Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away

Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away English Medium

Select the correct answer.

Question 1.
Hepatitis get transmitted through
a. contact with contaminated water and soil.
b. animals
c. blood components
d. mosquitoes
Answer:
c. blood components

Question 2.
The pathogen of wilt disease of brinjal.
a. Virus
b. Bacteria
c. Fungus
c. Aphids
Answer:
b. Bacteria

Question 3.
Analyse the statements.
i. Filariasis is spread by culex mosquitoes.
ii. Diphtheria is a bacterial disease.
a. (i) correct (ii) incorrect
b. (i) incorrect (ii) correct
c. (i) and (ii) incorrect
d. (i) and (ii) correct
Answer:
d. (i) and (ii) correct

Question 4.
BCG vaccine is used against
a. AIDS
b. Tuberculosis
c. Dengue fever
d. Malaria
Answer:
b. Tuberculosis

Question 5.
Fill up the blanks by observing the relationship between the first pair.
a. AIDS : Through body fluids
Ringworm : …………..
Answer:
Through contact

b. Nipah : Virus
Tuberculosis : …………….
Answer:

Bacteria
c. Block of blood flow in brain : Stroke Deficiency of insulin or its malfunctioning : ……………………
Answer:
Diabetes

Question 6.
Find the odd one out and note down the common features of others.
a. Diabetes, Fatty liver, Heart attack Tuberculosis
Answer:
Tuberculosis
Others are lifestyle diseases.
b. AIDS, Diphtheria, Nipah, Hepatitis
Answer:
Diphtheria
Others are viral diseases.

Question 7.
The symptom of a genetic disease is given below.
Excess blood is lost even through minor wounds
a. Identify the disease..
b. Write the reason for this disease.
c. Write remedy for this disease.
Answer:
a. Haemophilia

b. Blood clots with the help of some proteins present in blood plasma. The synthesis of protein fails when the genes that control protein synthesis become defective.

c. A complete cure is not possible at present. Temporary relief is brought in by injecting the deficient protein identified through clinical diagnosis.

Question 8.
Observe the graph and answer the questions given below.
Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away 1
a. Name the common name for these diseases.
b. Write the cause of each disease.
Answer:
a. Life style diseases.
b.

  • Fatty liver: Deposition of excess fat in the liver.
  • Stroke : Rupture of blood vessels in brain, block of blood flow.
  • Diabetes : Deficiency of insulin or its malfunctioning.
  • Heart attack : Block of blood flow due to the deposition of fat in coronary arteries, which carry blood to heart.

Question 9.
Observe the picture and answer the questions given below.
Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away 2
a. Identify the organism.
b. Which is the disease caused by this organism?
c. What are the ways by which this organism spreads?
Answer:
a. HIV
b. AIDS
c. Through sexual contact with HIV infected person, from HIV infected mother to the foetus, by sharing needle and syringe contaminated with HIV components, through the reception of blood and organs contaminated with HIV.

Question 10.
The symptoms of some diseases are given. Analyse and answer the questions given below.
Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away 3
a. Identify the diseases.
b. Name the pathogens.
c. How are they spread?
Answer:
a. A. Tuberculosis, B. Malaria, C. Ringworm
b.

  • Tuberculosis: Mycobacterium tuberculosis
  • Malaria: Protozoa
  • Ringworm: Fungus

c.

  • Tuberculosis : through air
  • Malaria: through female anopheles mosquito
  • Ringworm : through contact.

Question 11.
Find the indicators related to virus only.
a. No cell organelles as seen in normal cell.
b. There are pathogenic and beneficial ones.
c. Multiply through binary fission.
d. The toxins produced by these damage living cells.
Answer:
a. No cell organelles as seen in normal cell.

Question 12.
What is cancer? How do normal cells get transformed to cancer cells?
Answer:
Cancer is caused by the uncontrolled division of cells and their spread to other tissues. Environmental factors, smoking, radiations, virus, hereditary factors and alternations in genetic material lead to the transformation of normal cells into cancer cells.

Question 13.
Complete the illustration.
Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away 4
Answer:
i. Bacteria
ii. Bunchy top
iii. Fungus
iv. Quickwilt
v. Paddy

Question 14.
Observe the illustration.
Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away 5
a. Identify the disease indicated in the illustration.
b. Write the reason for this disease.
Answer:
a. Sickle cell anaemia.
b. The defects of genes may also cause deformities in the sequencing of amino acids which are the building blocks of haemoglobin. As a result of this, the structure of haemoglobin changes.

Question 15.
Observe the graph , illustrating the data of the diseases affected by the plants ¡n Ravi farm. Analyse the graph and answer the given questions.
Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away 6
a. Identify the plants which are affected.
b. Which is the most affected crop?
c. Note down the causative organism of each disease.
Answer:
a.

  • Blight – Paddy –
  • Bunchy top – banana
  • Quick wilt – pepper
  • Bud rot – coconut

b. Coconut

c.

  • Blight – Bacteria
  • Bunchy top – Virus
  • Quickwilt, Bud rot – Fungus

Question 16.
Select the statement related to Athlete’s foot from the statements given below.
a. Fungal disease.
b. Appearance of reddish scaly rashes that cause itching is the major symptom.
c. Bacterial disease.
d. Manifests as round red blisters on the skin.
e. Pathogens enter through the toes when they come in contact with contaminated water and soil.
Answer:
a. Fungal disease.
b. Appearance of reddish scaly rashes that cause itching is the major symptom.
e. Pathogens enter through the toes when they come in contact with contaminated water and soil.

Question 17.
The symptom of a disease is given below.
The pathogen multiplies using the genetic mechanism of lymphocytes and the number of lymphocytes decreases considerably and reduces the immunity of the body.
a. Identify the disease.
b. Identify the pathogen.
c. Explain how this disease does not spread.
Answer:
a. AIDS
b. HIV
c.

  • By touch, shaking hands, coughing, sneezing, etc.
  • Through insects like mosquitoes, houseflies, etc.
  • By staying together and sharing food.
  • By using same toilets.
  • By taking bath in the same pond.

Question 18.
Observe carefully the graph, illustrating the data of a survey conducted in certain areas. Analyse the graph and answer the given questions.
Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away 7
a. Which type of mosquito dominates in town B?
b. Identify the disease which is likely to be spread in town A. Name the pathogen which causes the disease.
c. Write an important symptom of this disease.
Answer:
a. Anopheles mosquito
b. Filariasis, filarial worms
c. Swelling in the lymph ducts in the leg

Question 19.
How does smoking affect the following body parts?
a. Brain
b. Lungs
Answer:
a. Brain – Stroke, addiction to nicotine
b. Lungs – Lung cancer, emphysema, bronchitis

Question 20.
Choose the diseases transmitted through mosquitoes from the following.
Tuberculosis, Diabetes, Dengue fever, Chicken pox, Chikungunya, Botulism, Malaria, Cholera
Answer:
Dengue fever, Chikungunya, Malaria

Question 21.
Rearrange columns B and C suiting the pictures in column A.
Kerala SSLC Biology Chapter 4 Questions Keeping Diseases Away 8
Answer:
i. b,R
ii. c,P
iii.a,Q

Kerala SSLC Biology Chapter Wise Questions and Answers

Kerala SSLC Biology Chapter 3 Questions Chemical Messages for Homeostasis

Kerala SSLC Biology Chapter 3 Questions Chemical Messages for Homeostasis English Medium

Select the correct answer.

Question 1.
Location of adrenal gland
a. Below thalamus
b. In the scrotum
c. Above the kidneys
d. Just below the sternum
Answer:
c. Above the kidneys

Question 2.
The normal level of glucose in blood
a. 80 – 130 mg/100 ml
b. 70 – 110 mg/100 ml
c. 9-11 mg/100 ml
d. 60 – 100 mg/100 ml
Answer:
b. 70-110 mg/100 ml

Question 3.
The ‘Youth hormone ’ is
a. Thymosin
b. Epinephrine
c. Melatonin
d. Oxytocin
Answer:
a. Thymosin

Question 4.
The hormone in gaseous form
a. Auxin
b. Ethylene
c. Gibberellins
d. Cytokinin
Answer:
b. Ethylene

Question 5.
Fill up the blanks by observing the relationship between the first pair.
a. Calcium : Calcitonin
Glucose : …………………
b. Breaks up stored food : Gibberellins. Promoting the growth of terminal buds : ………………….
c. Norepinephrine : Medulla Aldosterone : ………………..
Answer:
a. Insulin
b. Auxin
c. Cortex

Question 6.
Find out the odd one and note down the common features of others.
a. Cortisol, Aldosterone, Epinephrine,Sex hormones.
b. TSH, ACTH, GTH, ADH
c. Cretinism, Gigantism, Dwarfism, Acromegaly
Answer:
a. Epinephrine
Others are produced by the cortex of adrenal glands.
b. ADH
Others are tropic hormones.
c. Cretinism
Others are related to the production of somatotropin.

Question 7.
The quantity of urine excreted by a person in different seasons is given below. Analyze it and answer the following questions.
Kerala SSLC Biology Chapter 3 Questions Chemical Messages for Homeostasis 1
a. Which is the coldest season?
b. Which hormone is responsible for the variation in quantity of urine?
c. How does this hormone regulate the water level of the body?
Answer:
a. Season 3
b. Vasopressin (ADH)
c. If the production of vasopressin decreases, the reabsorption of water in kidneys decreases. As a result. the quantity of water level in urine increases.

Question 8.
Given below is an incomplete table showing reproduction related both’ changes, controlling hormones, their glands and functions. Fill the missing gaps.

Hormone Gland Function
Progesterone a Maintenance of embryo
b Ovary Growth of sex organs
Testosterone C d
Prolactin e f
g h Facilitating child

Answer:
a. Ovary
b. Oestrogen
c. Testis
d. Sperm production, controls secondary sexual characters in males such as change in voice, growth of hair, etc.
e. Pituitary gland
f. Production of milk
g. Oxytocin
h. Hypothalamus

Question 9.
All hormones do not act upon all cells. Why?
Answer:
Hormones reach every cell in the body as they are transported by blood. But each hormone acts only upon those cells which have specific receptors. The cells which are acted upon by hormones are their target cells

Question 10.
What are the functions of thyroxine? How do the abnormalities in the production of thyroxine affect the body?
Answer:

  • Functions of thyroxine – Raises the rate of metabolism, accelerates the growth and development of the brain in the foetal stage and infancy, increases energy production, regulates growth in children.
  • The deficiency of thyroxine during the foetal stage or infancy – cretinism.
  • Lack of thyroxine in adults – myxoedema.
  • The condition in which all life activities controlled by thyroxine are accelerated due to the excessive production of thyroxine – hyperthyroidism.

Question 11.
Select the answers for the statements from the box given below.
Auxin, Gibberellins, Ethylene, Cytokinin,
Abscisic acid
a. Helps in the ripening of fruits.
b. Helps to sustain the plant in adverse conditions.
c. Promotes cell growth and differentiation.
d. Breaks up stored food.
e. Cell growth, cell elongation, promoting the growth of terminal buds
Answer:
a. Ethylene
b. Abscisic acid
c. Cytokinin
d. Gibberellins
e. Auxin

Question 12.
Identify the disease. Write the reason for this.
Kerala SSLC Biology Chapter 3 Questions Chemical Messages for Homeostasis 2
Answer:
Goitre.
Iodine is essential for the production of thyroxine. The production of thyroxine is obstructed in the absence of iodine. In an attempt to produce more thyroxine, the thyroid gland enlarges.

Question 13.
Find out the peculiarities of column A and rearrange columns B and C.

A B C
Oxytocin Parathyroid Prevents the rise of calcium
Prolactin Thyroid Facilitates lactation
Parathormone Hypothalamus Production of milk
Pituitary Prevents the lowering of calcium

Answer:

  • Oxytocin – Hypothalamus – Facilitates lactation
  • Prolactin – Pituitary – Production of milk
  • Parathormone – Parathyroid – Prevents the lowering of calcium

Question 14.
Hints related to a patient are given below.
Analyze and answer the questions given below.

  • The blood glucose level is more than normal level.
  • Always tired
  • The production of insulin is normal in his body.

a. Identify the disease.
b. Write the reason for this disease.
c. How is the disease related to tiredness?
Answer:
a. Diabetes
b. Malfunctioning of insulin.
c. Insulin enhances cellular uptake of glucose molecules. If the insulin is malfunctioned, it cannot perform this function. The glucose level in cell decreases leading to low energy production. So he feels tired.

Question 15.
Observe the illustration.
Kerala SSLC Biology Chapter 3 Questions Chemical Messages for Homeostasis 3
Complate A,B,C,D,E
Answer:
A. Cortex
B. Norepinephrine
C. Aldosterone
D. Sex hormones
E. Cortisol

Question 16.
“Isn’t this merely a storage and distribution centre? Is it sensible to call this a gland?” This is a doubt raised by Hari, pointing to a particular portion of a gland in the picture of the brain.
a. Which part of which gland may be the basis of Hari’s doubt?
b. Why does Hari have such a doubt? Is his doubt genuine? Why?
Answer:
a. Pituitary – Posterior lobe
b. Sensible. The hormone produced by hypothalamus is stored and released from here. The posterior lobe of pituitary itself does not produce hormone.

Question 17.
Use of artificial plant hormones contributed a lot to the progress of the agricultural sector.
Justify this statement.
(Hints: Artificial gibberllins, artificial abscisic acid, Ethylene)
Answer:
Artificial gibberllins – It is used for increasing fruit size in grapes and apple and also for preventing ripening of fruits to assist marketing.

Artificial abscisic acid – It is used for harvesting fruits at the same time.
Ethylene- Ethylene is used for the flowering of pineapple plants at a time and for the ripening of tomato, lemon, orange, etc. Ethyphon, a chemical which is available in liquid form, gets transformed into ethylene, when used in rubber trees and it increases the production of latex.

Question 18.
Arrange columns B. C according to the data given in column A.

A B C
Diabetes mellitus Excessive production of somatotropin. Low metabolic rate, hypertension. sleeplessness
Acromegaly Lack of thyroxine Increased appetite and thirst and frequent urination.
Cretinism Decreased production of insulin. High metabolic rate, rise in body temperature.
Production of somatotropin decreases Growth of the bones on face, jaws and fingers.

Answer:

A B C
Diabetes mellittus Decreased production of insulin. Increased appetite and thirst and frequent urination.
Acromegaly Excessive production of somatotropin. Growth of the bones on face, jaws and fingers.
Cretinism Lack of thyroxine Low metabolic rate, hypertension, sleeplessness.

Question 19.
Observe the graph and answer the questions given below.
Kerala SSLC Biology Chapter 3 Questions Chemical Messages for Homeostasis 4
a. Who has the normal level of calcium in blood?
b. Name the hormones which help to regulate the blood calcium level in other persons. Explain the action of these hormones.
Answer:
a. Mini
b.
Raju- The level of calcium in blood is more.
The calcitonin secreted by thyroid gland helps in maintaining the level of calcium in blood by depositing the excess calcium in bones and by preventing the mixing of calcium with blood from the bones.

Jose – The level of calcium in blood is less. The parathormone secreted by parathyroid gland helps in maintaining the level of calcium in blood by the reabsorption of calcium in the blood from kidneys and also prevents the deposition of calcium in bones.

Question 20.
Some hormones are given below. Make them into four pairs. Give reasons for pairing.
Oxytocin, Thyroxine, Insulin, Epinephrine, Vasopressin. Glucagon, Cortisol, Calcitonin
Answer:

  • Oxytocin, Vasopressin – Secreted by hypothalamus
  • Thyroxine, Calcitonin -Secreted by thyroid gland
  • Insulin, Glucagon – Secreted by pancreas.
  • Epinephrine, Cortisol – Secreted by adrenal gland

Question 21.
Manu rubbed strongly across the path of the row of moving ants. All the ants moved in different directions immediately.
a. Which is the substance responsible for this?
b. Write another use of this substance.
Answer:
a. Pheromones
b. Pheromones help in attracting mates, informing the availability of food, determining the path of travel, informing about dangers, etc.

Question 22.
Analyze the illustration and answer the questions.
Kerala SSLC Biology Chapter 3 Questions Chemical Messages for Homeostasis 5
a. What is indicated by A (Write the lobe also)?
b. ‘A’ produces the hormones of same type. Do you agree with this statement ? Why?
Answer:
a. The anterior lobe of pituitary.
b. No. It produces tropic hormones (TSR. ACTh,GTH, STH) and prolactin.

Question 23.
Arrange columns B and C according to the data given in column A.

A B C
Vasopressin Adrenal On either side of trachea, just below the larynx
Cortisol Pituitary Just below the sternum
Thymosin Hypothalamus Above kidneys
Thymus Below thalamus

Answer:

A B C
Vasopressin Hypothalamus Below thalamus
Cortisol Adrenal Above kidneys
Thymosin Thymus Just below the sternum

Question 24.
Arrange the statements suitably ¡n the table given below
a. Low metabolic rate.
b. High metabolic rate
c. Emotional imbalance
d. Increase in body weight
e. Oedema
f. Excessive sweating

Hypothyroidism Hyperthyroidism
.

