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Kerala SSLC Biology Model Question Paper 4 English Medium
Instructions :
- The first 15 minutes Is the Cool-off time.
- You may use the time to read the questions and plan your answers.
- Answer only on the basis of instructions and questions given.
- Consider score and time while answering.
Time: 1½ Hours
Total Score: 40 Marks
Section – A
Answer any five questions 1-6. One score each. (5 x 1 = 5)
Question 1.
Identify the disease caused by the pathoen which multiplies by taking control over the genetic mechanism of host cells.
Anthrax, SARS, AIDS, Tetanus
Answer:
SARS & AIDS
Question 2.
Select the activity which regulates the size fo the pupil according to the intensity of light.
(a) The action of ciliary muscles.
(b) The contraction of ligaments.
(c) The contraction and relaxation of iris muscles.
(d) The changes in the curvature of lens.
Answer:
(c) The contraction and relaxation of iris muscles.
Question 3.
From the following pairs, select the one that comes under the peripheral nervous system .
Answer:
(b) Cranial nerves – spinal nerves
Question 4.
Analyse the following illustration and identify the hormomes indicated as ‘A’ and ‘B’.
Answer:
A: Tropic Hormones / Releasing Hormones .
B: Oestrogen/ Progesterone
Question 5.
Analyse the illustration of DNA nucleotides and se-lect the correctly labelled one.
(a) X-phosphate, Y-ribose sugar, Z-adenine
(b) X-phosphate, Y-deoxyribose sugar, Z-guanine
(c) X-phosphate, Y-ribose sugar, Z-thymine
(d) X-phosphate, Y-deoxyribose sugar, Z-adenine
Answer:
(d) X-Phosphate, Y-Deoxyribose sugar, Z-Adenine
Question 6.
Analyse, the activities in the evolution of life and modify the flow chart by arranging them in the correct order.
Answer:
Section – B
Answer any 6 from questions 7-13. 2 Scores each (6 × 2 = 12)
Question 7.
Analyse the illustrations related to the process of blood clotting and answer the following questions.
(a) Identify A and B.
(b) How does thromboplastin form?
(c) How does the molecule labelled ‘B’ helps in the formation of a blood clot?
Answer:
a) A: Prothrombin B: Fibrin
b) Wounds cause loss of blood. Tissues degenerate to form the enzyme called thromboplastin.
c) Blood clot is formed by the entangling of plate-lets and red blood cells in the fibrin network.
Question 8.
Analyse the following symptoms and identify the dis-ease and pathogen in each.
(a) Round, red blisters on skin, spreads through contract.
(b) Obstructs lymph flow and swells lymph ducts, spreads through mosquitoes.
Answer:
(a) Disease: Ringworm Pathogen:Fungus
(b) Disease: Filariasis Pathogen: Filarial worms
Question 9.
Select suitable words from the box given below and complete the following table.
Answer:
| Part | Function |
| Myelin | Electric insulator |
| Synapse | Regulation of the speed and direction of impulse |
Question 10.
‘White blood cells have a role in an increase in body temperature.”
(a) Do you agree with this statement? Give reason.
(b) How does the rise in body temperature advanta-geous at certain occasions?
Answer:
(a) Pathogen enter the body and produce toxins as a result of metabolism, in the presence of toxin white blood cells stimulated and chemical susbtance produced, in the presence of chemi-cal substance rises the body.
(b) The rise in the body temperature reduces the rate of multiplication of pathogens and increases the effect of phagocytosis.
Question 11.
Examine the following stepsin genetic engineering to produce insulin producing bacteria and answer the following questions.
(a) Mention the function of the enzyme Ligase in this process.
(b) Write the subsequent steps in this process.
Answer:
(a) Ligase in an enzyme which is used for joining
human insulin gene and plasmid (bacterial DNA).
(b) Inserting DNA in the bacterial cell by using vectors.
- Providing a favourable medium for the mul¬tiplication of bacteria.
- Bacteria produce inactive form of insulin.
- Producing active insulin from this.
Question 12.
Analyse the names and characteristics of the or-ganisms in human evolutionary history and answer the questions.
(a) Correct mistakes if any in the names of organ-isms in A and B.
(b) Mention the major change that helped modern man to survive.
(c) Do human beings become a threat to the survival of other organisms? Substantiate your answer by giving suitable evidences.
Answer:
(a)
(b)
- Highly developed brain.
- Communication by using language.
- Ability to stand erect and walk on two legs. (Bipedal erect posture)
- Bifocal vision that helps to look at an ob-ject.
- Organized life.
- Made tools and handled it.
- Rational thinking (any two)
(c) The interference of human beings become a threat to the survival of other organisms.
Human interference has led to loss of hab-its many organisms. This results in the ex-tinction of species. Extinction of some spe-cies will lead to extinction of other species also. It is the relationship between species that helps biosphere to exist. Absence of existing, species will disrupt the delicate balance in nature, leading to total destruction.
- The hunting of animals for skin, horn etc. will cause decrease their number.
- Destruction of biodiversity leads to climate changes and in the extinction of organisms.
- Human create artificial variations through hybridization and genetic engineering.
Question 13.
“Genetic diseases can be controlled by removing disease causing genes and inserting desired genes.”
(a) Name the technique thaj makes this possible.
(b) Give the role of Human Genome Project in the growth of such techniques.
