columns A with column B.

Answer:

Question 14.
Compare incomplete dominance and co dominance with suitable examples?
Answer:

Plus Two Zoology Principles of Inheritance and Variation NCERT Questions and Answers

Question 1.
Briefly mention the contribution of T.H. Morgan in genetics.
Answer:
Thomas Hunt Morgan put forth chromosome theory of linkage from his work on fruit fly (Drosophila melanogaster). He established the principle of linkage, discovered sex linkage and technique of chromosomal mapping. He wrote a book Theory of gene’ and was awarded Nobel Prize in 1933.

Question 2.
What is pedigree analysis? Suggest how much an analysist can be useful?
Answer:
A record of inheritance of certain traits for two or more generations presented in the form of a diagram or family tree is called pedigree. Analysis of traits in a several generation of a family is called as pedigree analysis. It is employed in case of human beings and domesticated animals.

Importance:
In human genetics, pedigree study provides a strong tool which is utilized to trace the inheritance of a specific trait, abnormality or disease.

It is useful for the genetic counselors to advice in tending couples about the possibility of having children with genetic defects like hemophilia, colour blindness, alkaptonuria, thalassemia, and sickle all anemia.

Question 3.
How is sex determined in human beings?
Answer:
If the zygote is having XX chromosomes in last pair, then it will be female child. If zygote is having XY chromosome then it will be a male child.

Question 4.
A child has blood group O. If the father has blood group A and mother blood group B, work out the genotypes of the parents and the possible genotypes of the other offsprings.
Answer:
The parents of the child will be heterozygous for their blood groups. Therefore, his father with blood group A must-have genotype (l^A l^o) and mother with blood group B must have genotype (l^B l^o).

Question 5.
Explain the following terms with examples:

1. Co-dominance
2. Incomplete dominance

Answer:
1. The alleles which are able to express themselves independently when present together are called co-dominant alleles and this phenomenon is called codominance e.g. AB blood group inheritance in humans.

2. In this phenomenon of the contrasting characters are dominant. The expression of the trait in F1 hybrid is intermediate e.g. pink flowers in peaplant.

Mention the advantages of selecting pea plant for experiment by Mendel. Pea is a annual plant which gives result within a year.

Large number of are produced by pea plant in one generation. Pea plant has short life cy large number of true breeding varities with observable alternative forms trait were available.

Plus Two Zoology Principles of Inheritance and Variation Multiple Choice Questions and Answers

Question 1.
Mating of an organism to a double recessive in order to determine whether it is homozygous or heterozygous for a character under consideration is called
(a) reciprocal cross
(b) test cross
(c) dihybrid cross
(d) back cross
Answer:
(b) test cross

Question 2.
A dihybrid for the traits is crossed with homozygous recessive individual of its type, the phenotypic ratio is
(a) 1 : 2: 1
(b) 3
(c) 1 : 1:1:1
(d) 9:3:3:l
Answer:
(c) 1 : 1:1:1

Question 3.
A dihybrid test cross yielding a result of 1:1:1 ratio is indicative of
(a) four different types of gametes produced by the F1 hybrid
(b) homozygous condition of the F1 -dihybrid
(c) four different types of F1 -generation dihybrids
(d) tour different types of gametes produced by the-parent
Answer:
(a) four different types of gametes produced by the F1 hybrid

Question 4.
When a dihybrid cross is fit into a Punnett square with 16 boxes, the maximum number of different phenotypes available are
(a) 8
(b) 4
(c) 2
(d) 16
Answer:
(b) 4

Question 5.
Cross between unrelated group of organisms is called
(a) hybrid
(b) test cross
(c) hack cross
(d) heterosis
Answer:
(a) hybrid

Question 6.
A pure tall and a pure dwarf plant were crossed to produced offsprings. Offsprings were self crossed, then find out the ratio between true breeding tall to true breeding dwarf?
(a) 1: 1
(b) 3:1
(c) 2:1
(d) 1:2:1
Answer:
(a) 1:1

Question 7.
Genotypic ratio of a monohybrid cross is
(a) 1:2:1
(b) 3:1
(b) 9:3:3:1
(d) !:1:1
Answer:
(a) 1:2:1

Question 8.
Ratio of progeny, when a red coloured heterozygote is crossed with a white coloured plant in which red colour is dominant to white colour
(a) 3:1
(b) 1:1
(c) 1:2:1
(d) 9:3:3:1
Answer:
(b) 1:1

Question 9.
Leaf colour in Mirabilis jalapa is an example of
(a) non-Mendelian inheritance
(b) Mendelian inheritance
(c) chemical inheritance
(d) Both (b) and (c)
Answer:
(a) non-Mendelian inheritance

Question 10.
The F2-generation offspring in a plant showing incomplete dominance, exhibit
(a) variable genotypic and phenotypic ratio
(b) a genotypic ratio of 1:1
(c) a phenotypic ratio of 3: 1
(d) similar phenotypic and genotypic ratio of 1:2:1
Answer:
(d) similar phenotypic and genotypic ratio of 1:2:1

Question 11.
The total number of progeny obtained from a dihybrid cross is 1280 in F2 -generation. How many of them are recombinant type?
(a) 240
(b) 360
(c) 400
(d) 720
Answer:
(c) 400

Question 12.
A test cross is performed
(a) by selfing of F7-generation plants
(b) by selfing of F1 -generation plants
(c) to determine whether F1 -plant is homoygous or heterozygous
(d) between a homozygous dominant and homozygous recessive plant
Answer:
(c) to determine whether F1 -plant is homoygous or heterozygous

Question 13.
Crossing over is advantageous because it brings about
(a) variation
(b) linkage
(c) inbreeding
(d) stability
Answer:
(a) variation

Question 14.
If a plant having yellow or round seeds was crossed with another plant having green and wrinkled seeds then F1 -progeny are in the ratio
(a) 15: 1
(b) 1 15
(c) 1: 13
(d) All yellow and round seeds
Answer:
(d) All yellow and round seeds

Question 15.
When a diploid female plant is crossed with a tetraploid male, the ploidy of endosperm cells in the resulting seed
(a) tetraploidy
(b) pentaploidy
(c) diploidy
(d) triploidy
Answer:
(a) tetraploidy

Question 16.
In certain plant species, red flower colour is incompletely dominant to white flower colour (the heterozygote is pink) and tall stems are completely dominantto dwarf stern. If a tall pink plant (TtRr) is crossed with a tall white plant (TTrr). which one of the following type of plants would be produced in the offsprings
(a) Tall pink and tall white
(b) Dwarf pink and tall red
(c) Dwarf red and tall pink
(d) Tall pink and dwarf white
Answer:
(d) Tall pink and dwarf white

Question 17.
The important events of segregation takes place during
(a) prophase I
(b) anaphase I
(c) prophase II
(d) anaphase II
Answer:
(b) anaphase I

Question 18.
The phenotypic ratio obtained by Mendel in dihybrid cross is
(a) 3:3:1:1
(b) 1:2:1
(c) 9:3:31
(d) 3:1
Answer:
(c) 9:3:31

Question 19.
The unknown genotype of individual is determined by
(a) dihybrid cross
(b) back cross
(c) test cross
(d) monohybrid cross
Answer:
(c) test cross

Question 20.
The studies of incomplete dominance is conducted on
(a) pisum
(b) snapdragon
(c) lathyrus
(d) fruit flies
Answer:
(b) snapdragon

Question 21.
Codominance is shown by the alleles of
(a) l^Ai
(b) l^B i
(c) l^Al^B
(d) ii
Answer:
(c) l^Al^B

Question 22.
The experimental proof for the theory of inheritance was provided by the studies on
(a) pisum
(b) oenothera
(c) lathyrus
(d) fruit flies
Answer:
(d) fruit flies

Question 23.
Gynaecomastia is the case arises by
(a) increase in the number of sex chromosomes
(b) increase in the number of autosomes
(c) increase in the number of autosomes and sex chromosomes
(d) none of the above
Answer:
(a) increase in the number of sex chromosomes

Question 24.
2n-1 is an example of
(a) polyploidy
(b) aneuploidy
(c) euploidy
(d) diploidy
Answer:
(b) aneuploidy

Question 25.
The disease transmitted from father to grandson through daughter in zig-zag manner is an example of
(a) sickle cell anemia
(b) hemophilia
(c) phenyl ketonuria
(d) Turners syndrome
Answer:
(b) hemophilia

Question 26.
Monosomy is represented by the condition of
(a) 2n+1
(b) 2n-1
(c) 2n-2
(d) n-1
Answer:
(b) 2n-1

Plus Two Zoology Principles of Inheritance and Variation SCERT Sample Questions and Answers

Question 1.
A. Carefully read the following symptoms and identify the genetic disorders.