.

.

.

.

.

Answer:

Hypothyroidism Hyperthyroidism
Low metabolic rate High metabolic rate
Increase in body weight Emotional imbalance
Oedema Excessive sweating

Question 25.
Observe the illustration and answer the question given below
Kerala SSLC Biology Chapter 3 Questions Chemical Messages for Homeostasis 6
a. Identify the hormones indicated by i, ii, iii, iv
b. Write the functions of prolactin and oxytocin.
c. Name the condilion caused by the decreased production of somatotropin?
Answer:
a. i. Vasopressin
ii. Oxytocin
iii. Tropic hormones
iv. Somatotropin
b.

  • Prolactin – Production of milk
  • Oxytocin – Facilitates child birth by stimulating the contraction of smooth muscles in the uterine wall, facilitates lactation,

c. Dwarfism

Question 26.
Some statements related to endocrine system are given below.
A. Hormones are the secretions of endocrine glands.
B. Hormones are transported through lymph.
C. Hormones are transported through blood.
D. All the hormones produced by the endocrine glands are proteins.
a. Choose the correct statement.
b. Imagine that a particular hormone is not entering a particular cell. What may be the reason?
Answer:
a. A.Hormones are the secretions of endocrine glands.
C.Hormones are transported through blood.

b. Receptors of that hormones are not in the cell.

Question 27.
Case sheets of two patients are given below. Analyse them and answer the questions.

Case -1 Case -2
Age – 4 yrs Age – 42 yrs
Mental retardation High metabolic rate
Stunted growth Increased heart beat
Emotional imbalance

a. Which are the diseases whose symptoms are indicated above?
b. Write the reasons for the diseases.
Answer:
a. Case – 1 Cretinism
Case – 2 Hyperthyroidism

b. Case – 1
Deficiency of thyroxine during foetal stage and infancy.
Case – 2
Excessive production of thyroxine.

Question 28.
Observe the diagram of the endocrine gland given below and answer the questions.
Kerala SSLC Biology Chapter 3 Questions Chemical Messages for Homeostasis 7
a. Name the parts indicated as A and B.
b. Name the hormones synthesized by A. Explain their action.
Answer:
a. A-Medulla B – Cortex
b. Epinephrine, Norepinephrine
Epinephrine – Helps to tide over emergency situations.
Norepinephrine – acts along with epinephrine.

Question 29.
Analyse the statements given below and write the reason.
a. Oxytocin is injected in pregnant women during child birth (delivery).
b. Feels sleepy during night, wakes up when day breaks.
Answer:
a. Facilitates child birth by stimulating the contraction of smooth muscles in the uterine wall.
b. When the level of melatonin increases at night, we feel sleepy. We wake up when the level of melatonin decreases during the day.

Question 30.
A farmer named Balan cultivated oranges in his orchard. Now the trees are full of oranges. The price of oranges is Rs. 80/kg.
A. This farmer wants to harvest all fruits together.
B. Ripen them together.
a. Suggest two artificial plant hormones to satisfy the A, B needs of the farmer.
b. Uncontrolled use of plant hormones must
be controlled. Evaluate this statement.
Answer:
a. A – Abscisic acid.
B – Ethylene
b.

  • Control uncontrolled use.
  • Environmental issues.
  • Health issues.

Question 31.
Indicators related to the endocrine glands are given below. Analyse them and answer the questions.

  • Situated just below the sternum.
  • Active during infancy.

But constricts at puberty.
a. Name this endocrine gland.
b. Which is the hormone synthesised by this gland?
c. Write the function of this hormone.
Answer:
a. Thymus gland
b. Thymosin
c. Controls the activities and maturation of lymphocytes which help to impart immunity.

Kerala SSLC Biology Chapter Wise Questions and Answers

Kerala SSLC Biology Chapter 5 Questions Soldiers of Defense

Kerala SSLC Biology Chapter 5 Questions Soldiers of Defense English Medium

Question 1.
The vitamin that helps in blood clotting
a. Vitamin A
b. Vitamin B
c. Vitamin C
d. Vitamin K
Answer:
d. Vitamin K

Question 2.
The normal temperature of human body
a. 36° C
b. 37° C
c. 38° C
d. 39° C
Answer:
b. 37° C

Question 3.
The white blood cell that stimulates other white blood cells
a. Neutrophil
b. Basophil
c. Eosinophil
d. Monocyte
Answer:
b. Basophil

Question 4.
The equipment used to record the electric waves in brain.
a. EEG
b. ECG
c. CT Scan
d. BCG
Answer:
a. EEG

Question 5.
Fill up the blanks by observing the relationship between the first pair.
a. To get the three-dimensional visuals of internal organs: MR scanner
To record the electric waves in heart muscle: ………………….
b. Vaccine: Edward Jenner
Antibiotic: ………………….
c. Cardiology: Treatment of heart
Ophthalmology: ………………….
Answer:
a. Electrocardiogram
b. Alexander Fleming
c. Treatment of eye.

Question 6.
Find the odd one out and note down the common features of others.
a. Inflammatory response, Phagocytosis, Fever, Production of antibodies
b. Allopathy, Ayurveda, Antibiotics, Unani
c. Sphygmomanometer, Electrocardiogram, E.N.T, E.E.G
Answer:
a. Production of antibodies. The others are nonspecific defense.
b. Antibiotics. The others are various treatment methods.
c. E.N.T. The others are modem diagnostic tools.

Question 7.
A person felt reduced level of vitamin in his body who takes some medicines for fever without consulting a doctor.
a. What type of medicine may be used by this person?
b. What are the side effects of using them? Explain the reason.
Answer:
a. Use of antibiotics
b. Though antibiotics are effective medicines, their regular use brings many side effects. Some important side effects of regular use are it develops immunity in pathogens against antibiotics, destroys useful bacteria in the body, reduces the quantity of some vitamins in the body.

Question 8.
What is the role of cuticle, cell wall and callose in defense of plants?
Answer:
Cuticle: The external layer of the epidermis of leaves defends the attack of microorganisms.
Cell wall: A well equipped resistant coat.
Chemical substances such as lignin, cutin, suberin, etc., provide rigidity to the cell wall.
Callose: Prevents the entry of germs which, have crossed the cell wall, through the cell membrane

Question 9.
Sharon hit his head while falling and the head swelled.
a. Is this reaction useful to the body? Why?
b. What is this type of reaction called?
c. How is this reaction helpful in defending diseases?
Answer:
a. Yes. Second level defense.
b. Inflammatory response
c. Blood vessels dilate and white blood cells from the blood vessel reach the wound site. White blood cells destroy the germs.

Question 10.
Observe the picture and answer the question given.
Kerala SSLC Biology Chapter 5 Questions Soldiers of Defense 1
a. Identify the white blood cells indicated by A, B.
b. Write the defense activities of these white blood cells.
Answer:
a.
A – Neutrophil B – Basophil
b.

  • Neutrophil – engulfs and destroys the bacteria produces chemicals that can destroy bacteria.
  • Basophil – stimulates other white blood cells, dilates the blood vessels.

Question 11.
When infection becomes uncontrollable, the body temperature may rise very high.
a. How is this situation known as?
b. Write the reason for the rise in body temperature.
c. How the rise in body temperature controls the infection? –
Answer:
a. Fever
b. The presence of toxins produced by the pathogens stimulates white blood cells, the chemical substances produced by the white blood cells rise the body temperature.
c. The rise in the body temperature reduces the rise of multiplication of pathogens, increases the effect of phagocytosis.

Question 12.
Observe the picture of skin and answer the questions given below.
Kerala SSLC Biology Chapter 5 Questions Soldiers of Defense 2
a. Identify the parts indicated as A, B, C.
b. What is the role of these parts in defense mechanism?
Answer:
a. A – Epidermis B – Sebaceous gland C – Sweat gland
b. A protein called keratin present in the epidermis prevents the entry of germs. Sebum produced by the sebaceous gland makes the skin oily and waterproof. The disinfectants present in the sweat produced by sweat gland destroy the germs.

Question 13.
Complete the flow chart related to inflammation.
Kerala SSLC Biology Chapter 5 Questions Soldiers of Defense 3
Answer:
A: Produces chemical messages.
B: White blood cells reach the wound site through the walls of the capillaries.

Question 14.
Select the suitable statements related to B lymphocytes.
a. Mature in the bone marrow.
b. Stimulate other defense cells of the body.
c. These cells are capable of destroying cancer cells.
d. Neutralise the toxin of the antigens.
Answer:
a. Mature in the bone marrow.
d. Neutralise the toxin of the antigens.

Question 15.
Whichever be the type of germs infected, the initial symptom appears in human body will be the fever. Give reason.
Answer:
Pathogens enter the body. Then the presence of toxins produced by the pathogens stimulate the white blood cells. The chemical substances produced by the white blood cells raise the body temperature. The rise in body temperature reduces the rate of multiplication of pathogens and increases the effect of phagocytosis. So fever is a defense mechanism.

Question 16.
Select the correct pairs.
a. Cardiology – Treatment of heart
b. Ophthalmology – Cancer treatment
c. Chemotherapy – Treatment of disorders of the nervous system.
d. E.N.T – Treatment of ear, nose and throat disorders.
Answer:
a. Cardiology – Treatment of heart
d. E.N.T – Treatment of ear, nose and throat disorders.

Question 17.
Select the statements related to specific defense from the statements given below.
a. Destroys the germs that have entered the body.
b. Sebum is a disinfectant
c. Neutrophil is a phagocyte.
d. Prevents the germs from entering the body.
e. Identifies and destroys pathogens.
f. Neutralises the toxin of the antigens.
Answer:
b. Sebum is a disinfectant
c. Neutrophil is a phagocyte.
d. Prevents the germs from entering the body.

Question 18.
The stages related to phagocytosis are given below. Arrange them in correct order.
a. The pathogens are degenerated and destroyed by the enzymes in lysosome.
b. Engulfs the pathogen in the membrane sac.
c. Phagocytes reach near the pathogens.
d. Membrane sacs combine with the lysosome.
Answer:
c. Phagocytes reach near the pathogens.
b. Engulfs the pathogen in the membrane sac.
d. Membrane sacs combine with the lysosome.
a. The pathogens are degenerated and destroyed by the enzymes in lysosome.

Question 19.
The immunity to disease of a child living in natural environment will be ‘greater than that of a child living in over hygienic environment. Do you agree with this statement? Give reason for this.
Answer:
a. Natural environments increase immunity. More chances to acquaint with antigens and to form antibodies against them in the body. Over hygienic environment leads to reduction in natural immunity.

b. When we avoid situations for the body to make antibodies against antigens, we develop poor immunity.

Question 20.
Given below are the two methods which can be used against diseases.
a. Antibiotics
b. Vaccines
i. What is the major difference between the two?
ii. Give one example for each.
Answer:
i. Antibiotics – Antibiotics are used to resist bacterial diseases.
Vaccines – Used for immunity.
ii. Antibiotics-Penicillin Vaccines – B.C.G

Question 21.
What is the role of calcium, thrombin, and fibrin in blood clotting?
Answer:
Calcium ions- Play a major role in the convention of prothrombin in plasma to thrombin by thromboplastin
Thrombin – Thrombin converts the fibrinogen in the plasma to fibrin.
Fibrin – Blood clot is formed by the entangling of platelets and red blood cells in the fibrin network.

Question 22.
Everyone cannot receive blood from all blood groups. Justify this statement.
Answer:
When a foreign antigen reaches one’s blood, it stimulates the defense mechanism. On receiving unmatching blood, the antigen present in the donor’s blood and the antibody present in the recipient’s blood will react with each other and form a blood clot. Hence, everyone cannot receive blood from alt blood groups.

Question 23.
Observe the given picture and answer the questions given below.
Kerala SSLC Biology Chapter 5 Questions Soldiers of Defense 4
a. Name the defense activity indicated in the illustration.
b. Write the stages of this activity.
Answer:
a. Phagocytosis
b. Phagocytes reach near the pathogens.
Engulfs the pathogen in the membrane sac.
Membrane sac combines with lysosome.
The pathogens are degenerated and destroyed by the enzymes in lysosome.

Question 24.
Write down the correct ones among the following statements related to defense.
a. Specific defense is the mechanism in which monocytes engulf the pathogens.
b. Non-specific defense mechanism is a mechanism that protects us from all pathogens without considering their characteristic features.

c. Lymphocytes are the part of non-specific defense mechanism.
d. T-Lymphocytes destroy cancer cells.
Answer:
b. Non- specific defense mechanism is a mechanism that protects us from all pathogens without considering their characteristic features.
d. T-Lymphocytes destroy cancer cells.

Question 25.
Kerala SSLC Biology Chapter 5 Questions Soldiers of Defense 5
a. Identify A
b. B is a vitamin and C is an enzyme. Name them.
c. How does the lack of B or C affect the consequent chemical process?
Answer:
a. A – Prothrombin
b. B – Vitamin K, C – Thromboplastin
c. Thrombin is not formed Fibrinogen will not be converted to fibrin.

Question 26.
One of the scars of the wound obtained by Binu while playing football remained even after 10 years. What explanation will you give for the scar remaining as such?
Answer:
Connective tissue heals the wound.
New tissues are not formed in the place of damaged tissues.

Question 27.
Ashiq who met with an accident, was in need of blood. Antigen A and D and Antibody b was identified in his blood.
a. Name his blood group?
b. Whose blood, among the following, can be accepted by Ashiq?
i. Venu: A +
ii. Amal: AB+
iii. Sahara: AB-
iv. Anoop: A-
Answer:
a. A+
b. i. Venu : A+
ii. Anoop : A-

Question 28.
Complete the table.

Vaccine Disease
…………. (a)………… Tuberculosis
…………. (b)………… Polio
Pentavalent …………. (c)…………
M.M.R. …………. (d)…………
T.T …………. (e)…………

Answer:
a. B.C.G.
b. O.P.V.
c. Diphtheria, tetanus, pertussis (whooping cough), hepatitis B and Haemophilus influenza type b
d. Measles, mumps, and rubella (German measles)
e. Tetanus

Question 29.
Given below is the picture of white blood cells which are parts of specific defense.
Kerala SSLC Biology Chapter 5 Questions Soldiers of Defense 6
a. Identify A and B.
b. What is the role of A in specific defense?
c. Give any one difference between A and B.
Answer:
a. A – T – lymphocyte B – B lymphocyte

b. Stimulates other defense cells.
Destroys cancer cells and virus affected cells.

c. B – lymphocytes mature at bone marrow.
T – lymphocytes mature at thymus.

Question 30.
What all things should be taken care of while transfusing blood?
Answer:

  • People in the age group 18-60 can donate blood.
  • Blood donation can be done once in three months.
  • Blood donation causes no problem to the donor’s health.
  • Pregnant women and breastfeeding mothers should not donate blood.
  • Persons with communicable diseases (transmitted through blood) should not donate blood.

Question 31.
How do the following situations help in defense activity?
a. Many useful bacteria that habitat in the coverings of the body.
b. Rise in body temperature
c. Antibodies
d. Vaccines
Answer:
a. Coverings of the body act as a habitat for many useful bacteria. The genus that enter the body need to compete with such useful bacteria for shelter and nutrients. A great number of germs get destroyed in this competition.

b. The rise in the body temperature reduces the rise of multiplication of pathogens, increases the effect of phagocytosis.

c. Antibodies destroy the pathogens in three different ways.

  1. Destroy the bacteria by disintegrating their cell membrane.
  2. Neutralise the toxin of the antigens.
  3. Destroy the pathogens by stimulating other white blood cells.

d. Vaccines are the substances used for artificial immunization. Vaccines act as antigens that stimulate the defense mechanism of the body. Antibodies are formed in the body against them. These antibodies are retained in the body which in future protect the body from the pathogen responsible for the same disease.

Kerala SSLC Biology Chapter Wise Questions and Answers

Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries

Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries English Medium

Question 1.
The scientist who has laid the foundation of Genetics
a. Carl Linnaeus
b. Gregor Johann Mendel
c. James Watson
d. Charles Darwin
Answer:
b. Gregor Johann Mendel

Question 2.
The different forms of genes that control the trait,
a. Chromosome
b. Allele
c. Nucleotide
d. Nucleus
Answer:
c. Allele

Question 3.
The genetic constitution of females,
a. 44 + XX
b. 44 + XY
c. 43 + XX
d. 43 + XY
Answer:
a. 44 + XX

Question 4.
The sugar seen in DNA.
a. Ribose
b. Ribosome
c. Ribulose
d. Deoxyribose sugar
Answer:
d. Deoxyribose sugar

Question 5.
Fill up the blanks by observing the relationship between the first pair.
a. DNA: Two strands RNA: …………………..
b. Associated with ribosome: rRNA
Carry amino acids to the ribosome: …………………..
c. TT: tall
tt: …………………..
Answer:
a. Single strand
b. tRNA
c. Dwarf

Question 6.
Find the odd one out, note down the common features of others.
a. TTRR, TtRr, TTRr, ttrr
b. A-T, G-C, T-A, U-A
c. Adenine, Thymine, Guanine, Uracil
Answer:
a. ttrr
Others are tall plant with round seed
b. U-A
Others are nitrogen base pairs in DNA.
c. Thymine
Others are nitrogen bases seen in RNA.