Answer:
a) Genetic engineering (Gene therapy/ gene mapping)
b) Before the invention of human genome project we couldn’t control genetic diseases. We can cure genetic diseases by removing disease causing genes from the genome and inserting normal functional genes. It helps us to overcome the problems associated with genetic disorder. Hence gene therapy is hope for hereditary dis-eases patients. The technology gene mapping helped to identify the exact gene and its location which is, responsible for particular disease.
Section – C
Answer any five from questions 14-20. 3 score each (5 × 3 = 15)
Question 14.
Analyse the illustration of internal ear and answer the questions.
(a) Write name and functions only of the body bal-ancing parts from among A, B, C and D.
(b) Write the functions performedby the other parts.
Answer:
a) A – semi circular canals – cluster of receptors in the form of hairs cells seen inside the semi circular canal help in the balancing of body.
B – Vestibular nerves: impulses are transmitted by the vestibular nerves to the cerebellum.
b) C: auditory nerve: impulses reach the cerebrum through the auditory nerve and we recognize the sound.
D : Cochlea – Cluster of receptors in the form of hairs cells seen inside the cochlea help in the hearing.
Question 15.
Analyse the given illustration related to hybridization process and answer the questions.
a) Identify A, B and C.
b) Illustrate the hybridisation experiment of a tall, round, seeded plant (TTRR) with a dwarf, wrinkled seeded plant (ttrr) to produce the first genera¬tion.
Answer:
Question 16.
Studies in the cell structure and physiology of bacteria and human being recognize the significance of a common ancestor in evolution. Write any three facts to prove this.
Answer:
- Enzymes control chemical reactions in man and bacteria.
- Energy is stored in ATP molecules.
- Genes determine hereditary traits.
- Carbohydrates, proteins and fats are basic sub-stances. (any three)
All these give clear evidence that there was a com-mon ancestor for.all living things.
Question 17.
Write any three suitable concepts for a poster exhibition in connection with the awareness programme on the topic ‘prevention of communicable diseases.’
Answer:
- Observe “dry day”.
- Do not dump waste in our surroundings.
- Do not allow stagnant water bodies in oru sur-rounding.
- Avoid the situation of multiplication of pathogen.
- Keep our surroundings clean, (any three)
Question 18.
Complete the following table by adding appropriate hormones, diseases and symptoms.
Answer:
| Hormone | Disease | Symptom |
| Thyroxine | (a) Goitre | Thyroid gland enlarges |
| Vasopressin | (b) Diabetes insipides | (c) Excess loss of water through urine |
| (d) Insulin | (e) Diabetes mellitus | Presence of glucose in urine |
| (f) Thyroxine | Myxoedema | Low metabolic rate |
Question 19.
Observe the following illustration and answer the questions.
(a) Identify the process indicated.
(b) mRNA is considered as the messenger of DNA. Why?
(c) Write the role of tRNA and ribosome in this pro- ‘ cess.
Answer:
a) Gene action / protein synthesis
b) mRNA is the molecule carries information from DNA ribosomes and controls protein synthesis.
c) tRNA (Transfer RNA): It helps to carry amino acids to the ribosome.
Question 20.
Observe the pictures of cells in specific defense and answer the following questions.
a) Identify cells A and B.
b) Write any other activity of A and B to destruct pathogens.
c) Give the reasons why their activities are known as specific defense.
Answer:
(a) A = T lymphocyte B = B-lymphocyte
(b) T- lympocyte stimulate other defense cells of the body.
T – lymphocytes are capable of destroying cells affected by virus (Any one)
B – lymphocyte – produce antibody against anti-gen.
Destroy the bacteria by disintegrating their cell membrane.
Destroy the pathogens by stimulating other white blood cells.
(c) Lymphocytes become activated in the presence of certain particular types of antigens.
Section – D
Answer any two form questions 21-24. 4 score (2 × 4 = 8)
Question 21.
Analyse the illustration and answer the following questions.
a) Identify A and B.,
b) How does the deficiency of Vitamin A influence the activity of’B’?
c) Explain why the prolonged deficiency of Vita¬min A leads ultimately to blindness.
Answer:
(a) A:Opsin B: Rhodopsin
(b) The deficiency of vitamin A results in the low • production of retinal. This in turn create the de-ficiency of rhodopsin in rod cells.
(c) Due to the prolonged deficiency of Vitamin A, the conjunctiva and cornea will become dry and opaque. This causes xerophthalmia and leads ultimately to blindness.
Question 22.
Observe the following picture and answer the ques-tions.
a) Name the part labelled ‘X.
b) Mention an two hormones produced by ‘X’ and any one function of each.
c) How does the part labelled T prolongs the body activities for more time, when the sympathetic system gets stimulated?
Answer:
(a) Adrenal cortex
(b) Any two
i. Cortisole
- The synthesis of glucose from protein and fat.
- Controls inflammation and allergy.
- Slows down the action of defense cells.
(Any one)
ii. Aldosterone
- Maintains the salt – water level in the body.
- Maintains blood pressure. (Anyone)
Question 23.
Redraw the given picture and label the parts indi¬cated below. Write any one function for each.
(a) Thalamus
(b) Medulla oblongata
(c) Hypothalamus
Answer:
(a) Thalamus: Acts as relay station of impulses to and from the cerebrum analyse impulses from various parts of the body and sends the impor-tant ones to the cerebrum. (Any one)
(b) Medulla oblongata: Controls involuntary action like heart beat, breathing etc.
(c) Hypothalamus: Plays a major role in the main-tenance of homeostasis.