1. Autosomal linked recessive trait where RBC become sickle shaped.
2. Inborn error of metabolism, where phenyl alanine accumulates in blood.
3. Disorderdueto absence of ‘X’ chromosome. (3)

Answer:

1. Sickle cell anaemia
2. Phenyl Ketonuria
3. Turners’ Syndrome

OR

B. Write the contribution of the following biologists in connection with genetics.

1. Henking
2. T.H. Morgan
3. Sutton and Boveri (3)

Answer:
1- Henking- He gave the importance of X body transfer in spermatogenesis of insects

2 – T.H. Morgan – Morgan gave the importance of physical association or linkage of the two genes and coined the term linkage.

3 – Sutton & Boveri – He gave the importance of the pairing and separation of a pair of chromosomes would lead to the segregation of a pair of factors they carried, it is called chromosomal theory of inheritance.

Question 2.
Write the gametes produced from self crossing of genotype RrYy. (2)
Answer:
RY, Ry, rY, ry

Students can Download Chapter 2 Reproductive Health Questions and Answers, Plus Two Zoology Chapter Wise Questions and Answers helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala Plus Two Zoology Chapter Wise Questions and Answers Chapter 2 Reproductive Health

Plus Two Zoology Reproductive Health One Mark Questions and Answers

Question 1.
“Saheli” contraceptive oral pill was developed at:
(a) Department of Biotechnology, New Delhi
(b) CDRI, Lucknow
(c) NEERI, Nagpur
(d) Department of Molecular Biology, Hyderabad
Answer:
(b) CDRI, Lucknow

Question 2.
Most accepted method of contraception in India is:
(a) Use of condoms
(b) Taking oral pills
(c) UseoflUDs
(d) Surgical method
Answer:
(c) Use of lUDs

Question 3.
Select the sexually-transmitted disease:
(a) Syphilis
(b) Hepatitis-B
(c) Genital herpes
(d) All of these
Answer:
(c) Genital herpes

Question 4.
In IVF technique, fusion of ovum and sperm occurs in:
(a) Fallopian tube
(b) Uterus
(c) Vagina
(d) Culture medium
Answer:
(d) Culture medium

Question 5.
Genital herpes is a non-curable STP even if detected earlier. Name two other non-curable STDs.
Answer:
Hepatitis-B, AIDS

Question 6.
Identify the relationship between first and second word, find out the fourth one.

1. Termination of pregnancy: MTP
   Insemination into uterus:………..
2. LNG 20: Hormone releasing IUD
   Lippes loop:……….

Answer:

1. IUI
2. Non medicated IUD

Question 7.
Name two barrier methods used in contraception.
Answer:
Condom (male/female) and Cervical cap

Question 8.
Progestasert is a hormone-releasing IUD. Identify another hormone-releasing IUD.
Answer:
LNG 20

Question 9.
Genital herpes is a non-curable STP even if detected earlier. Name two other non-curable STDs.
Answer:
Hepatitis-B, AIDS.

Question 10.
Identify the method in which sperm is directly injected into the ovum for the formation of embryo,
(a) Al
(b) IUT
(c) ICSI
(d) ET
Answer:
(c) ICSI

Question 11.
Certain techniques are used to assist infertile couples to produce children.

1. Name the technique used to assist infertile couples.
2. Give two examples for this type of technique which is used to address male infertility.

Answer:

1. IVF (Test tube baby), Al, ZIFT, GIFT, IUI, ICSI

2. Technique which is used to address male infertility:

• Al
• IUI

Question 12.
A female cannot produce ovum, but can provide suitable environment for fertilization and further development. Suggest the ART which is more suitable for the lady.
Answer:
GIFT

Question 13.
After IVF, the embryo is transferred either to fallopian tube or to uterus. Name the ET method used when the embryo has not reached eight celled stage.
Answer:
ZIFT

Plus Two Zoology Reproductive Health Two Mark Questions and Answers

Question 1.
Syphilis, Gonorrhea are the common STDs. Suggest any two method to prevent the infection of disease.
Answer:

• Avoid sex with unknown partner/ multiple partners
• Always use condoms during coitus.

Question 2.
Do you think that the contraceptive measures should be encouraged. Explain your opinion with reason.
Answer:
Yes, because

1. contraceptives motivate smaller families
2. check population explosion
3. prevent unwanted pregnancies
4. help to space children.

Question 3.
A list of contraceptive methods are given. Categorise them into natural, barrier, IUDS, Oral contraceptives, Surgical. Condoms, Coitus interruptus, Diaphragms, Vasectomy, CopperT, Pills, Lactational Amenorrhea, Loop, Tubectomy, Cervical caps, Cu 7, Periodic Abstinence.
Answer:

Question 4.
A couple having no kids for several years consulted a doctor. After continuous diagnosis, the Doctor advised hormonal treatment for the lady.

1. Name the hormone, which is deficient in the lady.
2. State how this hormone help the lady to become pregnant.

Answer:

1. LH/FSH/Progesterone
2. FSH helps for the growth and maturation of ovarian follicles. LH helps for ovulation. Progesterone maintains pregnancy.

Question 5.
Given below are four methods and their modes of action in achieving contraception. Match the following.

1. Pill – Prevents sperm reaching cervix
2. Condom – Prevents implantation
3. Vasectomy – Prevents ovulation
4. CopperT – Semen contain no sperm

Answer:

1. Pill – Prevents ovulation
2. Condom – Prevents sperm reaching cervix
3. Vasectomy – Semen contain no sperm
4. CopperT – Prevents implantation

Question 6.
Observe the relationship between the first two words and fill up the blanks.

1. HIV – ELISA test; Typhoid – ________
2. Male – Vasectomy; Female -_______

Answer:

1. Widal test
2. Tubectomy

Question 7.

1. How do the oral pills help in birth control?
2. Name common pills use.

Answer:

1. They are used in the form of tablets which contain progesterone and estrogen. Pills have to be taken daily for a period of 21 days starting within the first five days of menstrual cycle. They inhibit ovulation and implantation.

2. Common pills

• Mala D
• Saheli

Question 8.
Is the use of contraceptives justified? Give reasons.
Answer:
Yes, the use is justified.
Population in India is increasing at a very fast rate. To overcome this problem and to have small family, the use of contraceptive could be the best option.

Question 9.
Tubectomy is a method of female sterilization. How is it surgical procedure helps in female sterility?
Answer:
In tubectomy, a small part of the fallopian tube is removed ortied up through a small incision, so that no ovum can be transported to uterus, thus preventing pregnancy.

Question 10.

1. Do you think that reproductive health in our country has improved in the past 50 years?
2. If yes, mention some such areas of improvement.