Question 7.
Select the statements related to RNA from the given statements.
a. Has two strands
b. Ribose sugar is seen
c. Do not participate directly in protein synthesis
d. The nitrogen bases are Adenine, Uracil, Cytosine, Guanine
Answer:
b, d

Question 8.
Given below is the illustration showing how sex determination is taking place in human beings.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 1
b. What are the inferences you arrive at from this illustration?
Answer:
a. i. 44 + XX
ii. 44 + XY
iii. 44 + XX
iv. 44 + XY
b. The male and female ratio will be 1:1. The XY chromosomes of the father determine whether the child is male or female.

Question 9.
The stages related to action of gene is given below. Arrange them in correct order.
a. mRNA reaches the ribosome.
b. mRNA reaches outside the nucleus.
c. Protein is synthesized.
d. tRNA carries amino acids to the ribosome.
e. mRNA forms from DNA.
f. Based on the information in mRNA amino acids are added.
Answer:
e, b, a, d, f, c

Question 10.
Observe the illustration and answer the questions given below.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 2
a. Name the illustration.
b. What is its importance?
Answer:
a. Crossing over
b. As a result of this, part of a DNA crosses over to become the part of another DNA. This causes a difference in the distribution of genes. When these chromosomes are transferred to the next generation, it causes the expression of new characters in offspring.

Question 11.
Select the correct statements.
a. 46 chromosomes are seen in humans.
b. 23 pairs of autosomes are found in humans.
c. Genetic constitution of male is 44 + XY.
d. Sex chromosomes are of two types.
e. Genetic constitution of female is 46 + XX.
Answer:
a, c, d

Question 12.
Observe the illustration related to hybridization of two types of pea plants and answer the following questions.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 3
a. Which are the characters expressed in first-generation?
b. Which are the hidden characters in this experiment?
c. Write the possible expression of different characters in next generation.
Answer:
a. Round seed, white flower
b. Flat seed, red flower
c. Round seed, white flower Round seed, red flower Flat seed, white flower Flat seed, red flower.

Question 13.
Given below is the illustration of a cross conducted between red-flowered and white-flowered pea plants. Complete it suitably.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 4
a. First-generation
b. Write down the ratio of pea plants with different characters in the second generation.
Answer:
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 5
b. 3 red flowers: 1 white flower

Question 14.
Complete the given illustration of a nucleotide molecule.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 6
Answer:
a. Sugar molecule
b. Phosphate

Question 15.
Complete the flow chart showing gene action.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 7
Answer:
a. mRNA reaches outside the nucleus.
b. mRNA reaches ribosomes.
c. Based on the information in mRNA amino acids are added.

Question 16.
Complete the table suitably.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 8
Answer:
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 9

Question 17.
Observe the illustration and answer the questions given below.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 10
a. What is the dominant and recessive characters in the first generation?
b. If the plants obtained in first-generation is self-pollinated, what are the characters appear in the second generation? In which ratio.
c. Redraw the illustration using letters.
Answer:
a. Dominant character – Tall Recessive character – Dwarf
b. 3 Tall: 1 Dwarf
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 11

Question 18.
Analyze the illustration based on the self-pollination of first-generation.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 12
a. Complete the illustration.
b. Offsprings of second generation. In which ratio?
Answer:
a. 1 – T
2-t
3 – TT
4 – Tt
5 – Tt
6 – tt

b. 3 tall: 1 Dwarf

Question 19.
A pea plant with genetic constitution TtRr (Tall plant producing round seed) was subjected to self-pollination. The genetic constitution of some of the progenies obtained are given below. Write the expressed character of the given progenies based on their genetic constitution.
a. TTRr
b. ttRr
c. ttrr
d. Ttrr
Answer:
a. TTRr – Tall plant producing round seed
b. ttRr – Dwarf plant producing round seed.
c. ttrr – Dwarf plant producing wrinkled seed
d. Ttrr – Tall plant producing wrinkled seed

Question 20.
The note prepared by Shahana on Mendel’s inferences during the classroom analysis of Mendel’s hybridization experiment in pea plants, based on a single trait is given below. Analyse the statements in the note and correct those that are wrong ones.
a. A trait is controlled by a specific factor.
b. A character is expressed and the other remains hidden in the first generation.
c. The character that remains hidden in the first generation does not appear in the second generation.
d. The ratio of characters in the second generation is 3:1.
Answer:
a. One trait is controlled by the combination of two factors.
c. The character that remains hidden in the first generation appears in the second generation.

Question 21.
Complete the flowchart illustrating the location of gene by using the information given in the box:
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 13
Answer:
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 14

Question 22.
Observe the illustration given below and answer the questions.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 15
a. Identify the dominant character.
b. How does the parental plant with green-colored seed and the plant in the first generation differ in their alleles?
c. Describe alleles.
Answer:
a. Green
b. Alleles in parental plant-QG Allele in the first generation – Gg
c. Different forms of a gene.

Question 23.
Observe the nucleotide strands given below and answer the questions. ‘
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 16
a. Identify the strand that is found in DNA only.
b. Identify the strand that can be found in both DNA and RNA.
c. What is a nucleotide?
Answer:
a. B
b. A
c. A unit of sugar, phosphate, and nitrogen base/ Component of nucleic acid.

Question 24.
Given below is an illustration regarding sex determination. Observe the illustration and answer the questions.
Kerala SSLC Biology Chapter 6 Questions Unravelling Genetic Mysteries 17
a. Complete A, B, C in the illustration.
b. What is the possibility of the formation of a male child or a female child? Explain.
Answer:
a.
A. 44 + XY
B. 22 + X
C. 22 + Y
b. Equal chance. The number of male gametes with X chromosome and those with Y chromosome are equal. Egg with the X chromosome has equal chance to combine with sperm having Y chromosome and those having X chromosome.

Question 25.
Given below is a placard exhibited in a school rally organised ‘Against Racism ’.
It is not racial difference that makes the skin colour different; This is an adaptation to live under the sun.
a. How will you explain the difference in skin colour of people living in different parts of the world?
b. What attitude should be adopted by a scientifically enlightened society towards the idea in the placard? Substantiate.
Answer:
a. Melanin, a pigment protein imparts colour to skin.
It is due to the difference in gene function.

b. Skin colour is an adaptation to live under the sun.

  • Races among mankind are only cultural.
  • Scientifically, all men are of the same race.
  • Consider all men as equal, without any racial difference.

Question 26.
‘Gene itself is allele; allele itself is gene Substantiate your answer.
Answer:
Statement is partly correct. Each character is controlled by pair factors called genes. Different forms of a gene are called alleles. Generally, a gene has two alleles. Alleles can be of the same types (TT) or of different types (Tt). If the alleles are of different types, only one trait represented by any one of the alleles get expressed.

Question 27.
In the hybridization experiment conducted by Mendel on the basis of two contrasting traits of the character height in pea plant
a. In the first generation, tall plants are expressed. No dwarf plant is seen in the first generation.
b. The dwarf plants were expressed in second generation. Give explanation.
Answer:
a. When plants that differ in a pair of contrasting traits are hybridized, only one trait is expressed while the other remains hidden in the offsprings of the first generation. The expressed trait is called dominant trait and the hidden trait is called recessive trait.
b. During gamete formation the factors that determine height segregate without getting mixed. This is the reason for the expression of the dwarf plants in second generation.

Kerala SSLC Biology Chapter Wise Questions and Answers

Kerala SSLC Biology Chapter 1 Questions Sensations and Responses

Kerala SSLC Biology Chapter 1 Questions Sensations and Responses English Medium

Select the correct answer.

Question 1.
The tip of axonite
a. Axon
b. Dendron
c. Synaptic knob
d. Dendrite
Answer:
c. Synaptic knob

Question 2.
In spinal cord
a. white matter outside and grey matter inside ”
b. white matter on outside and inside
c. grey matter on outside and inside
d. white matter inside and grey matter outside
Answer:
a. white matter outside and grey matter inside

Question 3.
The part of brain which plays a major role in the maintenance of homeostasis.
a. Thalamus
b. Hypothalamus
c. Cerebrum
d. Medulla oblongata
Answer:
b. Hypothalamus

Question 4.
Read the statements given below.
i. The part where myelinated neurons are present in abundance is called white matter.
ii. Nerves are groups of dendrites covered by connective tissue.
a. i and ii correct
b. i and ii wrong
c. i wrong ii correct
d. i correct ii wrong
Answer:
d. i correct ii wrong

Question 5.
Fill up the blanks by observing the relationship between the first pair.
a. SoundExternal stimulus : : Hunger : …………………
b. Spinal nerves : 31 pairs : : Cranial nerves …………………
c. Sensory impulses reach the spinal cord : Dorsal root: : Motor impulses go out of the spinal cord : ………………..
Answer:
a. Internal stimulus
b. 12 pairs
c. Ventral root

Question 6.
Find out the odd one and note down the com-mon features of others.
a. Alzheimer’s, Tuberculosis, Parkinson’s, Epilepsy
b. Dendron, Axon, Nephron, Dendrite
c. Thought, maintains equilibrium, memory, imagination
Answer:
a. Tuberculosis
Others are diseases affecting nervous system
b. Nephron. Others are parts of neuron
c.

  • Maintains equilibrium
  • Others are functions of cerebrum

Question 7.
Explain the differences between axons and dendrons.
Answer:
Axons and dendrons are projections from the cyton (cell body). Axons are the longest filament from the cell body and dendrons are the short filament from the cell body. Dendrites are the branches of dendron and branches of axons are axonites. Dendron carries impulses from dendrites to the cell body while axon carries impulses from the cell body to outside. Axon is encircled by myelin sheath.

Question 8.
Complete the table suitably.

Nerve Function
Sensory nerve (a)
(b) Carries impulses from brain and spinal cord to various parts of the body.
(c) (d)

Answer:
a. Carries impulses from various parts of the body to the brain and the spinal cord.
b. Motor nerve
c. Mixed nerve
d. Carries impulses to and from the brain and spinal cord.

Question 9.
Select the correct pairs.
a. Axonite – secretes neurotransmitter
b. Schwann cell – encircles the axon
c. Axonite – branches of dendron
d. Axon – carries impulses from the cell body to outside
e. Synaptic knob – secretes neurotransmitter
Answer:
b. Schwann cell – encircles the axon
d. Axon – carries impulses from the cell body to outside
e. Synaptic knob – secretes neurotransmitter

Question 10.
Arrange columns B, C in accordance with the data given in column A.

A B C
Cerebrum Situated just below the thalamus Maintains equilibrium of the body
Cerebellum The largest part of the brain Plays a major role in the maintenance of homeostasis
Hypothalamus Seen behind the cerebrum as two flaps Centre of thought, imagination and intelligence

Answer:

A B C
Cerebrum The largest part of the brain Centre of thought, imagination and intelligence
Cerebellum Seen behind the cerebrum as two flaps Maintains equilibrium of the body.
Hypothalamus Situated just below the thalamus Plays a major role in the maintenance of homeostasis

Question 11.
The cause of a disease affecting the nervous system is given below.
Continuous and irregular flow of electric charges in the brain
a. Identify the disease.
b. Write the symptoms.
Answer:
a. Epilepsy
b. Fits due to continuous muscular contraction, frothy discharge from the mouth, clenching of teeth following which the patient falls unconscious.

Question 12.
Observe the illustration and answer the questions given below.
a. Identify the part indicated as A.
b. How is this part formed?
c. Write the functions of this part.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 1
Answer:
a. A – Myelin sheath.
b. Schwann cells repeatedly encircle the axons to form the myelin sheath.
c. To provide nutrients and oxygen to the axon, accelerate impulses, act as an electric insulator and protect the axon from external shocks.

Question 13.
Rajesh ate his food while watching the hairraising scenes of a film on TV. Will this affect hi’s digestion? Formulate an inference related to sympathetic-parasympathetic actions. List out the facts which led you to the inference.
Answer:
Adversely affects digestion.
Sympathetic system gets stimulated in such situations. So secretion of saliva decreases, peristalsis slows down and functions of the stomach slow down in this situation.

Question 14.
a. What are the parts of the central nervous system?
b. What are the parts included in the peripheral nervous system?
c. How does the brain communicate with organs?
d. How does the spinal cord communicate with organs?
e. Complete the flowchart of nervous system.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 2
Answer:
a. Brain and spinal cord
b. Peripheral nervous system includes 12 pairs of cranial nerves, 31 pairs of spinal nerves and sympathetic and parasympathetic systems of autonomous nervous system.
c. Brain communicates with the organs by 12 pairs of cranial nerves.
d. Spinal cord communicates with the organs by 31 pairs of spinal nerves.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 3

Question 15.
The diagram below shows neuron and the direction of nerve impulse through it. Observe the diagram and answer the questions.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 4
a. If there is a mistake in the direction of nerve impulse, redraw the diagram and correct it.
b. How does the impulse pass through the part X?
Answer:
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 5
b. When electric impulses from the axon reach the synaptic knob, certain chemical substances are secreted from there to the synaptic cleft. These chemical substances are called neurotransmitters. They stimulate the adjacent dendrite or cell and new electric impulses are generated.

Question 16.
Observe the figure and answer the questions given below.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 6
a. Identify the figure.
b. Identify the parts A, B and C.
c. Write the functions of part indicated as A and B.
d. Write the peculiarity of part indicated as C.
Answer:
a. Spinal cord
b. A – Dorsal root B – Ventral root C – Central canal
c. Dorsal root – Sensory impulses reach the spinal cord through the dorsal root.
Ventral root – Motor impulses go out of the spinal cord through the ventral root.
d. Filled with cerebrospinal fluid.

Question 17.
Select the answer for the statements from the box given below.
Thalamus, Synaptic knob, Spinal cord, Dendrite, Axonite, Medulla oblongata

a. Secretes neurotransmitter.
b. Carries impulses to the synaptic knob.
c. Branches of dendron.
d. Acts as relay station of impulses.
e. Controls involuntary actions
f. Coordinates the rapid and repeated movements during walking, running.
Answer:
a. Synaptic knob
b. Axonite
c. Dendrite
d. Thalamus
e. Medulla oblongata
f. Spinal cord

Question 18.
Arrange the statements suitably.
a. Trachea dilates
b. Glycogen is converted to glucose.
c. Production of hormone increases.
d. Urinary bladder contracts
e. Production of saliva increases.
f. Peristalsis in the intestine slows down
g. Heartbeat increases.
h. Glucose is converted to glycogen.

Sympathetic system Parasympathetic system
.

.

.

.

Answer:

Sympathetic system Parasympathetic system
Glycogen is converted to glucose. Trachea dilates
Production of hormone increases. Urinary bladder contracts
Peristalsis in the intestine slows down. Production of saliva increases
Heartbeat increases Glucose is converted to glycogen.

Question 19.
The symptoms of a disease affecting the nervous ’ system are given below.
Loss of body balance, irregular movement of muscles, shivering of the body, profuse salivation
a. Identify the disease.
b. Write the causes of this disease.
Answer:
a. Parkinson’s
b. Destruction of specialised ganglions in the brain, production of dopamine reduces.

Question 20.
Redraw the picture of brain and identify and label the parts based on the statements given below.
a. Centre of thought, intelligence, memory and imagination.
b. The part which controls involuntary actions.
c. The part which coordinates muscular activities and maintains equilibrium of the body.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 7
Answer:
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 8
a. Cerebrum
b. Medulla oblongata
c. Cerebellum

Question 21.
Observe the figure and answer the questions given below.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 9
a. Identfy the parts indicated as A, B, C.
b. How are the parts indicated by A and B structurally different?
c. What are the functions of part indicated as C?
Answer:
a. A – Cerebrum B – Cerebellum
C – Medulla oblongata
b

  • Cerebrum – the largest part of the brain, numerous fissures and folds are seen.
  • Cerebellum – the second largest part of brain, fissures and grooves are present.

c. Medulla oblongata controls involuntary actions like heartbeat, breathing. etc.

Question 22.
Arrange columns B and C in accordance with the data given in A.

A B C
Axon Tip of the axonite Part which receives impulses from the adjacent neuron
Synaptic knob Branches of dendron curries impulses from the cell body lo outside
Dendrite Longest filament from the cell body Secretes neurotransmitter

Answer:

B

A B C
Axon Longest filament from the cell body Carries impulses from the cell body to outside
Synaptic knob Tip of the axonite Secretes neurotransmitter
Dendrite Branches of dendron Part which receives impulses from the adjacent neuror

Question 23.
Radha is moving away with fear from a snake.
a. State what happens to the functioning of following organs?