Answer:

1. Yes, the programmes like family planning and reproductive and child health care have been successfully launched.

2. Now more people are aware about the advantages of small family and are accepting two children norm, some such areas of improvement are massive child immunization, increasing the use of contraceptives, family planning etc.

Question 11.
A mother of one-year-old daughter wanted to space her second child. Her doctor suggested CuT. Explain its contraceptive actions.
Answer:
CuT release Cu²⁺ ions which suppress sperm motility. Increases Phagocytosis of sperms and reduces their fertilizing capacity.

Question 12.

1. Name the hormonal composition of the oral contraceptive used by human females.
2. Explain how does it act as a contraceptive?

Answer:

1. Pills contain progesteron – estrogen combination.
2. They inhibit ovulation and implantation.

Question 13.
A couple who visited an infertility clinic realised that the lady can not produce an ovum but conceive provide suitable environment and deliver a child. Doctor suggested ‘ART’ for them. Suggest the most suitable ART technique for this couple. Write the reason for suggesting the method.
Answer:
GIFT-(Gamete Intra fallopian transfer). Here transfer of an ovum collected from a donor into the fallopian tube of the female, who can not produce ovum.

Or IVF, where Ova from donor and husband’s sperms are induced to form zygote in the laboratory, then transfer into the wife’s uterus/oviduct.

Question 14.
Contraceptive methods are used to block unwanted pregnancies. What are the qualities of an ideal contraceptive?
Answer:
User-friendly, low cost, easily available, reversible, less side effects. Do not interfere sexual act or sexual drive.

Question 15.
Amniocentesis is a prenatal diagnostic test. Now a days it is widely misused as a test for determining the sex of the foetus. The misuse of the test for foetal sex determination is legally banned today. As a plus two biology student give your comments on the issue.
Answer:
Primary objective is prenatal diagnosis of Genetic disorders. However, it used widely for foetal Sex determination leading to female foeticide

Question 16.
The permanent methods of contraception are more effective’ in contraception than any temporary methods.

1. Identify two permanent methods of contraception.
2. Mention the demerits of permanent method.

Answer:

1. Vasectomy and Jubectomy

2. demerits of permanent method:

• Irreversible method
• require hospitalisation

Question 17.
Government of India legalized MTP in 1971 with some strict conditions to avoid its misuse.

1. Define MTP.
2. Suggest the possibilities to legally perform MTP.

Answer:

1. Medical termination of pregnancy

2. Suggest the possibilities to legally perform MTP:

• In conditions of poor maternal health.
• To avoid unintended pregnancies
• unprotected sex or failure of contraceptives lead to unintended pregnancies.

Question 18.
Diseases or infections which are transmitted through sexual intercourse are collectively called STDs.

1. Suggest two methods to prevent STD.
2. Name two examples for STD.

Answer:

1. Suggest two methods to prevent STD:

• Avoid sex with unknown persons
• use condom
• if doubt go to a qualified doctor for early detection.

2. Gonorrhoea, Syphilis, Genital herpes, Chlamydiasis, Genital wart, Trichomoniasis, Hepatitis-B and AIDS.

Question 19.
Population explosion is major problem facing India.

1. Justify the statement with reasons
2. Suggest any two relevant measures to control overpopulation.

Answer:

1. Population explosion is the major single cause behind Poverty and increase competition.
2. Family planning method. Natural method or IUD or use of contraceptives or raising of marriageable age.

Question 20.
AIDS can be transmitted through sexual contact.

1. Expand AIDS.
2. Suggest any two other methods by which humans could be affected with AIDs.

Answer:

1. Acquired Immuno Deficiency Syndrome
2. Blood transfution, Infected mother to foetus or intravenous drug injection.

Question 21.
On clinical examination, it is found that a pregnant lady carrying a defective foetus.

1. Suggest a technique used to get rid of the defective foetus.
2. Name anyone demerit found associated with the suggested technique.

Answer:
1. MTP (Medical termination of pregnancy.
2. Medical Termination of Pregnancy (MTP) is a procedure that is carried out under anaesthesias increases the risk for the procedure. There are high chances of patient having recurrent abortions or may be negatively used to kill female foeticide.

Question 22.
In India, reproductive health care has been improving because of new and effective policies taken up by the health department. Name two programmes launched by Govt, of India to attain reproductive health among the people.
Answer:
Family planning Reproductive & child health care programmes (RCH)

Question 23.
CuT is a contraceptive device.

1. Suggest the contraceptive action of CuT.
2. Name two hormone-releasing lUDs.

Answer:

1. Prevent sperm motility. Or Phagocytosis of sperm
2. Progestasert, LNG 20

Plus Two Zoology Reproductive Health Three Mark Questions and Answers

Question 1.
A newly married couple wants temporary birth control measures for six months.

1. Which contraceptive is ideal for them?
2. What are the features one would find in an ideal contraceptive?
3. What is the advantages and disadvantages of natural methods?

Answer:

1. Condoms/oral contraceptive pills
2. It must be user-friendly, easily available, effective and reversible with nor or lease side effect and in no way interfere with sexual drive.
3. The advantage of natural methods is that there is no side effects. But the chances of failure is high.

Question 2.
Notice shown in front of recognised scanning centres says ‘Sex determination is illegal’.

1. Name the method of sex determination in the early stages other than scanning.
2. What is the advantage of this technique?
3. How people misuse it?

Answer:

1. Amniocentesis.
2. It is a foetal sex determination test based on chromosomal pattern in the amniotic fluid. It helps to know the chromosomal abnormalities in advance.
3. Sex determination sometimes leads to the killing of female foetus.

Question 3.
Match the items in column A with those of column B.

Answer:

Question 4.
A 9-year-old girl accidentally consumes contraceptive pills regularly for 2 months.
(Hint: Contraceptive pills contains estrogen)

1. What type of change you expect in the body of the girl?
2. How it affects her reproductive development?
3. Do you think the stoppage of the pills will reverse the system? If so, give details.

Answer:

1. The girl begins to exhibit female secondary sexual characters.
2. Overall physiological processes involved in reproduction increases.
3. If she attains puberty during this stage, the system will continue, otherwise, it may be reverse the system.

Question 5.
Match the following.

Answer:

Question 6.
Infertility cases are increasing now a days. These couples could be assisted to have children through certain special techniques called ART.

1. What is ART?
2. Name two methods in ART.
3. Why IVF is called test-tube baby?

Answer:
1. Assisted reproductive technique.

2. two methods in ART:

• GIFT (Gamete Intra Fallopian Transfer)
• ZIFT (Zygote Intra Fallopian Transfer)
• IVF (Invitro fertilization)
• ICSI (Intra Cytoplasmic Sperm Injection)
• IVI (Intra Uterine Insemination)

3. In IVF, ova from the donor and sperm from the male donor are collected and induced to form zygote under stimulated conditions in the laboratory.

Question 7.
The incidences of STDs are high among persons in the age group of 15-24 years:

1. What is STD?
2. Name some common STDs (Any four).
3. What are the principles you have follow to prevent it?

Answer:

1. Sexually transmitted diseases.

2. Gonorrhoea, syphilis, genital herpes, hepatitis B, AIDS, genital warts, trichomoniasis (any four)

3. principles you have follow to prevent it:

• Avoid sex with unknown partners/multiple partners.
• Always use condoms during coitus.
• In case of doubt, go for early detection and get complete treatment if diagnosed with disease.

Question 8.
Different type of contraceptives are available. A couple wants to space children after their first child.

1. What is the ideal contraceptives suggested for female to delay pregnancy or space children?
2. Name the surgical sterilization methods adopted to prevent any more pregnancies.
3. What is the action of Cu ion releasing contraceptives?

Answer:

1. IUDs (Intra Uterine Devices) like CopperT, Lipper Loop, Cu 7 etc.
2. Vasectomy for male and Tubectomy for female.
3. Cu ions released within the uterus suppress sperm motility and the fertilising capacity of sperms.

Question 9.
Nearly 45 to 50 million MTPs are performed in a year all over the world which accounts to 1/5th of the total number of conceived pregnancies in a year.

1. What is MTP?
2. What is the actual aim of it?
3. Which period of pregnancy is safe for MTP?

Answer:
1. Medical Termination of Pregnancy or induced abortion.

2. The aim of MTP is to get rid of unwanted pregnancies either due to casual unprotected intercourse or failure of contraceptives used during coitus. It is essential, when continuation of pregnancy could be harmful or fatal to mother or foetus or both.

3. MTPs are relatively safe during the first trimester.

Question 10.
In India, often females are blamed for the couple being childless.

1. Do you agree with the statement? Why?
2. How a male, who cannot inseminate the female could be corrected?
3. How IUI is conducted?

Answer:

1. There is equal chances for a male or a female partners to cause infertility.
2. Artificial insemination
3. The semen collected from the husband or a healthy donor is artificially introduced into the uterus of female is called Intra Uterine Insemination (IUI).

Question 11.
Match Column A with Column B and Column C.

Answer:

Plus Two Zoology Reproductive Health NCERT Questions and Answers

Question 1.
Suggest the aspect of reproductive health which need to be given special attention in the present scenario.
Answer:
Control on over population through programmes like family planning and Reproductive and child health care (RCH).

Creating awareness among the people about various aspects such as STDs, available birth control methods, postnatal care of mother and child, adolescence and related changes, sex education, etc.

Question 2.
Is sex education necessary in schools? Why?
Answer:
Yes. It will provide right information about sexto the children. Such education will also discourage children from believing in myth and misconception about sex related aspects.

Question 3.
Do you think that reproductive health in our country has improved in the past 50 years? If yes, mention some such areas of improvement.
Answer:
Yes, the programmes like family planning and reproductive and child health care have been successfully launched.

Now more people are aware about the advantages of small family and are accepting two children norm. Some such areas of improvement are massive child immunization, increasing use of contraceptives, family planning etc.

Question 4.
What are the suggested reasons for population explosion?
Answer:

1. Decline in death rate, maternal mortality rate and infant mortality rate.
2. Increase in number of people in reproductive age.
3. Control of diseases
4. Better public health care and greater medical attention.

Question 5.
Is the use of contraceptives justified? Give reasons.
Answer:
Yes, the use is justified. Population in India is increasing at a very fast rate. To overcome this problem and to have small family,

Question 6.
Anniocentesis for sex determination is banned in our country. Is this ban necessary? Comment.
Answer:
In India, Amniocentesis was banned under prenatal Diagnostic Techniques (Regulation and Prevention of Misuse) Act which was enforced in 1994. According to this Act, all the genetic counseling centres and laboratories are required to apply for registration.

It was must because the technique was being misused. Mothers started even get their normal foetus aborted if it was a female. So this Act is aimed to legally check increasing female foeticide which is causing an unfavourable sex ratio.

Question 7.
Suggest some methods to assist infertile couples to have children.
Answer:
Infertile couples may be helped to have children by the following techniques:
Technique

1. In-vitro-fertilization-embryo transfer (IVF-ET) technique:
ZIFT (Zygote intrafallopian transfer); Ovum of female and sperms of male are induced to form zygote in a culture medium and then embryo is transferred in the female for further developments.

It is of two types: Embryo is transferred in the fallopian tube of female at the stage of 8 blastomeres. IUT (Intra-uterine transfer); Embryo is transferred in the uterus at 32-celled stage

2. GIFT (Gamete intrafallopian transfer):
Transfer of an ovum of a female into fallopian tube of another female for fertilization by sperms of former’s husband.

3. ICSI (Intra-cytoplasmic sperm injection):
Sperm of male is directly injected into ovum of female.

4. Al (Artificial insemination):
Sperms of husband (AIH) or a donor male are artificially introduced into the vagina or uterus of the female.

Question 8.
Removal of gonads cannot be considered as a contraceptive option. Why?
Answer:
It is because an ideal contraceptive should be

1. user-friendly
2. with no or least side effect
3. should not interfere with sexual drive, desire and the sexual act of the user.

When gonads are removed, the basic function of reproductive system such as secretion of hormones and gamete production is not possible.

Plus Two Zoology Reproductive Health Multiple Choice Questions and Answers

Question 1.
Rapid decline in population due to high mortality rate is called:
(a) Population density
(b) Population crash
(c) Population explosion
(d) All of these
Answer:
(b) Population crash

Question 2.
Pre-natal defects in the foetus can be detected by:
(a) Laparoscopy
(b) Genetic engineering
(c) MRI
(d) Aminocentesis
Answer:
(d) Aminocentesis

Question 3.
Saheli, a female antifertility pill, is used:
(a) Daily
(b) Weekly
(c) Quarterly
(d) Monthly
Answer:
(b) Weekly

Question 4.
Fertilization of ovum can be prevented by:
(a) Tubal ligation
(b) Vasectomy
(c) Use of 1UDs
(d) All of these
Answer:
(d) All of these

Question 5.
Infant mortality in India is:
(a) 14/1000
(b) 45/1000
(c) 62/1000
(d) 72/1000
Answer:
(d) 72/1000

Question 6.
On which day, world population touched 5th billion?
(a) May 11, 1985
(b) July 11, 1986
(c) May 11, 1987
(d) July 11, 1987
Answer:
(d) July 11, 1987

Question 7.
According to 2001 census, Indian population was:
(a) 684 millions
(b) 844 millions
(c) 1027 millions
(d) 1128 millions
Answer:
(c) 1027 millions

Question 8.
Which period of menstrual cycle is called risky period of conception?
(a) 3^rd to 7^th day
(b) 7^th to 13^th day
(c) 10^th to 17^th day
(d) 15^th to 25^th day
Answer:
(c) 10^th to 17^th day

Question 9.
Test tube baby is a technique where:
(a) Zygote is taicen from ovary, cultured and Implanted in the uterus
(b) Ovum is taken from ovary, then fertilized outside and then implanted in the uterus
(c) Sperm and ovum are fertilized and grow test tube
(d) None of the above
Answer:
(b) Ovum is taken from ovary, then fertilized outside and then implanted in the uterus

Question 10.
Copper-T loop prevents:
(a) Ovulation
(b) Zygote formation
(c) Fertilization
(d) cleavage
Answer:
(c) Fertilization

Question 11.
Intra-uterine devices (lUDs) are used to prevent
(a) Sperm to reach ovum
(b) sperm to reach female
(c) Sperm from leaving testes
(d) all of these
Answer:
(a) Sperm to reach ovum

Question 12.
11^th July is celebrated as:
(a) World AIDS Day
(b) World Environment Day
(c) World population day
(d) World Science and Technology Day
Answer:
(c) world population day

Question 13.
Test tube baby means a baby born when:
(a) It is developed in a test tube
(b) It develops from a non-fertilized egg
(c) The ovum is fertilized externally and there after implanted in uterus
(d) It is developed by tissue culture method
Answer:
(c) The ovum is fertilized externally and there after implanted in uterus

Question 14.
The first case of IVF-ET technique success, was reported by:
(a) Bayliss and Starling Taylor
(b) Robert Steptoe and Gilbert Brown
(c) Louis Joy Brown and Banting Best
(d) Patrick Steptoe and Robert Edwards
Answer:
(d) Patrick Steptoe and Robert Edwards

Plus Two Zoology Reproductive Health SCERT Sample Questions and Answers

Question 1.
Name the surgical methods of birth control, write the merit and demerit of the above methods. (2)
Answer:
In vasectomy, a small part of the vas deferens is removed or tied up through a small incision on the scrotum In tubectomy, a small part of the fallopian tube is removed or tied up through a small incision in the abdomen or through vagina.
Merit – highly effective
Demerit – Reversibility is poor.