  • Heart
  • Pupil
  • Trachea
  • Liver

b. Which nervous system is activated during such emergency situations?

Answer:

a.

  • Heart – Heart beat increases
  • Pupil – The pupil in the eye dilates
  • Trachea – Trachea dilates
  • Liver – Glycogen is converted to glucose

b. Sympathetic system

Question 24.
Myelin sheath in the brain and the spinal cord is formed of specialized cells called ………………….
Answer:
oligodendrocytes.

Question 25.
The thalamus is the post office of the brain. Evaluate this statement based on the function of thalamus.
Answer:
Thalamus analyses impulses from various parts of the body and sends the important ones to cerebrum. Thalamus also acts as relay station of impulses to and from the cerebrum.

Question 26.
Segregate the following statements suitably.
a. Covered by meninges
b. Connected to different parts of body through 31 pairs of nerves
c. Part of central nervous system
d. Filled with cerebrospinal fluid
e. Filled with aqueous fluid
f. Consists of 12 pairs of nerves
g. Centre of consciousness
h. All are mixed nerves
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 10
Answer:
A – f, g
B – b, h
C – a, c, d
D – e

Question 27.
How is the brain protected?
Answer:
The brain is protected inside a hard skull. Brain is covered by the meninges, a three-layered membrane. The cerebrospinal fluid is filled within the inner membranes of meninges and the ventricles of the brain help to protect the brain from injuries.

Question 28.
How does sympathetic system act on the ‘ following organs?

  • Liver
  • Heart
  • Stomach

Answer:

  • Liver – Glycogen is converted to glucose.
  • Heart – Heartbeat increases
  • Stomach – Gastric activities slow down.

Question 29.
Complete the flow chart.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 11
Answer:
A – Sensory neuron – carries impulses to the spinal cord
B – Motor neuron – carries the information from spinal cord to related muscles.

Question 30.
Observe the figure and answer the questions given below.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 12
a. Identify the part indicated as A.
b. Explain the role of the part in the transmission of impulses from one neuron to another.
Answer:
a. Synapse .
b. The electric impulses generated by stimuli reach the synaptic knob where certain chemical substances are secreted. The chemical substance (neurotransmitter) which is released in the synaptic cleft stimulates the adjacent dendrite and new electric impulses are formed.

Question 31.
Complete the flow chart.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 13
Answer:
a. Dendrite
b.Axon
c. Synaptic knob
d. Synapse

Question 32.
Observe the figure and answer the following questions.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 14
a. What is indicated in the diagram?
b. What are the peculiarities of this, common to that of brain?
Answer:
a. Spinal cord
b. Covered with meninges and filled with cerebrospinal fluid

Question 33.
Analyze the illustration and answer the questions.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 15
a. What is indicated in the illustration?
b. A and B are neurons. Write their difference.
c. Write an example related to this illustration.
Answer:
a. Reflex action
b. A – Sensory neuron
Carries impulses to the spinal cord . B – Motor neuron
Carries the information from the spinal cord to related muscles.
c. Hand is withdrawn while touching fire.

Question 34.
The brain contains a fluid which is formed from and reabsorbed into the blood.
a. Identify the fluid.
b. What are the functions of that fluid?
Answer:
a. Cerebrospinal fluid
b. Provides nutrients and oxygen to brain tissue, protects the brain from injuries

Question 35.
One of the components of the nervous system is illustrated below. Fill in the blanks appropriately.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 16
Answer:
a. Cranial nerves
b. 31 pairs
c. Autonomous nervous system
d. Sympathetic system

Question 36.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 17
The causes of diseases related to the nervous system in two individuals X and Y are given above.
i. Identify the diseases.
ii. The deficiency of which neurotransmitter causes disease in Y?
Answer:
i. X-Alzheimer’s Y – Parkinson’s
ii. Dopamine

Question 37.
Analyse the illustration of impulse transmis¬sion through axon and answer the following questions.
Kerala SSLC Biology Chapter 1 Questions and Answers Sensations and Responses 18
a. What are the changes that take place in illustration B when compeared to A? Give reasons for this change.
b. Explain how this change brings about the transmission of impulses through axon.
Answer:
a. When stimulated, ionic equilibrium in the particular part changes, and the outer surface of the plasma membrane of axon becomes negatively charged while the inner surface becomes positively charged.

b.

  • These changes generate impulses.
  • The momentary charge difference in the axon stimulates its adjacent parts.
  • Similar changes occur there also.
  • Impulses get transmitted through axon

Question 38.
Mohan lost his memory and was partially paralysed after he met with an accident.
a. Which part of Mohan’s brain was affected?
b. How is the brain protected?
Answer:
a. Cerebrum
b.

  • Skull
  • Meninges
  • Cerebrospinal fluid

Question 39.
Identify the correct statements from those given below.
i. The central nervous system consists of the brain and the spinal cord.
ii. The peripheral nervous system consists of 31 pairs of cranial nerves and 12 pairs of spinal nerves.
iii. The sympathetic system and the parasym-pathetic system are parts of the central nervous system.
iv. The autonomous nervous system which is a part of the peripheral nervous system helps to overcome the emergency situations.
Answer:
i. The central nervous system consists of the brain and the spinal cord,
iv. The autonomous nervous system which is a part of the peripheral nervous system helps to overcome the emergency situations.

Question 40.
Balu :
In the spinal cord and the cerebrum , white matter is seen outside and grey matter is seen inside.

Ramu :
In the cerebrum, the grey matter is seen outside and the white matter is seen inside, But in the spinal cord, the white matter is seen outside and the grey matter is seen inside.
In the group discussion related to the nervous system, Balu and Ramu said so.
a. Whose opinion do you agree with?
b. Explain white matter and grey matter.
Answer:
a. Ramu’s opinion
b.

  • White matter
    The part of the brain and the spinal cord where myelinated nerve cells are present in abundance.
  • Grey matter.
    The part where non-myelinated nerves cells are present is called grey matter.

Kerala SSLC Biology Chapter Wise Questions and Answers

Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge

Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge and Responses English Medium

Select the correct answer.

Question 1.
The transparent anterior part of sclera
a. Conjunctiva
b. Cornea
c. Iris
d. Pupil
Answer:
b. Cornea

Question 2.
The liquid which helps in maintaining the shape of eye
a. Aqueous humour
b. Cerebrospinal fluid
c. Tears
d. Vitreous humour
Answer:
d. Vitreous humour

Question 3.
The visual pigment in rod cells
a. Rhodopsin
b. Retinal
c. Photopsin
d. Iodopsin
Answer:
a. Rhodopsin

Question 4.
The part that connects middle ear and pharynx
a. Oval window
b. Eustachian tube
c. Round window
d. Tympanum
Answer:
b. Eustachian tube

Question 5.
Fill up the blanks by observing the relationship between the first pair.
a. Planaria : Eyespot :: House fly : ……………..
b. Cochlea : Hearing :: Vestibule : ……………
c. The outer layer made up of connective tissues : Sclera :: The inner layer which has photoreceptors : ………………….
Answer:
a. Ommatidia
b. Body balancing
c. Retina

Question 6.
Find out the odd one and note down the common features of others.
a. Sclera, Choroid, Optic nerve, Retina ‘
b. Pinna, Malleus, Incus, Eustachian tube
c. Vestible, Semicircular canals, Iris, Vestibular nerve
Answer:
a. Optic nerve
Others are layers of eye.
b. Pinna
Others are parts of middle ear.
c. Iris
Others are parts related to body balancing.

Question 7.
The ciliary muscles of a person do not contract.
a. How does this affect his vision?
b. Does this affect the action of photoreceptors of retina? Why?
Answer:
a. He cannot see near objects.
b. It does not affect the action of photoreceptors of retina. It is because when light ray reaches the retina, the photoreceptors are stimulated.

Question 8.
The diagram given below shows the structure of ear.
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 1
a. Redraw the picture.
b. Label the parts A, B, C, D.
c. Write down the name and function of E and F.
Answer:
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 2
b. A. Tympanum, B. Auditory nerve, C. Ear ossicles, D. Eustachian tube
c.

  • E-Semicircular canals. It helps in the maintenance of balancing of body.
  • F-Cochlea. Helps in hearing.

Question 9.
Observe the figure and answer the questions given below.
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 3
a. Identify the part labelled as A, B, C, D.
b. Write the peculiarities of part mentioned as A, C.
c. Write the functions of part indicated as B, D.
Answer:
a. A-Cornea, B- Sclera, C-Pupil, D-Optic nerve
b.

  • A-Slightly projected transparent anterior part of the sclera.
  • C – The aperture seen at the centre of the iris. The size increases and decreases depending on the intensity of light.

c.

  • Sclera – Gives firmness to the eye
  • Optic nerve – Transmits impulses from photoreceptors to the visual centre in the brain.

Question 10.
Arrange the statements suitably in the table given below.
a. Ligaments stretch.
b. Focal length decreases.
c. Ciliary muscles relax.
d. Ligaments relax.
e. Ciliary muscles contract.
f. Curvature of lens decreases.
g. Focal length increases
h. Curvature of lens increases.

While viewing near objects While viewing distant objects
.

.

.

.

Answer:

While viewing near objects While viewing distant objects
Focal length decreases Focal length increases
Ligaments relax Ligaments stretch
Ciliary muscles contract Ciliary muscles relax
Curvature of lens increases Curvature of lens decreases

Question 11.
The flowchart related to the process of hearing is given below complete it.
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 4
Answer:
a. Tympanum
b. Ear ossicles
c. Cochlea
d. Auditory nerve
e. Cerebrum

Question 12.
Make suitable word pairs by using the words given in the box.
Jacobson’s organ, Housefly, Eye spot, Snake, Shark, Planaria, Ommatidia, Lateral line
Answer:

  • Snake – Jacobson’s organ
  • Housefly – Ommatidia
  • Shark – Lateral line
  • Planafia – Eye spot

Question 13.
The stages related to maintain the equilibrium of the body are given below. Arrange them in correct order.
a. Generates impulses
b. Maintains the equilibrium of the body
c. Body movements create movement in the fluid inside the vestibule and semicircular canals.
d. The impulses are transmitted by the vestibular nerve.
e. Cerebellum enables muscular movements.
f. Creates movements of the sensory hair cells.
Answer:
c. Body movements create movement in the fluid inside the vestibule and semicircular canals.
f. Creates movements of the sensory hair cells.
a. Generates impulses
d. The impulses are transmitted by the vestibular nerve.
e. Cerebellum enables muscular movements.
b. Maintains the equilibrium of the body

Question 14.
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 5
a. Construct two questions related to this figure and see whether you can give any explanation.
b. Give suitable explanation of the questions.
Answer:
a.

  • Two images from an object are formed in two eyes. But we see only one image of the object. Why?
  • Draw a flow chart of light rays from the object to the centre of vision in brain.

b

  • Two images of the same object formed in the two eyes reach the visual area of the brain. The brain combines the two images together to give a single vision.
  • Light from the object → Eyes → Sensory nerve → Brain → Centre of vision.

Question 15.
“Receptors are modified neurons”. Justify the statement with examples of receptors in different sense organ.
Answer:
Receptors are modified neurons. They are of different types. Rods and cones of eye, sound receptors in ear, taste receptors on the tongue, olfactory receptors in nose and receptors in skin are examples.

Question 16.
Glaucoma is a serious eye defect. Analyze the statement.
Answer:
If the reabsorption of aqueous humour does not occur, it causes an increase in the pressure inside the eyes. This causes damage to the retina and the photoreceptor cells and ultimately leads to blindness.

Question 17.
Arrange columns B and C according ro ¡he daa given in column A.

A B C
Pupil Seen around lens Plenty of photoreceptors are present
Ciliary muscle The part of retina where the optic nerve begins Size of aperture regulated depending on the intensity of light
Blind spot Part of choroid seen behind the cornea The contraction and relaxation of these alter curvature of lens
The aperture seen at the centre of the iris. Photoreceptors are absent

Answer:

A B C
Pupil The aperture seen at the centre of the iris. Size of aperture regulated depending on the intensity of light
Ciliary muscle Seen around lens The contraction and relaxation of these alter curvature of lens ,
Blind spot The part of retina where the optic nerve begins Photoreceptors are absent

Question 18.
Observe the figure and answer the questions given below.
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 6
a. Identify the situation indicated by the figure.
b. Identify the parts indicated as A, B.
c. How do A and B act in the situation?
Answer:
a. While viewing nearby objects
b. A – Ciliary muscles, B – lens
c. The contraction of ciliary muscles and the relaxation of ligaments help to increase the curvature of lens.

Question 19.
Prepare a flowchart related to the sense of vision by selecting suitable words given in the box.

Cornea, Auditory nerve, Blind spot, Aqueous humour. Retina, Eustachian tube, Light, Impulse, Pupil, Choroid, Vitreous humour, Cerebrum, Cochlea, Optic nerve, Sense of vision, Lens
Answer:
Light → Cornea → Aqueous humour → Pupil → Lens → Vitreous humour → Retina → Impulse → Optic nerve → Cerebrum → Sense of vision

Question 20.
Observe the picture and answer the questions – given below.
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 7
a. Identify the picture
b. Identify the parts indicated as A, B, C, D.
c. What are the functions of C, D?
Answer:
a. Internal ear.
b. A- Semicircular canals B – Cochlea C – Autidory nerve D – Vestibular nerve
c.

  • Auditory nerve – Transmits impulses related to hearing to cerebrum.
  • Vestibular nerve – Transmits impulses related to body balancing to cerebellum.

Question 21.
Prepare a flowchart related to the experience of taste.
Answer:
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 8

Question 22.
Find out the peculiarities of column A and rearrange columns B and C.

A

Organs

B

Secretions

C

Functions

Eye Endolymph Excretion of waste and regulation of temperature
Nose Cerebrospinal fluid Protection, nutrition, removal of urea
Ear Aqueous fluid Helps in functioning of olfactory receptors
Skin Mucus Nutrients and oxygen to the tissues
Sweat Transmission of auditory impulses

Answer:

A

Organs

B

Secretions

C

Functions

Eye Aqueous fluid Nutrients and oxygen to the tissues
Nose Mucus Helps in functioning of olfactory receptors
Ear Endolymph Transmission of auditory impulses
Skin Sweat Excretion of waste and regulation of temperature

Question 23.
Binocular vision gives us three dimensional vision. Then why do we close one eye when we aim at an object?
Answer:
Here distance is not important. Location of the object and eye must come in a straight line.

Question 24.
Ear canal → Cochlea → Tympanum → Auditory nerve
a. Correct the mistake, if any, in the above flowchart.
b. Modify the flow chart by adding the terms ‘oval window’ and ‘ear ossicles’
Answer:
a. Ear canal → Tympanum → Cochlea → Auditory nerve
b. Ear canal → Tympanum → Ear ossicles → Oval window → Cochlea →Auditory nerve

Question 25.
The flow chart related to the experience of smell is given below. Complete the flowchart.
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 9
Answer:
a.

  • A – Aromatic particles dissolve in the mucus inside the nostrils, stimulate olfactory receptors.
  • B – Generate impulses
  • C – Impulses reach cerebrum through olfactory nerve

Question 26.
The symptoms of two below. eye defects are given
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 10
Identify the defects. Write how these defects can be rectified.
Answer:
A – Glaucoma. Laser surgery
B – Cataract. Replace the lens with an artificial one.

Question 27.
Observe the picture and answer the questions given below.
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 11
a. Identify the photoreceptor.
b. Write the pigment and components of this pigment.
Answer:
a. Rod cell
b. Rhodopsin – opsin, retinal

Question 28.
The features of a fluid are given below.

  • Seen between retina and lens
  • Jelly like substance

a. Identify the fluid.
b. Write its function.
Answer:
a. Vitreous humour
b. Helps in maintaining the shape of the eye.

Question 29.
Given below are the two diseases of eyes.
i. Colour blindness
ii. Night blindness
a. Which of these is caused by malnutrition?
b. Deficiency of which nutrient causes this disease?
c. Write the main symptom of this disease.
Answer:
a. Night blindness
b. Vitamin A
c. Cannot see objects clearly in dim light.

Question 30.
Statements related to sense organs are given below:
Choose the correct ones.
a. Taste buds are the chemoreceptors seen in the papillae.
b. Receptors are uniformly distributed all over the skin.
c. Impulses from the olfactory receptors reach the cerebrum through the olfactory nerve.
d. We experience taste when impulses from the taste buds reach the cerebellum.
Answer:
a. Taste buds are the chemoreceptors seen in the papillae.
c. Impulses from the olfactory’ receptors reach the cerebrum through the olfactory nerve.

Question 31.
Light rays which reflect from the object are focussed on the retina and an image is formed,
a. Write the peculiarities of this image.
b. How do the. images formed in the two eyes combine? What is its advantage?
Answer:
a. Small, inverted, real.
b.

  • Three dimensional image of the object is formed due to the activity of the brain.
  • Binocular vision becomes possible.

Question 32.
Vision is enabled when the impulse from the retina reaches the cerebrum through the optic nerve.
a. Draw a flow chart showing the pathway of light from cornea to retina.
b. There is no vision at the point where the optic nerve starts. Why?
Answer:
a. Light → Cornea → Aqueous humour → Pupil → Lens Vitreous humour → Retina → Optic nerve
b. Rod cells and cone cells are absent in the part from where the optic nerve begins / Photoreceptors are absent.

Question 33.
Rhodopsin Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 12 Retinal + Opsin
a. How is this reaction related to vision?
b. How does the deficiency of vitamin A cause poor vision in dim light?
Answer:
a.

  • When light rays fall, rhodopsin dissociates into retinal and opsin.
  • Generates impulses.
  • When impulses reach the cerebrum, vision is experienced.

b

  • Amount of retinal decreases.
  • Causes a decrease in the level of rhodopsin.
  • Resynthesis of rhodopsin gets blocked.
  • Cannot see objects clearly in dim light / night blindness.

Question 34.
Observe the figure given below and answer the questions: .
Kerala SSLC Biology Chapter 2 Questions Windows of Knowledge 13
a. Which is the receptor seen in the figure?
b. In which sense organ is this receptor seen?
c. What is the function of this receptor?
Answer:
a. Olfactory receptor
b. Nose
c. Gets stimulated by aromatic particles and generates impulses.

Kerala SSLC Biology Chapter Wise Questions and Answers

Kerala SSLC Biology Chapter 8 Questions The Paths Traversed by Life

Kerala SSLC Biology Chapter 8 Questions The Paths Traversed by Life English Medium

Question 1.
The theory argues that life has originated in some other planet in the universe and accidentally reached the earth.
a. Natural selection
b. Chemical evolution
c. Panspermia
d. Mutation theory
Answer:
c. Panspermia

Question 2.
The chemical evolution theory was put forward by
a. Urey – Miller
b. Oparin – Halden
c. Watson – Crick
d. Hugo de Vries
Answer:
b. Oparin – Halden

Question 3.
The islands in which Charles Darwin conducted his study.
a. Galapagos
b. Indonesia
c. Japan
d. Sri Lanka
Answer:
a. Galapagos

Question 4.
Most primitive member of human race.
a. Ardipithecus ramidus
b. Homo habilis
c. Homo erectus
d. Homo sapiens
Answer: .
a. Ardipithecus ramidus

Question 5.
Fill up the blanks by observing the relationship – between the first pair.
a. Darwin: Natural selection
Hugo de Vries: ……………………….
b. Gibbon: Hominoidea
Gorilla: ……………………….
c. Contemporary to modern man: Homo neanderthalensis
Modern man:……………………….
Answer:
a. Mutation
b.Hominoidea
c. Homo sapiens

Question 6.
Find the odd one out, note down the common features of others.
a. Homo habilis, Orangutan, Homo sapiens, Ardipithecus ramidus
b. Gibbon, Monkey, Gorilla, Chimpanzee
c. Hydrogen, Nitrogen, Oxygen, Carbon dioxide
Answer:
a. Orangutan, others are members of human evolution.
b. Monkey, others are members of Hominoidea.
c. Oxygen, others are gases present on primitive earth.

Question 7.
The names of organisms that are included in the evolutionary history of modern man are given in the box. Select the answer from the box related to the statements given below.
Homo neanderthalensis, Homo erectus,
Ardipithecus ramidus, Homo sapiens,
Homo habilis

a. Modern man
b. Most primitive member of the human race.
c. Made weapons from stones and bone pieces.
d. Contemporary to modern man.
e. Have the ability to stand erect, thick chin and large teeth.
Answer:
a. Homo sapiens
b. Ardipithecus ramidus
c. Homo habilis
d. Homo neanderthalensis
e. Homo erectus

Question 8.
Some situations that helped in the origin of life existed in primitive earth. Select the situation from the following.
a. There was no water in primitive earth.
b. There was no free oxygen in primitive earth.
c. There were no gases in primitive earth.
d. There was availability of energy in primitive. earth.
Answer:
b. There was no free oxygen in primitive earth, d. There was availability of energy in primitive earth.

Question 9.
Read the description on bacteria and answer the questions given below.
Under favourable circumstances, bacteria divide every 20 minutes. The rapid multiplication results in the mutation in the DNA. Mutation causes the formation of new bacteria, producing different enzymes.
a. What will be the crisis created in the medical field by such changes in pathogenic bacteria?
b. Which theory of evolution is justified by changes in bacteria?
Answer:
a. Bacteria which show immunity to medicines are formed.
b. The theory of Natural Selection.

Question 10.
The main ideas related to an argument attempted to explain the history of evolution is given below.

  • The characters developed during the lifetime of organisms are called acquired characters.
  • The accumulation of acquired characters led to the formation of new species.

a. Name the scientist who put forward these ideas?
b. This argument was not accepted by the . scientific world. Why?
Answer:
a. Jean Baptist Lamarck.
b. The acquired characters were not inheritable.

Question 11.
Description of Darwin’s theory is given below. Which is the wrong statement?
a. Competition between organisms for the limited resources is known as struggle for existence.
b. Organisms with favourable variations survive.
c. The structure of organisms formed by continuous use is transmitted to next generations.
d. Organisms with unfavourable variations get eliminated.
Answer:
c. The structure of organisms formed by continuous use is transmitted to next generations.

Question 12.
What are the evidences given by biochemistry and physiology for evolution?
Answer:
Enzymes control chemical reactions in all organisms. Energy is stored in ATP molecules. Genes determine hereditary traits. Carbohydrates, proteins and fats are the basic substances. It is clear from these facts that different species that exist today have a common ancestor.

Question 13.
Arrange column B in accordance with column A.

A B
Ardipithecus ramidus Modern man.
Homo erectus Slender body.
Homo sapiens Most primitive member of the human race.
Have the ability to stand erect.

Answer:

A B
Ardipithecus ramidus Most primitive member of the human race.
Homo erectus Have the ability to stand erect.
Homo sapiens Modem man.

Question 14.
What are homologous organs? Write the evidences given by these for evolution?
Answer:
Organs that are similar in structure and perform different functions are called homologous organs. Such anatomical resemblances justify the inferences that all organisms evolved from a common ancestor.

Question 15.
Given below are the criticisms raised against – Darwin’s theory of Natural Selection.
a. Lack of experimental support.
b. Does not explain how variations within species are transmitted to the next generation.
What explanation will you give to this in the background of the advancement of genetics?
Answer:
a. Molecular biology, Mutation, etc.
b. Explanations from Neo Darwinism, Mutation, Crossing over.

Question 16.
Create an evolutionary tree of Anthropoidea by using the words given in the box.
Monkey, Gorilla, Gibbon, Cercopithecoidea, Orangutan, Man, Hominoidea, Chimpanzee.
Answer:
Kerala SSLC Biology Chapter 8 Questions The Paths Traversed by Life 1

Question 17.
Write two examples for the theories discussed among the scientists in connection with the origin of life.
Answer:
The theory of chemical evolution, The panspermia theory.

Question 18.
What are fossils? What are the inferences you can arrive at from fossil studies?
Answer:

  • Fossils are the remnants of primitive organisms. The inferences that we can arrive at from such studies.
  • Primitive fossils have simple structure.
  • Recently formed fossils have complex structure.
  • Certain fossils are connecting links between different species.

Question 19.
Gibbon, Baboons, Oranguttan, Gorilla. Find the odd one. In which group the other organisms belong? Write the characteristics of this group.
Answer:
Baboons Gibbon, Oranguttan, Gorilla belong to the Hominoidea group.
The characteristics of Hominoidea are developed brain, freely movable hands.

Question 20.
Dinesh applied DDT, a pesticide in his garden to control termites. He could control termites successfully during the initial stages, but subsequent usage of the same did not produce any results. Evaluate the survival of termites on the basis of Natural Selection.
Answer:
According to The Theory of natural selection, the organisms are in competition for limited resources (struggle for existence). Only organisms with favourable variations survive. And this leads to the evolution of new species with favourable variations. They become accustomed to the new environment.

This new species produce more number of offsprings (overproduction).
Here the pests have variations to overcome the DDT. Organisms with favourable variations survive and lead to the evolution of new species which can survive DDT.

Question 21.
Write your inference by analyzing the following information in connection with evolution.
Difference from the amino acids in the beta chain of haemoglobin in man.
Chimpanzee: Nil
Gorilla: difference of one amino acid Rat: difference of 31 amino acids
a. Substantiate the reason for variations of amino acids of protein like haemoglobin in above organisms.
b. Write the advantage of the micro-level knowledge of protein and genes of related organism.
Answer:
a. Mutation
b. Through a comparative study of protein molecules in different species, the evolutionary relationship among organisms can be identified.
This is an effective method to draw the evolution showing the branching of organisms from a common ancestor.

22. Tabulate the data appropriately in the box given below:
i. Chemical evolution
ii. Natural selection
iii. Panspermia theory
iv. Mutation theory

Origin of Life Evolution
………………………….

………………………….

…………………………

………………………….

 

Answer:

Origin of Life Evolution
Chemical evolution Natural selection
Panspermia theory Mutation theory

Question 23.
“The coñstant use of antibiotics develops resistance in bacteria” Substantiate the above statement on the basis of the theory of natural selection.
Answer:

  • Presence of antibiotics in body.
  • Bacteria capable of and incapable of resisting antibiotics
  • Those that are capable of resisting antibiotics will exist.
  • Resistant bacteria produce more offspring.

Question 24.
Scientific study of the remnants, body parts. and imprints of primitive organisms are evidences on evolution.
a. What inferences do we arrive at, through such scientific studies?
b. How will you explain these inferences as evidences on evolution?
Answer:
a.

  • Primitive fossils have simple structure.
  • Recently formed fossils have complex structure.
  • Certain fossils are connecting links between different species.

b.

  • Organisms with complex structure are formed from those with simple structure.
  • Certain fossils indicate the evolution of one species from another species.

Question 25.
A few concepts of scientists like Darwin and Malthus are given below. Classify them in the table given below.
a. Selection by nature leads to the diversity of species.
b. Rate of food production does not increase proportionately to the increase in population.
c. Those organisms that ovèrcome the unfavourable situations will survive.
d. Scarcity of food and starvation lead to struggle for existence.

Concepts of Darwin Concepts of Matthus
……………………………

……………………………

……………………………

……………………………

Answer:
Concepts of Darwin
a. Selection by nature leads to the diversity of species.
c. Those organisms that overcome the unfavourable situations will survive.

Concepts of Matthus
b. Rate of food production does not increase proportionately to the increase in population.
d. Scarcity of food and starvation lead to struggle for existence.

Question 26.
An excerpt from the science article ‘Man and Evolution’ is given below. Analyse the excerpt and answer the questions.
Certain evolutionary features that make man different from other animals are included in evolutionary history. This helped him in his dominance over nature and other organisms. His interferences had created a negative impact on the existence of other organisms.

a. What are the features that make man different from other animals?
b. Has man’s interference led to Biodiversity deterioration as mentioned in the excerpt? Evaluate.

Answer:
a. High cranial capacity, ability to stand erect, ability to walk on two legs, ability to make and use machines and tools, cultural development.
b. Yes. Climate changes, deteriorating habitats, extinction.

Kerala SSLC Biology Chapter Wise Questions and Answers

Kerala SSLC Biology Chapter 7 Questions Genetics for the Future

Kerala SSLC Biology Chapter 7 Questions Genetics for the Future English Medium

Question 1.
DNA fingerprinting was discovered by
a. Watson
b. Crick
c. Mendel
d. Alec Jeffrey
Answer:
d. Alec Jeffrey

Question 2.
Fill up the blanks by observing the relationship between the first pair
Molecular scissors: Restriction endonuclease
Molecular glue: ……………………….
Answer:
Ligase

Question 3.
What is the significance of human genome project?
Answer:
Even though science has progressed a lot, we couldn’t control genetic diseases. The reason for this is that we could not identify the exact gene and its location which is responsible for each trait. In 1990, the Human Genome Project was started as an attempt to solve the issue.

As a result of experiments conducted in various laboratories of the world until 2003, the secrets of human genome were revealed. With this we can identify the location of a gene in the DNA, responsible for a particular trait.

Question 4.
The stages in the production of bacteria liar are capable of producing insulin through genetic engineering is given below. Arrange them in correct order
a. Cuttiiig the plasmid of bacteria.
b. Inserting DNA in the bacterial cell.
c. Bacteria produce in active form of insulin.
d. Cutting the gene responsible for the production of insulin from human DNA.
e. Producing active insulin.
f. Providing a favourable medium for the multiplication of bacteria.
g. Joining the gene responsible for the production of insulin from human DNA to the plasmid of bacteria.
Answer:
d, a, g, b, f, e, e

Question 5.
Genetic engineering a threat to mankind. Write your opinion about this statement.
Answer:
It is criticized that genetically modified varieties cause harm to indigenous varieties and may cause health issues to humans. Application of genetically modified pathogens and pathogens multiplied ” through biotechnology upon enemies is called Bioware. This becomes a threat to the existence of human beings.

Question 6.
Bacteria is not used as a pharm animal. Write your opinion.
Answer:
Genes responsible for the production of human insulin, growth hormones, etc., are identified and inserted in animals like cow, pig, etc., transforming them into pharm animals. Bacteria were used for such experiments in the beginning. However, the culturing of bacteria is not so easy. They should be cultured with utmost care in the laboratory, It is easy to rear animals.

Question 7.
“Genetic engineering is the branch of science that transforms the living world’’.
a. What is your opinion on the above statement?
b. Give reason to substantiate your opinion.
Answer:
a. I agree with this statement. Genetic engineering is the technology of controlling traits of organisms by bringing about desirable changes in the genetic constitution of organisms.

b. Medicine – Plants and animals that produce medicines
Gene therapy – Remedy for genetic diseases
DNA fingerprinting – Forensic test

Question 8.
Arrange the statements suitably in the table given below.
a. The enzyme used to cut genes
b. Ligase
c. The enzyme used for joining genes
d. Restriction endonuclease
Answer:

Genetic scissors Genetic glue
……………………..
……………………..
……………………..
……………………..
Genetic scissors Genetic glue
The enzyme used to cut genes Ligase
Restriction endonuclease The enzyme used for joining genes

Question 9.
The stages in the production of insulin from bacteria are given below. Complete the missing stages.
Kerala SSLC Biology Chapter 7 Questions Genetics for the Future 2

Answer:
a. Cutting bacterial DNA (plasmid).
b. Then insert this DNA in the bacterial cell.
c. Bacteria produce inactive form of insulin.

Question 10.
Observe the news and answer the question given below.
DNA fingerprinting helped to identify real culprit.
Kochi: Culprit can be identified through DNA testing.
a. What is the basis of DNA testing?
b. How can culprits be identified through DNA testing.
Answer:
a. The arrangement of nucleotides in the DNA of each person differs. This finding leads to the DNA testing.

b. DNA of the skin, hair, nail, blood and other body fluids obtained from the place of murder, robbery etc. is compared with the DNA of suspected persons. Thus the real culprit can be identified from among the suspected persons through this method.

Question 11.
Ligase is referred as molecular glue and restriction endonuclease as molecular scissors. If these are utilized, great many achievements can be produced in the fields of agriculture and medicine.
a. What is the technology mentioned above?
b. What is the use of ligase and restriction endonuclease in this technology?
Answer:
a. Genetic engineering
b. Ligase – used for joining genes Restriction endonuclease – used for cutting of genes

Question 12.
Observe the logo given below.
Kerala SSLC Biology Chapter 7 Questions Genetics for the Future 1
a. What does it indicate?
b. What are the findings of this project?
Answer:
a. Human Genome Project.
b. Human genome has about 24000 functional genes.

  • Major share of human DNA includes junk genes.
  • There is only 0.2 percent difference in DNA among humans.
  • About 200 genes in human genome are identical to those in bacteria.

Question 13.
Given below is a word tree prepared by Appu for classroom presentation. Help him to complete the tree by choosing the words given in the box:
Junk genes, Ligase, Gene therapy, DNA profiling, Restriction endonuclease, Gene mapping, Plasmid, Genetic engineering
Kerala SSLC Biology Chapter 7 Questions Genetics for the Future 2
Answer:
a. Restriction endonuclease
b. Ligase
c. DNA profiling
d. Junk genes
e. Gene mapping
f. Gene therapy

Question 14.
Observe the table and form matching pairs.

a. DNA profiling i. Treatment for genetic diseases.
b. Gene mapping ii. Testing the arrangement of nucleotides.
c. Gene therapy iii. The sum of genetic material present in an organism
d. Genome iv. Locating the position of a gene in the DNA.