Question 2.
In AIDS, HIV attacks on (Helper-T cells, B – Lymphocytes, Monocytes, RBC)    (1)
Answer:
Helper T -Cells

Students can Download Chapter 1 Human Reproduction Questions and Answers, Plus Two Zoology Chapter Wise Questions and Answers helps you to revise the complete Kerala State Syllabus and score more marks in your examinations.

Kerala Plus Two Zoology Chapter Wise Questions and Answers Chapter 1 Human Reproduction

Plus Two Zoology Human Reproduction One Mark Questions and Answers

Question 1.
Vasa efferentia are the ductules leading from
(a) testicular lobules to rete testis
(b) rete testis to vas deferens
(c) vas deferens to epididymis
(d) epididymis to urethra
Answer:
(b) rete testis to vas deferens.

Question 2.
In human, the unpaired male reproductive structure is
(a) seminal vesicle
(b) prostate
(c) bulbourethral gland
(d) testes
Answer:
(b) prostate.

Question 3.
The semen fluid consists of sperm cells and secretion from
(a) seminal vesicle, prostate gland, Cowper’s gland
(b) seminal vesicle, testis, uterus
(c) seminal vesicle, prostate gland, testis
(d) seminal vesicle, Cowper’s gland, and testis
Answer:
(a) seminal vesicle, prostate gland, Cowper’s gland.

Question 4.
Onset of menstruation of human female is called
(a) menopause
(b) puberty
(c) gestation
(d) menarche
Answer:
(d) menarche

Question 5.
Ovulation in the human female normally takes place during the menstrual cycle
(a) at the mid secretory phase
(b) just before the end of the secretory phase
(c) at the beginning of the proliferative phase
(d) at the end of the proliferative phase
Answer:
(d) at the end of the proliferative phase

Question 6.
The implanted stage during embryonic development?
(a) Gastrula
(b) Morula
(c) Zygote
(d) Blastocyst
Answer:
(d) Blastocyst

Question 7.
Find out the odd one and justify your answer. Estrogens, Androgens, Relaxin, Progestrogens.
Answer:
Androgens.
All others are female hormones.

Question 8.
Choose the correct answer from the bracket.
The implanted stage during embryonic development?
(a) Gastrula
(b) Morula
(c) Zygote
(d) Blastocyst
Answer:
(d) Blastocyst

Question 9.
Infants acquire passive immunity from mothers. Name the means of acquiring this type of immunity.
Answer:
Colostrum

Question 10.
A spermatogonial cell has 30 chromosomes. How many chromosomes will be found in

1. the primary spermatocyte
2. the spermatid?

Answer:

1. 30
2. 15

Question 11.
Select from the following the one that is not the part of testis.
(a) Testicular lobules
(b) Sertoli cells
(c) Primary follicles
(d) Leydig cells
Answer:
(c) Primary follicles

Question 12.
Complete the series.

1. Secreatory phase-progesterone,…………… Oestrogen
2. Implantation-uterus, Fertilization-……………

Answer:

1. Follicular phase
2. Fallopian tube

Question 13.
Find out the correct sequence.
(a) Fertilization —Zygote —Blastula — Morula — Clevage
(b) Clevage—Zygot—Fertilization—Morula— Blastula
(c) Fertilization—Clevage—Morula—Blastula— Zygot
(d) Fertilization—Zygot—Clevage—Morula— Blastula.
Answer:
(d) Fertilization—Zygot—Clevage—Morula— Blastula.

Question 14.
Identify the hormone produced by testis,

1. Thyroxine
2. Estrogen
3. Progesterone
4. Testosterone

Answer:
Testosterone

Question 15.
Normally, scrotum has a temperature below body temperature. Give the significance.
Answer:
Lower temperatures promote spermatogenesis.

Question 16.
Cowper’s gland is an accessory reproductive gland. Name two other glands associated with male reproductive system.
Answer:
vesicle and Prostate gland.

Question 17.
Find out the first cell which is formed as haploid during spermatogenesis.
(a) Spermatogonia
(b) Primary spermatocyte
(c) Secondary spermatocyte
(d) Sperm
Answer:
(c) Secondary spermatocyte

Question 18.
The urine sample of a lady contains HCG. As a biology student, what conclusion can you draw from the result?
Answer:
The woman is pregnant

Question 19.
In testes, the newly formed sperms are temporarily stored in……………..
(a) Rete testis
(b) Seminiferous tubule
(c) Epididymis
(d) Vas deferens
Answer:
(c) Epididymis

Question 20.
Human Chorionic Gonadotropin (HCG) is a hormone produced during pregnancy. Identify two other hormones produced during pregnancy.
Answer:
HPL and Relaxin

Question 21.
“The trophoblast layer gets attached to the endometrium and the inner cell mass get differentiated into embryo.” Identify the scientific term for the attachment of blastocyst to the endometrial lining of the uterus.
Answer:
Implantation

Question 22.
Foetal ejection reflex is initiated by a pituitary hormone, which is called child birth hormone. Mention the name of child birth hormone.
Answer:
Oxytocin

Question 23.
Testosterone is secreted by………….
(a) Sertoli cells
(b) Leydig cells
(c) Follicle cells
(d) Seminiferous tissue
Answer:
(b) Leydig’s cell

Question 24.
Ovulation normally takes place at the middle of menstrual cycle. Name the part of the oviduct that collects ovum from the ovary.
Answer:
Fimbriae

Question 25.
Internal lining of fallopian tube is made up of ciliated epithelium. Justify the role of ciliated epithelium in oviduct.
Answer:
Helps the movement of non motile ovum.

Question 26.
Acrosome is a cap-like structure found in the head of sperm. Write its function.
Answer:
Breaking of egg membranes with enzymes during fertilization.

Question 27.
Read the statements and choose the correct option.
A: The endometrium undergoes cyclical changes during menstrual cycle.
B: Perimetrium exhibits strong contractions during delivery of the baby
C: Myometrium is outer glandular layer which produce hormones.
(a) Statement ‘A’ alone is correct.
(b) Statements ‘A’ and ‘B’ are correct
(c) Statements ‘A’ and ‘C’ are correct
(d) Statement ‘C’ alone correct
Answer:
‘A’

Question 28.
Select the correct path of sperm movement in the male reproductive system
(a) Seminiferous tubule, Vasa efferentia, Vas deferens, Epididymis, Urethra, Rete testis
(b) Rete testis, Epididymis, Vasa efferentia, vas deferens, Seminiferous tubule, Urethra
(c) Seminiferous tubule, Rete testis, Vasa efferentia, Epididymis, Vas deferens, Urethra
(d) Seminiferous tubule, Vas deferens, Epididymis, Rete testis, Urethra, Vasa efferentia
Answer:
(C) Seminiferous tubule, Rete testis, Vasa efferentia, Epididymis, Vas deferens, Urethra

Plus Two Zoology Human Reproduction Two Mark Questions and Answers

Question 1.
The temperature of the testis is 2.5 degree C lower than body temp. Give reason. Name the hormone produced from the testis?
Answer:
Lower temperature is necessary for sperm formation in the testis. Testis produce the hormone Androgen.