Answer:

a. DNA profiling i. Testing the arrangement of nucleotides.
b. Gene mapping ii. Locating the position of a gene in the DNA.
c. Gene therapy iii. Treatment for genetic diseases.
d. Genome iv. The sum of genetic material present in an organism.

Question 15.
Complete the table.

Protein required for treatment Disease/Symptom
………………a……………… Viral diseases
Insulin ………………b………………
………………c……………… Pain
Somatotropin ………………d………………

Answer:

Protein required for treatment Disease/Symptom
Interferons Viral diseases
Insulin Diabetes
Endorphin Pain
Somatotropin Growth disorders

Kerala SSLC Biology Chapter Wise Questions and Answers

Kerala Syllabus Class 10 Biology Solutions Chapter 5 Soldiers of Defense

Kerala Syllabus 10th Standard Biology Guide Chapter 5 Soldiers of Defense

Question 1.
What are the uses of wearing masks in situations where epidemics spread out?
Answer:

  • Prevent the entry of germs.
  • Prevent the entry of pathogens from one person to another.

Question 2.
What do you mean by the term defence?
Answer:
Defence is the ability of the body to prevent the entry of pathogens and to destroy those that have already entered the body.

Question 3.
What are the defense mechanisms of the body?
Answer:
Body coverings like skin, mucous membrane and body secretions like mucous, saliva and tear are the defence mechanisms of the body. Body fluids like blood and lymph also play an important role in defence mechanism.

Question 4.
What is the role of skin in defense?
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 5 Soldiers of Defense 1
A protein called keratin present in the epidermis prevents the entry of germs. Sebum produced by the sebaceous gland makes the skin oily and waterproof. The disinfectants present in the sweat produced by sweat gland destroy the germs.

Question 5.
What is mucous membrane?
Answer:
The mucous membrane is protective covering of body parts.
Kerala Syllabus Class 10 Biology Solutions Chapter 5 Soldiers of Defense 2

Question 6.
What is the function of mucous membrane?
Answer:
Pathogens trapped in the mucus produced by mucous membrane, get destroyed. The destroyed germs are expelled out by the cilia cells of the mucous membrane.

Question 7.
What is the role of useful bacteria seen in skin and mucous membrane?
Answer:
Coverings of the body act as a habitat for many useful bacteria. The germs that enter the body need to compete with such useful bacteria for shelter and nutrients. A great number of germs get destroyed in this competition.

Question 8.
How the body secretions help to defend pathogens?
Answer:

  • The disinfectants present in the sweat produced by this gland destroy the germs.
  • Pathogens trapped in the mucus produced by this membrane, get destroyed. The destroyed germs are expelled out by the cilia cells of the mucous membrane.
  • The wax in the ear prevents pathogens.
  • The enzyme lysozyme present in tear and saliva fights against germs.
  • The hydrochloric acid present in the stomach has the ability to destroy germs. It kills the germs that reach the stomach along with food.
  • Lysozyme present in the urine kills the germs.

Question 9.
What are the defense strategies of body fluids?
Answer:
Body fluids like blood and lymph play an important role in defense mechanism. These body fluids follow different defense strategies like controlling the entry of germs into the body, neutralising germs and the toxic substances they produce, preventing their multiplication, etc.

Question 10.
What are the defense action of white blood cells?
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 5 Soldiers of Defense 4

  • Neutrophil – Engulfs bacteria, synthesizes chemicals that destroys bacteria.
  • Basophil – Stimulates other white blood cells. Dilates the blood vessels.
  • Eosinophil – Synthesizes chemicals that destroy foreign bodies. Synthesizes chemicals required for
    the inflammatory responses.
  • Monocyte – Engulfs and destroys germs.
  • Lymphocyte-Identifies and destroys germs specifically.

Question 11.
Explain inflammatory response.
Answer:
The cells that get damaged by a wound or an infection produce certain chemical substances. These substances dilate the blood vessels thereby increasing the blood flow. Blood plasma and white blood cells reach the wound site. This is the reason for the swelling of the wound site. This defense mechanism is known as inflammatory response.
Kerala Syllabus Class 10 Biology Solutions Chapter 5 Soldiers of Defense 5

Question 12.
What is the advantage of the dilation of blood vessels at the wound site?
Answer:
The cells that get damaged by a wound or an infection produce certain chemical substances. These substances dilate the blood vessels thereby increasing the blood flow. Blood plasma and white blood cells reach the wound site. The white blood cells destroy germs.

Question 13.
What is the role of white blood cells in the inflammatory response?
Answer:
White blood cells reach the wound site through the walls of the capillaries. Neutrophils and monocytes engulf and destroy germs.

Question 14.
Is inflammatory response a defense activity? Why?
Answer:
Yes. Inflammatory response is a defense activity. It is the mechanism that destroys the germs that have entered the body. This is a second-level defense mechanism.

Question 15.
Prepare a flowchart showing the stages of inflammatory response.
Answer:
Germs enter through wounds → Produces chemical messages → Blood vessels dilate → White blood cells reach the wound site through the walls of the capillaries → Neutrophils and monocytes engulf and destroy germs.

Question 16.
What is phagocytosis?
Answer:
Phagocytosis is the process of engulfing and destroying germs. The cells engaged in this process are called phagocytes. Monocytes and neutrophils are phagocytes.

Question 17.
Prepare a flowchart show the stages in phagocýiosis.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 5 Soldiers of Defense 6
Phagocytes reach near the pathogen → Engulfs pathogen in the membrane sac → Lysosome combines with membrane sac → The pathogens are degenerated and destroyed by the enzymes in lysosome.

Question 18.
Prepare a note on blood clotting.
Answer:
Blood clotting is a defense mechanism to prevent the loss of blood through wounds. Wounds cause loss of blood. Tissues degenerate to form the enzyme called thromboplastin. Thromboplastin converts prothrombin in the plasma to thrombin in the presence of calcium ions and vitamin K. Thrombin converts the fibrinogen in the plasma to fibrin. Blood clot is formed by the entangling of platelets and red blood cells in the fibrin network.

Question 19.
Explain the situation in which wound scar remains.
Answer:
Healing of the wound is a stage after inflammatory response and blood clotting. When wound occurs, new tissues are formed in the place of the tissues damaged by the wound.

In such situations, the wound scar does not remain. In cases when new tissues cannot be formed, the connective tissue heals the wound. In such situations, the wound scar Remains.

Question 20.
Fever is a defense mechanism. Why?
Answer:
Pathogens enter the body. Then the presence of toxins produced by the pathogens stimulates the white blood cells. The chemical substances produced by the white blood cells raise the body temperature. The rise in body temperature reduces the rate of multiplication of pathogens and increases the effect of phagocytosis. So fever is a defense mechanism.

Question 21.
If the rise in body temperature persists for a long time, it is necessary to seek medical assistance immediately. Why?
Answer:
When infection becomes uncontrollable, the body temperature may rise very high. We take medicines to reduce the body temperature. But it is advisable to treat after diagnosing the exact reason. If the rise in body temperature persists for a long time, it may badly affect the internal organs including the brain. Hence it is necessary to seek medical assistance immediately.

Question 22.
Define non – specific defense.
Answer:
Non-specific defense mechanism is a mechanism that protects us from all pathogens without considering their characteristic features.

Question 23.
Define specific defense.
Answer:
Foreign bodies or pathogens that enter the body and stimulate the defense mechanism are called antigens. The defense mechanism that identifies the structure of each antigen and destroys it specifically is called specific defense.

Question 24.
Prepare a short note on lymphocytes.
Answer:
In certain situations, pathogens enter the body and multiply by overcoming the immune system. Specific defense is the system which identifies and destroys such pathogens. White blood cells known as lymphocytes are capable of destroying the pathogens in this way. Lymphocytes are of two types, namely B lymphocytes and T lymphocytes. B lymphocytes mature in the bone marrow. T lymphocytes mature in the thymus.

Question 25.
How do B lymphocytes act?
Answer:
Foreign bodies or pathogens that enter the body and stimulate the defense mechanism are called antigens. B- Lymphocytes produce certain proteins that act against antigens. These are called antibodies.
Antibodies destroy the pathogens in three different ways.

  1. Destroy the bacteria by disintegrating their cell membrane.
  2. Neutralise the toxin of the antigens.
  3. Destroy the pathogens by stimulating other white blood cells.

Question 26.
How do T lymphocytes act?
Answer:
T lymphocytes stimulate other defense cells of the body. Moreover, these cells are capable of destroying cancer cells and cells affected by virus.

Question 27.
Why is the defense mechanism of lymphocytes known as specific defense mechanism?
Answer:
Lymphocytes become activated in the presence of j certain particular types of antigens. Lymphocytes can defend only such antigens. Hence, this; defense mechanism is known as specific defense mechanism.

Question 28.
What are the defense mechanisms of blood?
Answer:
Raising body temperature, production of antibodies, healing of wound, blood clotting, inflammatory response, phagocytosis.

Question 29.
How does lymph help in defense mechanisms? j
Answer:
The lymph, formed from the blood and reabsorbed into blood has a prominent role in defense j mechanisms, like the blood itself. Lymph contains plenty of lymphocytes. They destroy the disease causing bacteria in lymph nodes and spleen.

Question 30.
What is immunization?
Answer:
Defense mechanisms become slow when germs enter the body. This causes the spread and multiplication of germs. Immunization is the artificial method to make the defense cells alert against the attack of pathogens.

Question 31.
What are vaccines? What are the component of vaccines?
Answer:
Vaccines are the substances used for artificial immunization. Any one of the components from alive or dead neutralised germs, neutralised toxins or cellular parts of the pathogens will be the component of each vaccine.

Question 32.
What is the role of Edward Jermer in immunization?
Answer:
Edward Jenner, an English doctor started immunization. He observed that people affected by cowpox escaped from the attack of smallpox. He injected the pus taken from a cowpox patient into the body of an 8-year-old boy. The boy was affected by cowpox and recovered.

After two months the pus taken from a smallpox patient was injected into the boy. He was not affected by smallpox. The immunization programmes got the name vaccination from the Latin word ‘vacca’ meaning cOw, in memory of the cowpox experiments of Jenner.

Question 33.
How vaccines help in immunization?
Answer:
Vaccines are the substances used for artificial immunization. These act as antigens that stimulate the defense mechanism of the body. Antibodies are formed in the body against them. These antibodies are retained in the body which in future protect the body from the pathogen responsible for the same disease.

Question 34.
Prepare a table related to vaccines and diseases.
Answer:

Vaccine Disease
B.C.G. Tuberculosis
O.P.V. Polio
Pentavalent Diphtheria, tetanus, pertussis (whooping cough), hepatitis B and Haemophilus influenza type b
M.M.R. Measles, mumps, and rubella (German measles)
T.T Tetanus

Question 35.
Prepare a note on the various systems of medicine.
Answer:
Medical treatment becomes necessary when we are affected by diseases, crossing all obstacles of our immune system. We depend on the various systems of medicine to recover from diseases.

In various parts of the world, methods of treatment have evolved in accordance with the lifestyle of the people, their culture and available natural resources. These methods are the result of long periods of experience and observation.

Ayurveda: It is a system of treatment which prevailed in India from the ancient times. Beyond being an urgent treatment measure against some diseases, Ayurveda gains acceptance as a lifestyle to maintain the body fit. The speciality of Ayurveda is the medicine, taken from nature.

Homoeopathy: The main principle behind homoeopathy is that the causative factor of the disease can itself effect the cure. This is a system of treatment introduced by Samuel Haniman, a German doctor. Homoeopathy gives great importance to the symptoms in each individual since it aims at treating not the disease but the patient. Another significant principle of this system of treatment is that the more the medicine is diluted the more is its potency.
Unani: The treatment in Unani is based on some principles put forward by Hippocrates. The diagnosis of a disease is done by checking pulse.

Allopathy: This is a cosmopolitan medical practice widely used all over the world. This branch of medicine, introduced by the ancient Greek physician Hippocrates, gives much importance to diagnosis, treatment, medicines, etc.

Question 36. Prepare a table containing the equipment for diagnosis and their use.
Answer:

Equipment for diagnosis Uses
Stethoscope Measuring heartbeat
Sphygmomanometer Measuring blood pressure
Electroencephalogram (EEG) To record electric waves in the brain
Electrocardiogram (ECG) To record electric waves in the heart muscle
Ultrasound Scanner To understand the structure of internal organs using ultrasonic sound waves.
C.T. Scanner(Computed Tomography Scanner) To get three-dimensional visuals of internal organs with the help of computer, using X-rays
MRI Scanner (Magnetic Resonance Imaging Scanner) To get three-dimensional visuals of internal organs.

Question 37.
What are the different factors in blood?
Answer:

Blood factor Normal Value
Haemoglobin 12-17 gm/100 ml of blood
Number of White Blood Cells 5000- 10000/ml of blood
Number of Red Blood Cells 45 lakhs to 60 lakhs/ml of blood
Number of platelets 2.5 lakhs to 3.5 lakhs/ml of blood

Question 38.
Prepare a lubie containing the specializations in medicine ami the related areas.
Answer:

Specialization Related Area
Cardiology Treatment of heart
Ophthalmology Treatment of eye
Neurology Treatment of disorders of the nervous system.
Chemotherapy Cancer treatment
E.N.T Treatment of ear, nose, and throat disorders.

Question 39.
What are antibiotics?
Answer:
Medicines that are extracted from microorganisms like bacteria, fungi. etc. and used to destroy bacteria are called antibiotics. They can be used externally and internally.

Question 40.
Explain the role of Alexander Fleming in the discovery of antibiotics.
Answer:
It was Alexander Fleming who first discovered antibiotics in 1928. He accidentally discovered that the fungus Penicillium notatum has the ability to destroy bacteria. But it took several years to extract medicine from it.

Question 41.
What are the side effects caused by the regular use of antibiotics?
Answer:
Antibiotics are used to resist bacterial diseases. Though antibiotics are effective medicines, their regular use brings many side effects.
Some important side effects of regular use are it develops immunity in pathogens against antibiotics, destroys useful bacteria in the body,
reduces the quantity of sorne vitamins in the body.

Question 42.
Observe figures A, B and C and identify the instances in which the following type of first aid is given.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 5 Soldiers of Defense 7
A – Giving artificial respiration – Artificial respiration, breathing induced by some manipulative technique when natural respiration has ceased or is faltering. Such techniques, if applied quickly and properly. can prevent some deaths from drowning, choking, strangulation, suffocation, carbon monoxide poisoning, and electric shock.

B – Arm supported by sling – During bone fracture
C – Removing objects stuck in trachea – Block in trachea

Question 43.
What is blood transfusion?
Answer:
The transfer of blood from one person to another is called blood transfusion.

Question 44.
What all things should be taken care of while transfusing blood?
Answer:

  • People in the age group 18-60 can donate blood.
  • Blood donation can be done once in three months.
  • Blood donation causes no problem to the donor’s health.
  • Pregnant women and breastfeeding mothers should not donate blood.
  • Persons with communicable diseases
    (transmitted through blood) should not donate blood.

Question 45.
What are the different types öf blood groups?
Answer:
A, B, AB, O

Question 46.
What is the basis of blood grouping?
Answer:
The basis of blood grouping is the presence of antigen A and antigen Binredbloodcells. The blood group of a person is named according to the antigen present in that person’s blood.

Question 47.
Write the importance of antibody in blood groups.
Answer:
In blood transfusion, antibodies present in the blood plasma are of special importance. In blood group A, antibody b and in group B, antibody a are present.

Question 48.
What is antigen D?
Answer:
In addition to antigens A and B, another antigen called D or Rh factor is present in the cell membrane of red blood cells of certain persons.
The blood groups in hich Rh factor is present are known as positive blood groups and those without Rh factor are called negative blood groups.

Question 49.
What is the importance of blood group in blood transfusion?
Answer:
When a foreign antigen reaches one’s blood, it stimulates the defense mechanism. On receiving unmatching blood, the antigen present in the donor’s blood and the antibody present in the recipientes blood will react with each other and form a blood clot. Hence, everyone cannot receive blood from all blood groups.

For example, in blood group A, antigen A and in group B, antigen B are present. If a person with blood group A receives blood from a person with B group blood, the recipient’s blood does not contain B antigen. So it stimulates defense activity of the body. As a result, antigen B in blood group B forms a clot with antibody of A group blood.

Question 50.
What are the structural methods in the defense of plants?
Answer:
The characteristics in their body structure and the specific molecules produced by plant tissues protect the plants from diseases. Wax covering, cuticle, bark of plant and cell wall are the structural methods in the defense of plants. Waxy covering and cuticle prevent the entry of germs through leaves. The bark of plants protects inner cells from the direct contact of pathogens. Cell wall is a well equipped resistant coat.

Question 51.
What are the biochemical methods in the defense of plants?
Answer:
Chemical substances such as lignin, cutin, suberin, etc., provide rigidity to the cell wall. A polysaccharide called callose prevents the entry
of germs which have crossed the cell wall, through the cell membrane.

Let Us Assess

Question 1.
Which among the following is not included in non-specific body defense?
a. production of sebum.
b.action of hydrochloric acid in the stomach.
c. action of B lymphocytes.
d. action of lysozyme in saliva.
Answer:
c. action of B lymphocytes.

Question 2.
Write the functions of blood cells in the defense mechanism of the body.
Answer:
Neutrophil – Engulfs bacteria, synthesizes chemicals that destroys bacteria.
Basophil – Stimulates other white blood cells. Dilates the blood vessels.
Eosinophil – Synthesizes chemicals that destroy foreign bodies. Synthesizes chemicals required for the inflammatory responses.
Monocyte – Engulfs and destroys germs.
Lymphocyte – Identifies and destroys germs specifically.

Question 3.
What is the basis of grouping blood into different types? Everybody cannot receive blood of all blood groups. Why?
Answer:
The basis of blood grouping is the presence of antigen A and antigen B in red blood cells. The blood group of a person is named according to the antigen present in that person’s blood. In blood transfusion, antibodies present in the blood plasma are of special importance. In blood group A, antibody ‘b’ and in group B, antibody ‘a’ are present.

When a foreign antigen reaches one’s blood, it stimulates the defense mechanism. On receiving unmatching blood, the antigen present in the donor’s blood and the antibody present in the recipient’s blood will react with each other and form a blood clot.

Hence, everyone cannot receive blood from all blood groups. For example, in blood group A, antigen A and in group B, antigen B are present. If a person with blood group A receives blood from a person with B group blood, the recipient’s blood does not contain B antigen. So it stimulates defense activity of the body. As a result, antigen B in blood group B forms a clot with antibody ‘a’ of A group blood.

Kerala Syllabus 10th Standard Biology Guide

Kerala Syllabus Class 10 Biology Solutions Chapter 4 Keeping Diseases Away

Kerala Syllabus 10th Standard Biology Guide Chapter 4 Keeping Diseases Away

Question 1.
What threatended the state again, soon after the great floods?
Answer:
The spread of contagious diseases threatended the state soon after the flood. Increase in number of rats may lead to spreading of rat fever. There is a shortage of drinking water in the flood affected areas of the state. The mental health of children in flood affected areas also is in threat.

Question 2.
What are the reasons for the proliferation of diseases?
Answer:
Lack of hygiene, Dirty surroundings, Environmental pollution, Stagnant water, Organic wastes, Poor sanitation, etc. lead to the proliferation of diseases.

Question 3.
What are the pathogenic microorganisms.?
Answer:
Bacteria, Fungus, Virus, Protozoa

Question 4.
How are pathogens transmitted from one person to another?
Answer:
Pathogens are transmitted from one person to another by contact, through contaminated food and water, cough, sneezing, unsterilized equipments, vectors and cloth.

Question 5.
What can we do to avoid the proliferation of diseases?
Answer:

Situations Practical suggestions
Lack of hygiene Awareness about hygiene
Dirty surroundings Continuous cleaning activities
Environmental pollution Continuous cleaning activities
Stagnant water Provide situations for flowing of water
Organic wastes Organic waste disposal
Poor sanitation Common urinal and toilets

Question 6.
Prepare a short note on bacteria.
Answer:
Bacteria is a prokaryote. They enter the body and multiply through binary fission. The toxins produced by them destroy cells and cause disease.

Question 7.
Prepare a short note on rat fever.
Answer:
Leptospira is the bacteria that causes rat fever. The bacteria that comes out through the urine of rat, dog and certain other animals remain alive in stagnant water and moisture. When bacteria reach blood through wounds, they affect body cells and produce certain toxins.

They cause damage to blood capillaries which in turn leads to internal bleeding. Severe fever, headache, muscle pain, redness in eyes, etc. are the major symptoms. Rat fever can be completely cured through early diagnosis and treatment. The realization that immunization is better than treatment is very important to stop the spread of disease.

Question 8.
What are the precautions taken after flood?
Answer:
The Department of Health has given numerous instructions to avoid health issues that may arise after overcoming the emergency situations. Drinking boiled water and water purified using enough quantity of chlorine prevents water borne diseases. As there is a chance for the multiplication of mosquitoes in stagnant water, proper measures to check increase in mosquitoes should be adopted.

For controlling diseases like rat fever, eliminate the vectors and take preventive medicines as per the directions of experts. Disease affected persons must undergo diagnostic tests to confirm their illness and should take proper medicines. People living in unsafe places must shift to safe places as per instructions. Ensure personal hygiene and environmental hygiene at the rehabilitation centres and create an atmosphere to protect health.

Question 9.
Name the pathogen of Diphtheria.
Answer:
Diphtheria spreads through cough, sneezing or directly from the infected person to another person. Diphtheria affects the mucus membrane of the nose and the throat. Corynebacterium diphtheriae is the pathogen.

Question 10.
What are the symptoms of Diphtheria?
Answer:
Diphtheria affects the mucus membrane of the nose and the throat. Toxins produced by the Corynebacterium diphtheriae cause fever, throat pain and inflammation in the lymph glands of the throat. Cells in the mucus membrane which are destroyed by the toxins produce an ash coloured thick coating in the throat within two or three days. Gradually brain, heart and kidneys are affected.

Question 11.
Explain the treatment of Diphtheria.
Answer:
Antitoxins which act against the toxins are used to protect the uninfected cells. But, if the disease becomes severe the patient cannot be recovered through medication. So vaccination is the best preventive method.

Question 12.
Which is the causative agent of tuberculosis?
Answer:
Tuberculosis is an air borne disease that affects the lungs. Tuberculosis is caused by the bacterium Mycobacterium tuberculosis.

Question 13.
Which are the symptoms of tuberculosis?
Answer:
This disease can affect us at any age. Loss of body weight, fatigue and persistent cough are the major symptoms.

Question 14.
How does tuberculosis spread?
Answer:
When the patient speaks, coughs or sneezes, the pathogens spread to air providing a chance to reach other people.

Question 15.
Which parts of the body can be affected by tuberculosis?
Answer:
Tuberculosis mainly affects the lungs-. Kidneys, bones, joints, brain, etc., are also affected by this disease.

Question 16.
Name the vaccine against tuberculosis.
Answer:
BCG is used as preventive vaccine against tuberculosis

Question 17.
Prepare a short note on virus.
Answer:
Virus has the simple structure with a DNA or RNA molecule within a protein coat. Virus has no cell organelles as seen in normal cells. Hence virus multiplies by taking control over the genetic mechanism of the host cells. Viruses infect not only human beings but also plants, other animals and even bacteria.

Question 18.
Which is the natural vector of Nipah virus?
Answer:
Fruit eating bats act as the Nipah virus vectors.

Question 19.
What are the situations that enable the Nipah virus to enter humans?
Answer:
Fruit eating bats act as the Nipah virus vectors. ’ From the saliva and urine of fruit eating bats that are seen in the remains of fruits eaten by bats, Nipah virus enters humans and pigs. From pigs also Nipah virus enters humans.

Question 20.
Explain AIDS.
Answer:
AIDS (Acquired Immuno Deficiency Syndrome) is a dreadful disease that has gripped the world by fear. Lymphocytes play a major role in providing immunity to the body. HIV (Human Immuno¬deficiency Virus) enters the body and multiplies using the genetic mechanism of lymphocytes. Hence the number of lymphocytes decreases considerably and reduces the immunity of the body. Various other pathogens which enter the body in such a situation make the condition of AIDS even more fatal.

Question 21.
What are the ways by which HIV spreads?
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 4 Keeping Diseases Away 1

Question 22.
How AIDS does not spread?
Answer:

  • By touch, shaking hands, coughing, sneezing, etc.
  • Through insects like mosquitoes, houseflies, etc.
  • By staying together and sharing food
  • By using same toilets
  • By taking bath in the same pond.

Question 23.
What is the reason for hepatitis?
Answer:
Hepatitis is a liver disease. Hepatitis is also caused by virus.

Question 24.
What are the symptoms of hepatitis?
Answer:
Inflammation of the liver is its major symptom. When the flow of bile secreted by the liver is blocked, an increase in the level of bile pigment called bilirubin in blood is noticed. This imparts dark yellow colour to the mucus membrane, white portion of the eyes and the nails. This is the external symptom of the disease.

Question 25.
How hepatitis get transmitted?
Answer:
Disease gets transmitted through contaminated food and water, blood components and excreta of the patient. Certain hepatitis do get transmitted in the same way as the transmission of HTV.

Question 26.
What are the preventive measures taken against the transmission of dengue fever and chikungunya?
Answer:
Dengue fever and Chikungunya that are common in Kerala are also viral diseases. These diseases are transmitted through mosquitoes. Contaminated surroundings promote the multiplication of pathogens. The increase in the number of vectors like mosquitoes leads to the spread of communicable diseases much beyond control. Observing dry day, prevent the stagnation of water, etc. can be taken to prevent the multiplication of mosquitoes. It is our duty to keep our surroundings clean.

Question 27.
Explain about fungus.
Answer:
Fungi are of various types. Some fungi are pathogenic. The toxins produced by the fungi cause diseases.

Question 28.
Prepare a table containing diseases caused by fungus, symptoms and mode of transmission.
Answer:

Diseases caused by fungus Mode of transmission Symptoms
Ringworm Spreads through contact. Manifests as round, red blisters on the skin
Athletes’ foot Pathogens enter through the toes when they come in contact with contaminated water, and soil. Manifests on the sole of the foot and between the toes. Appearance of reddish scaly rashes that cause itching

Question 29.
Write about malaria.
Answer:
Malaria is caused by the protozoan, plasmodium. High fever with shivering and profuse sweating are the major symptoms of malaria. Other symptoms include headache, vomiting, diarrhoea, anaemia. The vector is female Anopheles mosquito.

Question 30.
Write about diseases in which worms as pathogens.
Answer:
Filariasis is caused by filarial worms that are spread by culex mosquitoes. The worms stay in the lymph ducts and obstruct the flow of lymph by blocking the ducts. This causes swelling in the lymph ducts in the legs.

Question 31.
What are the preventive measures to be taken against communicable diseases?
Answer:
Contaminated surroundings promote the multiplication of pathogen’s. The increase in the number of vectors like mosquitoes leads to the spread of communicable diseases much beyond control. In order to control the spread of communicable diseases, it is necessary to avoid situations that lead to the multiplication of pathogens and vectors. It is our duty to keep our surroundings clean.

Question 32.
What are non-pathogenic diseases?
Answer:

  • Deficiency of nutrients – Marasmus, Kwashiorkor, Rickets
  • Lifestyle diseases – Diabetes, Heart attack, Hypertension
  • Occupational diseases – Silicosis, Asbestosis
  • Genetic diseases – Haemophilia, Sickle cell anaemia.

Question 33.
Why do haemophilia patients lose blood excessively, even through minor wounds?
Answer:
Blood clots with the help of some proteins present in blood plasma. The synthesis of proteins fails when the genes that control protein synthesis become defective. Hence excess blood is lost even through minor wounds.

Question 34.
What is the treatment of haemophilia?
Answer:
As haemophilia is a genetic disease, a complete cure is not possible at present. Temporary relief is brought in by injecting the deficient protein identified through clinical diagnosis.

Question 35.
Explain the reason for sickle cell anaemia.
Answer:
The defects of genes may also cause deformities in the sequencing of amino acids which are the building blocks of haemoglobin. As a result of this, the structure of haemoglobin changes and this in turn decreases its oxygen carrying capacity.

Question 36.
How does the deformity of red blood cells in sickle cell anaemia patients affect their body?
Answer:
The defects of genes may also cause deformities in the sequencing of amino acids which are the
building blocks of haemoglobin. As a result of this, the structure of haemoglobin changes and this in turn
decreases its oxygen carrying capacity. The oxygen carrying capacity of red blood cells decreases. The
sickle shaped RBCs get collected in the blood vessels and block the flow of blood in them
Kerala Syllabus Class 10 Biology Solutions Chapter 4 Keeping Diseases Away 2

Question 37.
Explain cancer.
Answer:
Cancer is caused by the uncontrolled division of cells spreading to other tissues. The normal cells get transformed into cancerous cells when the control system of cell division fails.

Question 38.
How cancer becomes complicated?
Answer:
Various reasons such as environmental factors, smoking, radiations, virus, hereditary factors, and alterations in genetic material lead to the transformation of normal cells into cancer cells. The disease may become complicated with the spread of cancer cells to other parts of the body through blood and lymph.

Question 39.
How is cancer treated?
Answer:
Currently surgery, chemotherapy, radiation therapy, etc., are used in the treatment of cancer. It is difficult for the patients to recover if the disease becomes severe. Hence, early diagnosis of the disease is crucial in the treatment of cancer.

Question 40.
What are lifestyle diseases? Write the reasons also.
Answer:

Lifestyle diseases are caused by unhealthy living style. The changes in food habits, lack of physical exercise, stress, bad habits like consumption of alcohol, drug abuse, smoking, etc., lead to various lifestyle diseases.

  • Diabetes – deficiency of insulin or its malfunctioning
  • Fatty Liver – deposition of excess fat in the liver
  • Stroke- rupture’ of blood vessels in brain, block of blood flow
  • Hypertension – decrease in diameter of arteries due to deposition of fat
  • Heart attack – block of blood flow due to deposition of fat in coronary arteries, which carry blood to heart

Question 41.
How does smoking affect heart, lungs, and brain?
Answer:
Brain – Stroke, addiction to nicotine.
Lungs – Lung cancer, emphysema, bronchitis Heart – Hypertension, loss of elasticity of arteries, decrease in functional efficiency

Question 42.
Prepare a poster to make people aware of drug abuse.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 4 Keeping Diseases Away 3

Question 43.
Find out diseases which are affected by domestic animals and complete the table.
Answer:

Diseases Causative organisms Symptoms
Anthrax Bacteria Oozing of blood from nose and mouth
Foam and froth from mouth
Sudden occurrence of fever
Foot and mouth diseases Virus Severe fever
Boils in the mouth and between claws, which burst open .
Loss of appetite
Swelling of udder Bacteria Swelling of udder
Low yield of milk
Infection in the udder
Inflammation of nipple
Pullorum Poultry disease Bacteria Loose and white coloured excreta
Drowsiness
Block in breathing

Question 44.
Prepare an illustration related to plant diseases.
• Brown spots on leaves
• Leaves dry up
• Leaves shrink and become chaff
• Reduced yield
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 4 Keeping Diseases Away 4

Let Us Assess

Question 1.
Which among the following is not a bacterial disease? ,
a. Tuberculosis
b. Nipah
c. Diphtheria
d. Anthrax
Answer:
b. Nipah

Question 2.
“Food safety will be adversely affected with the spread of plant diseases. ”
a. Do you agree with this statement? Why?
b. Give two examples of plant diseases.
Answer:
a. I agree with this statement. Food safety can be ensured by the availability of food materials. Spread of plant diseases adversely affect the production of food materials.
b. Bunchy top of banana, Blight disease of paddy.

Question 3.
Prepare a pamphlet including the major measures to be taken to prevent rat fever.
Answer:
Leptospira is the bacteria that causes rat fever. The bacteria that comes out through the urine of rat, dog and certain other animals remain alive in stagnant water and moisture. Prevention of stagnation of water, avoid food which contains the urine of rat, keep the surroundings clean, engage in destroying rats, etc. help to prevent rat fever.

Question 4.
What is the importance of vaccination in preventing diphtheria?
Answer:
Antitoxins which act against the toxins are used to protect the uninfected cells. But, if the disease becomes severe, the patient cannot be recovered through medication. So vaccination is the best preventive method.

Question 5.
What health habits should be adopted to prevent lifestyle diseases?
Answer:
Lifestyle diseases are caused by unhealthy living styles. The changes in food habits, lack of physical exercise, mental stress, bad habits like consumption of alcohol, drug abuse, smoking, etc. lead to various lifestyle diseases. Avoiding junk foods and fast food, regular exercise, avoid the consumption of alcohol and drugs, avoid smoking, decreasing stress, etc. should be adopted to prevent lifestyle diseases

Kerala Syllabus 10th Standard Biology Guide

Kerala Syllabus Class 10 Biology Solutions Chapter 3 Chemical Messages for Homeostasis

Kerala Syllabus 10th Standard Biology Guide Chapter 3 Chemical Messages for Homeostasis

Question 1.
What is the speciality of endocrine system?
Answer:
The endocrine system is an organ system that works along with the nervous system to control and co-ordinate all activities in the body.

Question 2.
Endocrine glands are known as ductless glands. Write reasons.
Answer:
Hormones are chemical messengers that regulate cellular activities. Endocrine glands do not have particular ducts to carry hormones to various tissues. Hence they are known as ductless glands. Hormones are transported through blood.