Question 2.
How many eggs are released by a human ovary in a month? How many eggs do you think would have been released if the mother gave birth to identical twins? would your answer change if the twins? Would your answer change if the twins born were fraternal?
Answer:
Only one egg is released by human ovaries in a month. Single egg was released in case of identical twins. In case of fraternal twins, two eggs are released and get fertilized.

Question 3.
A pregnant lady has intercourse with her husband and sperms are ejaculated on the cervix which may not enter into the uterus.

1. Why the sperms cannot enter into the uterus?
2. What are the other means by which the embryo is protected?

Answer:

1. In a pregnant lady, there is no scope of entry of new sperms to uterus for fertilization. It is blocked by plug at the cervix.
2. Foetus is protected by the foetal membranes such as amnion, chorion, allantois and yolk sac.

Question 4.
The diagram of Human blastocyst is given below.

1. Identify A and B.
2. Mention the fate of A and B.

Answer:

1. A-Inner cell mass B – Trophoblast
2. Inner cell mass gives rise to embryo, Trophoblast – Foetal membranes, and placenta.

Question 5.
Give reason. ‘Corpus luteum functions as endocrine organ’.
Answer:
Corpus luteum secretes progesteron, a hormone, which helps for pregnancy.

Question 6.
Observe the flow chart showing the hormonal control of menstrual cycle.

1. Observe and name the hormones A, B, C and D.
2. Copy the flow chart and represent the feedback mechanism in that.

Answer:
1. A-FSH, B-L.H,
C – Estrogen D – Progesterone
2.

Question 7.
The relaxin secreted by placenta relaxes the public ligaments during parturition.

1. What is placenta?
2. Mention any two other hormones secreted by placenta.

Answer:

1. Placenta is the physiological connection between mother and developing young one.

2. Any two other hormones secreted by placenta:

• HCG (Human chorionic gonadotropin)
• HPL (Human Placental lactogen)

Question 8.
Redraw the following diagram and label the parts 1 to 5.

Answer:

1. – Acrosome
2. – Nucleus
3. – Neck
4. – Mitochondria
5. – Tail

Question 9.
Study the picture showing events of menstrual cycle and answer the following questions.

1. Name the major hormones responsible for the events shown in stage 1 and 2.
2. Identify the structure shown in stage 3 and comment on its fate.

Answer:

1. FSH and LH
2. Corpus Luteum. It secretes progesteron for the maintenance of pregnancy. If fertilization fails to occur, it transforms into corpus albicang and degenerates.

Question 10.
Eggs are developed and matured in the ovary. Mature ovum released from ovary by ovulation.

1. How many eggs are released by a human ovary in a month?
2. How many eggs do you think would have been released if the mother gave birth to identical twins?

Answer:

1. Normally one per month.
2. Single ovum is released, which is fertilized by a single sperm. After fertilization, the zygote cleaves to form two identical twins.

Question 11.

1. Identify the figure and label portions A and B.
2. How many chromosomes are present in human secondary spermatocyte?

Answer:

1. A – Spermatogonia ; B – Interstitial cells
2. 23 chromosomes

Question 12.
Name the structure with the following components.

1. Embryo at 16 cell stage
2. Mature ovum with follicle cells
3. Myometrium and endometrium
4. Trophoblasts, inner cell mass, blastcoel

Answer:

1. Morula
2. Graffian follicle
3. Uterus
4. Blastocyst

Question 13.
The diagram A & B show the important events in human reproduction.

1. Give the name of these two processes, A & B seen in human reproduction.
2. If there are differences in the processA& B, give details of it.

Answer:

1. A – Spermatogenesis
   B – Oogenesis
2. In spermatogenesis, meiotic division is equal leading to the formation of many functional sperms. Oogenesis division is unequal leading to the formation of a single ovum and other polar bodies degenerate.

Question 14.
Given the figure of section of ovary, label A and B. What is the significance of B if the egg fertilized.

Answer:
A – Primary follicle B – Corpus leuteum
If egg is fertilized, corpus luteum secretes more progesterone, preparing endometrium for pregnancy.

Question 15.
Identify true/false statements. Correct if it is false.

1. Sperms get nutrition from sertoli cells.
2. Leydig cells are found in ovary.
3. Presence or absence of hymen is not a reliable indicator of virginity or sexual experience.
4. The first menstruation starts at puberty is called menopause.

Answer:

1. True
2. False. Leydig cells are found in testis.
3. True
4. False. The first menstruation is called menarch.

Question 16.
Observe the diagram.

Identify the labelled part A, B, C, and D.
Answer:
(A) Chrionic villi/placenta
(B) Yolk sac
(C) Umbilical cord
(D) Amniotic fluid

Question 17.
Name the foetal membrane that provides a fluid medium to the developing embryo. Mention its two functions.
Answer:
Amnion

1. It prevents desiccation of the embryo.
2. It provides a kind of private aquarium to the embryo and protects it from shocks.

Question 18.
Milk is secreted in the alveoli of mammary glands. Make a flow chart of the movement of milk from the alveoli to the buccal cavity of new born during breast feeding.
Answer:

Question 19.

1. What is parturition?
2. Which hormones are involved in induction of parturition?

Answer:

1. The process of delivery of the foetus is called parturition.
2. Oxytocin (Birth Hormone)

Question 20.
Germinal epithelium lining seminiferous tubules of testis contains Sertoli cells and germ cells. Give the functional difference between Sertoli cells and germ cells.
Answer:
1. Sertoli cells:
Nourishment of developing sperms.

2. Germ cells:
Produce spermatozoa by gametogenesis.

Question 21.
‘Hymen is not a reliable indicator for virginity’. Do you agree with the statement? Give reasons.
Answer:
Yes, Hymen is a soft, delicate membrane and can be ruptured easily by sudden fall, strenuous exercises, stretching (sports), cycling, etc.

Question 22.
During coitus, semen is deposited in the vagina. Give the path of sperm movement in female reproductive tract.
Answer:
Vagina → uterus → fallopian tube.
Fertilisation takes place in ampullary isthmic junction of fallopian tube.

Question 23.
Gametogenesis is classified as spermatogenesis and oogenesis. Differentiate between spermatogenesis and oogenesis.
Answer:
Production of sperm in Testes-Spermatogenesis Production of ovum in ovary – Oogenesis

Question 24.
Fertilization is the fusion of male and female gamete, which takes place in the fallopian tube.

1. Discuss and point out the changes that occurs in the ovary after fertilization.
2. Describe the changes that occurs in the uterus, if the ovum is not fertilized.

Answer:

1. Ruptured follicle transforms into corpus luteum and Progesteron hormone is released.
2. Endometrialial lining of the uterus degenerates and new uterine cycle begins.

Question 25.
Milk is produced in mammary glands towards the end of pregnancy.

1. Name the first milk produced after parturition.
2. Evaluate the advantages of getting first milk to a new born boaby.

Answer:

1. Colostrum
2. It is through the colostrum that the newborn gets maternal antibodies essential to develop immunity during early stages.

Question 26.
Write the roles of pituitary hormones in uterine and ovarian cycles in females.
Answer:
1. FSH:
promote oogenesis/influence estrogen synthesis.

2. LH:
Ovulation/Maintenance of Corpus luteum

Question 27.
Illustrate the sequential order of stages of human development from the following.
(morula, gametogenesis, cleavage, fertilization, blasulation, implantation, organogenesis, gastrulation)
Answer:
Gametogenesis → Fertilization → Cleavage → Morula → Blastulation → Implantations → Gastrulation → Organogenesis.

Question 28.
Parturition starts with foetal ejection reflex. Define foetal ejection reflex.
Answer:
Parturition signals originate from fully developed foetus which initiates uterine contractions leading to child birth.

Question 29.
A hormone injection is needed to overcome delay in delivery, Name-the hormonal injection given to enhance parturition.
Answer:
Oxytocin. It Induce stronger uterine muscle contractions leading to quicker expulsion of the baby.

Question 30.
Identify and label the parts where the following events occur.

1. Fertilization
2. Implantation

Answer:

1. Ampullary isthmus region of fallopian tube
2. Endometrium

Question 31.
Placenta is a physiological connection between mother and foetus. Placenta is also an endocrine gland. Complete the given illustration with the hormones produced by the placenta.

Answer:
Progesterone, HCG, HPL, Relaxin.

Question 32.
Arrange the following terms in two columns with suitable headings. (Seminiferous tubule, Uterus, vas deferens, Cervix, vagina, Epididymis)
Answer:
Male reproductive system

• Seminiferous tubule
• Vas deferens
• Epididymis

Female reproductive system

• Vagina
• Cervix
• Uterus

Plus Two Zoology Human Reproduction Three Mark Questions and Answers

Question 1.
Observe and study the graph.

1. Find the relationship between FSH and Progesterone.
2. What is the function of FSH?
3. During pregnancy, how ovulation and menstruation prevented.

Answer:

1. When FSH decreases progesterone increases.
2. Formation and maturation of ovarian follicles.
3. Because of high levels of progesterone. Progesterone inhibits the production of FSH, which helps for ovulation.

Question 2.
Based on the given diagram, prepare a flow chart explaining the process of spermatogenesis.

Answer:

Question 3.
Diagrammatic presentation of various events during a menstrual cycle is given.

1. Identify the uterine events A, B
2. Name the ovarian hormones D&E.
3. What happens to the level of E, if the ovum gets fertilized?

Answer:

1. A – Menstrual phase
   B – Proliferative/ follicular phase
2. D – Estrogen
   E-Progesterone
3. The level of progesterone will increase after 20^th day and it maintains even after 28^th day.

Question 4.
A pregnant lady was admitted to a hospital for delivery, but delivery is delayed than the expected time. Doctor prescribed to take a hormone injection.

1. Name the hormone?
2. Which gland in the body normally secrete this hormone?
3. How this hormone helps in delivery?

Answer:

1. Oxytocin
2. Pituitary gland
3. Oxytocin helps for the contraction of uterine muscles to facilitate delivery.

Question 5.

1. When and how does placenta develop in human female?
2. How is the placenta connefcted to the embryo?
3. Placenta acts as an endocrine gland. Explain.

Answer:
1. Placenta develops after implantation. Finger-like projections (chorionic villi) appear on the tropho-blast which are surrounded by the uterine tissue and maternal blood. The chorionic villi and uterine tissue become interdigitated with each other and thus placenta is formed.

2. Through umbilical cord

3. Placenta secretes the following hormones:

• Human chorionic gonadotropin (hCG).
• Human placental lactogen (HPL)
• Progesterons and estrogens.

Question 6.
In female ovum is released normally on the 14^th day of menstrual cycle.

1. Name the process of release of ovum from the ovary.
2. Where does the fertilization occur?
3. What will happen to the grafian follicle if the ovum is fertilized?

Answer:

1. Ovulation
2. Fallopian tube
3. It transforms into corpus luteum.

Question 7.
The following diagrams show the sequence of events in the development of mature of ovarian follicle and corpus luteum.

1. Which are the main hormones produced by the ovary at the stages C & E?
2. Which among the stages A to E would you expect is maintained by the ovary during pregnancy. Give reasons for your answer.
3. Identify C.

Answer:

1. The hormones produced are C – Estrogen E – Progesterone
2. E is maintained (Corpus luteum)
   Corpus luteum is necessary to produce progesterone which maintains pregnancy.
3. Mature graffian follicle.

Question 8.
FSH and LH are the hormones released by both female and males

1. Which gland produce these hormones?
2. Mention effects these hormones in the males and females?
3. An ideal male contraceptive might be one that would suppress release of FSH but not of LH discuss. Why?

Answer:
1. Testis and Ovary.

2. FSH in female stimulates development of follicle, LH stimulates follicular development and development of corpus luteum. FSH in male stimulates sperm production, LH stimulates interstial cells to produce testosterone.

3. It suppress sperm production but not testosterone production, so male would be infertile but would still develop male secondary sexual characteristics.

Question 9.
Give reasons to the following.

1. Newborn babies should strictly fed colostrum.
2. Sex of the baby is determined by the father and not by the mother.
3. Doctors inject oxytocin to induce delivery.

Answer:
1. Colostrum is the first milk, which contain several antibodies absolutely essential for developing resistance for new born babies.

2. Females produce gametes with X only. Males, on the other hand, produce sperms which carry 50 percent X and 50 percent Y chromosome. Thus zygote with XX becomes female and XY chromosome becomes male.

3. Oxytocin acts on uterine muscles and causes stronger contractions, which leads to the expulsion of baby through birth canal.

Question 10.
What are the major components of seminal plasma?
Answer:

1. The secretions of seminal vesicles, prostate gland, and cowper’s glands.
2. Spermatozoa
3. About 70% of the seminal plasma is secreted by seminal vesicles. It is rich in fructose, citrate, prostaglandins and certain enzymes.

Question 11.
During Oogenesis, in human female, a primary oocyte produces four haploid cells. Out of these four haploid cells, only one is used in reproduction. Then

1. What is the fate of the haploid cells used in reproduction?
2. What happens to the other three haploid cells?
3. What is the significance of this type of meiotic division during oogenesis?

Answer:

1. Haploid cells develop into ovum/ female gamete
2. Other three haploid cells transform to polar bodies and degenerate.
3. It helps for reducing chromosome number and also restricts the number of ovum.

Question 12.
The graph shows the level of ovarian hormones in a normally menstruating woman during follicular phase.

1. Name ‘a’ and ‘b’.
2. Mention the role of pituitary hormones in maintaining this condition.
3. Reconstruct the hormonal graph for luteal phase.

Answer:

1. a. Estrogen
   b. Progesteron
2. FSH :
   Influence spermatogensis and oogenesis/ influence estrogen hormone
   LH :
   Ouvlation / Maintenance of Corpus luteum

Question 13.
Placenta facilitates the supply of O₂ and nutrients to the embryo and removal of CO₂ and excretory waste products produced by the embryo. Apart from this, placenta is considered as an endocrine tissue. Justify.
Answer:
Placenta produces a number of hormones, which are inevitable for pregnancy and parturition. They are:

1. Human chorionic gonadotropins (HCG)
2. Human placental lactogen (HPL)
3. Estrogen
4. Progesterone
5. Relaxin etc.

Question 14.
Analyse the process of gametogenesis given below. Answer the following questions.

1. Identify and name the type of gametogenesis illustrated.
2. Identify cell ‘b’ & cell ‘c’ and explain their fate.
3. Compare the chromosome numbers of cell ‘a’ & cell ‘c’.

Answer:

1. Oogenesis

2. Identify cell ‘b’ & cell ‘c’ and explain their fate:

• Polar body degenerates
• Secondary oocyte develops into ovum

3. Cell ‘a’ has 46 chromosomes, and cell ‘c’ has 23 chromosomes

Question 15.
Look at the table, which summerises hormonal interaction that can occur in a female human. From the list of hormones given, select the one hormone which is most important in each of the eight pathways, 1 to 8, shown.

1. Progesterone
2. Oestrogen
3. LH
4. LH releasing factor
5. Oxytocin
6. Prolactin
7. FSH releasing factor
8. FSH

Answer:
Pathway

1. LH Releasing Factor
2. FSH releasing factor
3. LH
4. FSH
5. Prolactin
6. Estrogen
7. Estrogen Progesterone
8. Oxytocin

Question 16.
Name the hormone responsible for the descent of tests of into the scrotum. Why does the failure of the process result in sterility?
Answer:
Follicle stimulating hormone (FSH) Non descent of testes in scrotum causes sterility because spermatogenesis requires low temperature and inside the scrotum, the temperature is 2-2.5°C lower than the normal. This defect is usually cured by simple surgical process.

Question 17.
Match the column A with column B and Column C.

Answer:

Plus Two Zoology Human Reproduction NCERT Questions and Answers

Question 1.
What are the major components df seminal plasma?
Answer:

1. The secretions of seminal vesicles, prostate gland, and Cowper’s glands.
2. Spermatozoa
3. About 70% of the seminal plasma is secreted by seminal vesicles. It is rich in fructose, citrate, prostaglandins and certain enzymes.

Question 2.
What are the major functions of male accessory ducts and glands?
Answer:
Male accessory ducts store and transport the sperms from testis to the outside through urethra. Male accessory glands secrete seminal Plasma, Which is rich in fructose, citrate, prostaglandins and certain enzymes. The secretion of Cowper’s glands lubricate the penis.

Question 3.
Write functions of the following:

1. Corpus luteum
2. Endometrium
3. Acrosome
4. Sperm tail
5. Fimbriae

Answer:
1. Corpus Luteum. It secretes progesterone hor-mone which prepares the endometrium of uterus for implanation, placenation and normal development of foetus. So it maintains the pregnancy.

2. Endometrium. It is innermost, highly vascular and glandular lining of uterus. It undergoes cyclic changes during menstrual cycle and prepares itself for implanation of blastocyst and placentation.

3. Acrosome of head of sperm secretes sperm lysins like hyaluroindase (which dissolves hyaluronic acid of eff locally); corona pernetrating enzyme (which dissolves corona radiated) and acrosin (which dissolves zona pellucia).

4. Sperm tail. It shows lashing movements which provide forward push to the sperm.

5. Fimbriae are finger-like processes of fallopian tube which increase the chances of trapping of ovum released from the ovary.

Question 4.
What is oogenesis? Give a brief account of oogenesis.
Answer:
The process of formation of female gametes is called oogenesis.
Process:
During embryonic stage millions of gametes mother cells are formed (oogonia). This is covered by primary follicles. At the attainment of puberty, about 60,000 + 80,000 primary follicles are left in each overy.

Now it gets surrounded by secondary follicles. Then formation of tertiary follicle takes place. Tertiary follicle matures into Graaffian follicle – Tertiary Follicle ruptures to release secondary ooclyle by the process called ovulation.

Question 5.

1. What is menstrual cycle?
2. Which hormones regulate menstrual cycle?

Answer:
1. Menstrual Cycle. During the reproductive period of female primates, the ovaries produce ova at regular intervals of about 28/29 days and changes take place in the uterus in preparation for a possible pregnancy. This series of cyclic changes known as menstrual cycle. The most peculiarfeature of this cycle is the monthly vaginal bleeding called menses.

2. Hormonal control:

• Anterior Pituitary
• FSH
• LH
• Ovary
• Estrogen
• Progesterone

Question 6.
In our society, the women are often blamed for giving birth to daughters. Can you explain why this is not correct?
Answer:
Male produces two types of gametes (Sperms), 50% of sperms carry X chromosome, while the other 50% carry Y chromosome, while female produces only one type of gametes (ova), each carrying X chromosome. after fusion of the male and female gametes, the zygote would carry either XX or XY depending on whether the sperm carrying X or Y fertilized the ovum.

The zygote carrying XX would develop into a female baby and XY would form a male baby. Thus, the sex of the baby is determined by the father and not by the mother.

Question 7.

1. How many eggs are released by a human ovary in a month?
2. How many eggs do you think would have been released if the mother gave birth to identical twins?
3. Would your answer change if the twins? Would your answer change if the twins born were fraternal?

Answer:

1. Only one egg is released by human ovaries in a month.
2. Single egg was released in case of identical twins.
3. In case of fraternal twins, two eggs are released and get fertilized.

Plus Two Zoology Human Reproduction Multiple choice Questions and Answers

Question 1.
The part of fallopian tube closest to the ovary is
(a) isthmus
(b) infundibulum
(c) cervix
(d) ampulla
Answer:
(b) infundibulum

Question 2.
Which one of the following statements about human sperm is correct?
(a) Acrosome has a conical pointed structure used for piercing and penetrating the egg, resulting in fertilization
(b) The sperm lysins in the acrosome dissolve the egg envelope facilitating fertilization
(c) Acrosome serves as a sensory structure leading the sperm towards the ovum
(d) Acrosome serves no particular function
Answer:
(b) The sperm lysins in the acrosome dissolve the egg envelope facilitating fertilization

Question 3.
Seminal plasma in human males in rich in
(a) fructose and calcium
(b) glucose and calcium
(c) DNA and testosterone
(d) ribose and potassium
Answer:
(a) fructose and calcium

Question 4.
Sertoli’s cells are found in
(a) ovaries and secrete progesterone
(b) adrenal cortex and secrete adrenalin
(c) semiliferous tubules and provide nutrition to germ cells
(d) pancreas and secrete cholecystokinin
Answer:
(c) semiliferous tubules and provide nutrition to germ cells

Question 5.
Across section at the midpoint of the middle piece of a human sperm will show
(a) centriole, mitochondria and 9+2 arrangement of microtubules
(b) centriole and mitochondria
(c) mitochondria and 9+2 arrangement of microtubules
(d) 9+2 arrangement of microtubules only
Answer:
(c) mitochondria and 9+2 arrangement of microtubules

Question 6.
Graafian follicle contains
(a) oogonial cells
(b) corpus luteum
(c) theca externa and theca intemna
(d) corpus albicans
Answer:
(c) theca externa and theca intemna

Question 7.
Synthesis of testosterone by Leydig cells is stimulated by
(a) LTH
(b) TSH
(c) FSH
(d) ICSH
Answer:
(d) ICSH

Question 8.
Which gland in female is a counterpart of Cowper’s gland in male?
(a) Bartholin’s gland
(b) Clitoris
(c) Perineal gland
(d) None of these
Answer:
(d) None of these

Question 9.
Corpus luteum is developed from
(a) Oocyte
(b) nephrostome
(c) Graafian follicle
(d) None of these
Answer:
(c) Graafian follicle

Question 10.
Progesterone hormone is secreted by
(a) corpus albicans
(b) corpus callosum
(c) corpus luteum in ovaries
(d) corpus uteri
Answer:
(c) corpus luteum in ovaries

Question 11.
The second maturation division of the mammalian ovum occurs
(a) shortly after ovulation before the ovum makes entry into the fallopian tube
(b) until after the ovum has been penetrated by a sperm
(c) until the nucleus of the sperm has fused with that of the ovum
(d) in the Graafian follicle following the first maturation division
Answer:
(b) until after the ovum has been penetrated by a sperm

Question 12.
Which one of the following statements about morula in humans is correct
(a) It has almost equal quantity of cytoplasm as an uncleaved zygote but much more DNA
(b) It has far less cytoplasm as well as less DNA than in an uncleaved zygote
(c) It has more or less equal quantity of cytoplasm and DNA as in uncleaved zygote
(d) It has more cytoplasm and more DNA than an uncleaved zygote
Answer:
(d) It has more cytoplasm and more DNA than an uncleaved zygote

Question 13.
The signals for parturition originates from
(a) placenta only
(b) placenta as well as fully developed foetus
(c) oxytocin released from maternal pituitary
(d) fully developed foetus only
Answer:
(b) placenta as well as fully developed foetus