Question 3.
Explain target cells.
Answer:
Hormones reach every cell in the body as they are transported by blood. But each hormone acts only upon those cells which have specific receptors. The cells which are acted upon by hormones are their target cells.

Question 4.
How do hormones affect cells?
Kerala Syllabus Class 10 Biology Solutions Chapter 3 Chemical Messages for Homeostasis 1
Answer:
Only those cells having specific receptors can receive a specific hormone. Each hormone molecule binds with the receptor to form a hormone-receptor complex. Following this, enzymes are activated within the cell and certain changes occur in cellular activities.

Question 5.
Where is insulin and glucagon produced?
Answer:
The beta cells in the islets of Langerhans, a special group of cells in pancreas secrete insulin and the alpha cells secrete glucagon.

Question 6.
Explain the action of insulin to prevent the rise in the level of glucose in blood.
Answer:
When the level of glucose in blood is high, the production of insulin increases. Insulin enhances cellular uptake of glucose molecules and converts glucose into glycogen in the liver and muscles. As a result, the glucose in blood becomes normal.

Question 7.
Explain the action of glucagon when the level of glucose in blood decreases.
Answer:
When the level of glucose in blood is low, the production of glucagon increases. Glucagon converts the glycogen stored in the liver to glucose and synthesizes glucose from amino acids. As a result, the glucose in blood becomes normal.

Question 8.
What is the normal level of glucose in blood?
Answer:
The normal level of glucose in blood is 70-110 mg / 100 mg.

Question 9.
How is the level of glucose in blood maintained while fasting?
Answer:
During fasting, the glucose in blood becomes low. In such situations, the alpha cells of islets of Langerhans in pancreas secrete glucagon. The glucagon converts the glycogen stored in the liver to glucose and synthesizes glucose from amino acids. Such actions help to maintain the blood glucose level tononnal.

Question 10.
What is the reason for increase in the level of glucose in blood.?
Answer:
Decreased production of insulin due to the destruction of beta cells or the inability of cells to utilize the insulin produced, raises the level of glucose in blood. Excess glucose in the blood is expelled through urine.

Question 11.
What is diabetes mellitus?
Answer:
Diabetes is clinically referred to as a condition when the level of glucose before breakfast is above 126mg/ 100ml of blood.

Question 12.
Write about the symptoms and reasons for diabetes.
Answer:
Increased appetite and thirst and frequent urination are the major symptoms of diabetes. Decreased production of insulin is the reason for diabetes.

Question 13.
Write the test to detect the presence of glucose in urine.
Answer:
Take 2ml of the urine in a test tube. Add 2ml Benedict solution into it. Heat for 2 minutes. Observe the change in colour. Formulate your inference by comparing the glucose indicator on the reagent bottle.

Question 14.
What is metabolism?
Answer:
The anabolic and catabolic processes taking place in the body are commonly referred as metabolism. Metabolic activities are also under the control of hormones.

Question 15.
Name the hormones secreted by thyroid gland.
Answer:
The thyroid gland secrets two hormones- thyroxine and calcitonin.

Question 16.
What are the functions of thyroxine?
Answer:
Thyroxine plays an important role in controlling life activities. Thyroxine increases energy production and raises the rate of metabolism. It also accelerates the growth and development of the brain in the foetal stage and infancy and regulates growth in children.

Question 17.
What are the problems due to thyroxine deficiency?
Answer:
Hypothyroidism is a condition in which the production of thyroxine decreases. The decrease in production of thyroxine during the foetal stage or infancy, hinders proper physical and mental development. This condition is Cretinism. Prolonged deficiency of thyroxine in adults leads to a condition called Myxoedema. Low metabolic rate, sluggishness, increase in body weight, hypertension and inflammation in body tissues are the major symptoms of this disorder.

Question 18.
What are the problems caused by excessive production of thyroxine?
Answer:
All the life activities controlled by thyroxine are accelerated due to the excessive production of thyroxine. This condition is known as hyper-thyroidism. The major symptoms are high metabolic rate, rise in body temperature, excessive sweating, increased heart beat, sleeplessness, weight loss, emotional imbalance, etc. Persistent hyperthyroidism may lead to Graves disease, characterised by bulging of the eyeballs.

Question 19.
How is iodine related to thyroid gland?
Answer:
Iodine is essential for the production of thyroxine. The production of thyroxine is obstructed in the absence of iodine. In an attempt to produce more thyroxine, the thyroid gland enlarges. This condition is called goitre.

Question 20.
What is the normal level of calcium in blood?
Answer:
The normal level of calcium in blood is 9-11 mg / 100 ml.

Question 21.
What is the role of calcitonin in regulating the level of calcium in blood?
Answer:
When the level of calcium in blood increases, thyroid gland secretes a hormone named calcitonin. It lowers the level of calcium in blood. This hor-mone helps in maintaining the level of calcium in blood by depositing excess calcium in bones and by preventing the mixing of calcium with blood from the bones.

Question 22.
What is the role of parathormone in regulating the level of calcium in blood?
Answer:
Parathyroid gland secretes a hormone called parathormone. The function of this hormone is to raise the level of calcium in blood. When the level of calcium in the blood decreases, parathormone helps in the reabsorption of calcium to the blood from the kidneys and also prevents the deposition of calcium in bones.

Question 23.
Complete the illustration showing the maintenance of the level of calcium in blood by the action of hormones.
Kerala Syllabus Class 10 Biology Solutions Chapter 3 Chemical Messages for Homeostasis 2
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 3 Chemical Messages for Homeostasis 3
A. Thyroid
B. Parathormone
C. Decrease
D. Depositing excess calcium in bones and by preventing the mixing of calcium with blood from the bones.
E. Helps the reabsorption of calcium to the blood from kidneys and also prevents the deposition of calcium in bones.

Question 24.
Write the importance of thymus gland.
Answer:
Thymus gland is very active during infancy but constricts as we reach puberty. The major function of this gland is to control the activities and maturation of lymphocytes which help to impart immunity. This gland secretes a hormone called thymosin.

Question 25.
Name the hormones secreted by the adrenal cortex.
Answer:
The outer part of the adrenal gland is known as the cortex which produces hormones namely cortisol, aldosterone and sex hormones.

Question 26.
Write the function of cortisol.
Answer:
The synthesis of glucose from protein and fat, controls inflammation and allergy, slows down the action of defence cells, are the functions of cortisol.

Question 27.
How does the maintenance of salt-water balance take place in the body?
Answer:
Aldosterone is produced from the cortex of adrenal gland. Aldosterone maintains the salt-water level by acting in kidneys.

Question 28.
Explain the functions of epinephrine and norepinephrine during emergencies.
Answer:
Epinephrine and norepinephrine are produced from the medulla, the inner part of Adrenal gland. Epinephrine acts along with the sympathetic nervous system during emergencies. We can resist or withdraw ourselves from such situations. In these situations, norepinephrine acts along with epinephrine. The action of epinephrine and norepinephrine prolongs the body activities for more time, when the sympathetic system gets stimulated.

Question 29.
How does melatonin help in maintaining the rhythm of our daily activities?
Answer:
Pineal gland secretes the hormone, melatonin which helps in maintaining the rhythm of our daily activities. The production of melatonin is high at night and low during the day. When the level of melatonin increases, we feel sleepy and when it decreases we wake up. Thus, this hormone regulates the rhythm of life. This hormone also controls reproductive activities of organisms with definite reproductive periods.

Question 30.
Describe the structure of pituitary gland.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 3 Chemical Messages for Homeostasis 4
Pituitary gland is a two lobed gland seen below the hypothalamus.

Question 31.
Prepare a table containing the hormones secreted by the anterior lobe of the pituitary gland and its function.
Answer:

Hormones secreted by the anterior lobe of the pituitary gland Function
Thyroid Stimulating Hormone (TSH) Stimulates the activity of the thyroid gland
Adreno Cortico Tropic Hormone (ACTH) Stimulates the activity of adrenal cortex
Gonado Tropic Hormone (GTH) Stimulates the activity of testes in males and ovary’ in females
Growth Hormone (GH) Somato Tropic Hormone (STH) Promotes the growth of the body
Prolactin Production of milk

Question 32.
Write the function of somatotropin.
Answer:
Somatotropin is secreted by the anterior lobe of pituitary gland. It promotes growth of the body during its growth phase.

Question 33.
Explain dwarfism, gigantism and acromegaly.
Answer:

  • If the production of somatotropin decreases during the growth phase, it causes dwarfism.
  • If the production of somatotropin increases during the growth phase, it leads to the excessive growth of the body. This condition is called gigantism.
  • Acromegaly is the condition caused by the excessive production of somatotropin after the growth phase. It is characterised by the growth of the bones on face, jaws and fingers.

Question 34.
The posterior lobe of pituitary gland is a storage centre. Write your opinion about this statement.
Answer:
This is a correct statement. The hormones oxytocin and vasopressin which are secreted from the posterior lobe of the pituitary are actually produced in the neuro-secretory cells of the hypothalamus. The posterior lobe of pituitary stores these two hormones and releases them into blood.

Question 35.
What is the function of oxytocin?
Answer:
Oxytocin facilitates child birth by stimulating the contraction of smooth muscles in the uterine wall. Oxytocin also facilitates lactation.

Question 36.
Explain the function of vasopressin in kidneys.
Answer:
Vasopressin helps in the reabsorption of water in kidneys. Thus vasopressin regulates the loss of water through urine.

Question 37.
Write the reason for excessive production of urine during the rainy season.
Answer:
The production of vasopressin is less during winter and rainy seasons. This decreases the reabsorption of water in the kidneys and thus the quantity of urine increases.

Question 38.
What is the role of vasopressin in preventing loss of water from the body?
Answer:
When the normal water level in blood decreases, the production of vasopressin increases. This increases the reabsorption of water in kidneys and thus the quantity of urine lowers.

Question 39.
What is diabetes insipidus?
Answer:
When the production of vasopressin decreases, the reabsorption of water in the kidney is decreased and excess amount of urine is eliminated. This condition is known as diabetes insipidus. Frequent urination, increased thirst, etc. are the symptoms

Question 40.
Explain the action of male sex hormones.
Answer:
The male sex hormone testosterone controls sperm production and secondary sexual characters in males such as change in voice, growth of hair, etc.

Question 41.
Write the action of female sex hormones.
Answer:
Ovary produces the female sex hormones namely estrogen and progesterone. Estrogen controls secondary sexual characters, ovulation, menstrual cycle, etc. Progesterone controls ovulation, menstrual cycle and implantation of embryo in the uterus.

Question 42.
Explain the influence of gonadotropic hormones in sex organs.
Answer:
Testes and ovary, the male and female sex organs respectively, secrete different types of hormones. Gonadotropic hormones from the pituitary regulate the development and functions of the sex organs.

Question 43.
Hypothalamus plays an important role in maintaining homeostasis. How?
Answer:
Vasopressin, oxytocin, releasing hormones and inhibitory hormones are secreted by hypothalamus. Vasopressin regulates the water level. Oxytocin facilitates child birth by stimulating the contraction of smooth muscles in the uterine wall and facilitates lactation. Releasing hormone stimulates the anterior lobe of the pituitary and secretes tropic hormones.

The tropic hormones are TSH which stimulates the activity of the thyroid gland, ACTH which stimulates the activity of adrenal cortex and GTH which stimulates the sex organs. The inhibitory hormone inhibits the production of tropic hormones in the anterior lobe of the pituitary gland, thus controls the activity of endocrine glands.

Question 44.
Write about pheromones and their function.
Answer:
Chemical substances that are secreted by certain animals to the surroundings to facilitate communication are called pheromones.
Pheromones help in attracting mates, informing the availability of food, determining the path of travel, signalling dangers, etc. The chemical messages of pheromones also help honey bees and termites to live in colonies. The muscone in the musk deer, the civeton in the civet cat, bombykol in the female silk worm moth, etc., are examples for pheromones.

Question 45.
What are plant growth regulators?
Answer:
There are certain chemical substances in plant cells to control and co-ordinate life activities as in animals. These are the plant hormones. These are also called plant growth regulators.

Question 46.
Prepare a table containing plant hormones and their functions.
Answer:

Plant hormone Function
Gibberellin Stimulates break down of stored food to facilitate germination, sprouting of leaves
Auxin Cell growth, cell elongation, promoting the growth of terminal buds, fruit formation.
Cytokinin Cell growth, cell division, cell differentiation.
Abscisic acid Dormancy of embryo, dropping of ripened leaves and fruits.
Ethylene Ripening of leaves and fruits, excess amount of ethylene causes dropping of leaves and fruits.

Question 47.
Prepare a short note on artificial plant hormones.
Answer:
Plant hormones are synthesized artificially by identifying the chemical structure of hormones. Use of such hormones has contributed a lot to the progress of the agricultural sector.

  • Auxins –
    It is used in the agricultural field to prevent the dropping of premature fruits, for the sprouting of roots and as a weedicide.
  • Gibberellins –
    It is used for increasing fruit size in grapes and apple and also for preventing ripening of fruits to assist marketing.
  • Ethylene –
    Ethylene is used for the flowering of pineapple plants at a time and for the ripening of tomato, lemon, orange, etc. Ethyphon, a chemical which is available in liquid form, gets transformed into ethylene, when used in rubber trees and it increases the production of latex.
  • Abscisic acid –
    It is used for harvesting fruits at the same time.

Let Us Assess

Question 1.
Identify the word-pair relationship to fill in the blank.
Thyroxine : Thyroid gland
Epinephrine : …………………
Answer:
Adrenal gland

Question 2.
Analyse the information given in the box and answer the questions.
X -The production of this hormone is more in night and less in day time.
Y -Hormones from the adrenal gland work along with the sympathetic system.

a. Identify and name the hormone ’X’ and its gland.
b. Identify the hormones indicated as ‘Y’.
Answer:
a. Melatonin, Pineal gland
b. Epinephrine (Adrenaline), Norepinephrine (Noradrenaline)

Question 3.
Analyse the illustration and complete the table appropriately.
Kerala Syllabus Class 10 Biology Solutions Chapter 3 Chemical Messages for Homeostasis 5
Kerala Syllabus Class 10 Biology Solutions Chapter 3 Chemical Messages for Homeostasis 6
Answer:

Gland Location Hormones
Hypothalamus Below the thalamus Oxytocin, Vasopressin, Releasing hormone, Inhibitory hormone
Pituitary Below the hypothalamus Tropic hormones (TSH, ACTH, GTH), Growth hormone, Prolactin
Thyroid In the throat just below the larynx. Calcitonin, Thyroxine
Parathyroid Behind the thyroid gland Parathormone
Thymus Just below the sternum Thymosin
Pancreas Below the stomach, near the duodenum Insulin, Glucagon
Ovary (female) On either side of uterus Estrogen, Progesterone
Testis (male) In the scrotum, outside the abdominal cavity Testosterone
Adrenal Above the kidneys Cortisol, Aldosterone, Sex hormones, Epinephrine, Norepinephrine
Pineal Centre of brain Melatonin

Question 4.
The hormone that helps in the reabsorption of water in the kidneys.
a. TSH
b. ACTH
c. ADH
d. GDH
Answer:
c. ADH

Kerala Syllabus 10th Standard Biology Guide

Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries

Kerala Syllabus 10th Standard Biology Guide Chapter 6 Unravelling Genetic Mysteries

Question 1.
Observe the picture.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 1
What are the features that the children show different from their parents?
Answer:

  • The hair of deer and cat differ from their parents.
  • The daughters have a different hair pattern from the mother.
  • The forehead and ear of the son are different from his mother.

Question 2.
Explain the terms heredity, variations and genetics.
Answer:
The transmission of features of parents to offsprings is termed as heredity. The features seen in offsprings that are different from their parents are called variations. The branch of science that deals with heredity and variations is called Genetics.

Question 3.
Why is Mendel considered as the Father of Genetics?
Answer:
Certain laws of inheritance, formulated by Gregor Johann Mendel, on the basis of hybridization experiments in pea plants, have led to the foundation of genetics. This is why Mendel is considered as the Father of Genetics.

Question 4.
What are the traits that were experimented by Mendel?
Answer:
Gregor Johann Mendel studied the inheritance of 7 pairs of contrasting traits in pea plants, scientifically known as Pisum sativum. He formulated the laws of inheritance by analysing the inheritance of characters like height of plants, position of flower, shape of seed, colour of seed coat, colour of cotyledon, colour of fruit and shape of fruit.

Question 5.
What are the contributions of Gregor Johann Mendel?
Answer:
Through Gregor Johann Mendel’s studies on inheritance, he explained that each character is controlled by a pair of factors, which he illustrated using symbols.

The illustration of the hybridization experiment conducted on the basis of two contrasting traits of the character height in pea plant. Here the factors are illustrated using symbols.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 2

Question 6.
Which character of pea plants is considered in this experiment?
Answer:
Height of plants

Question 7.
What are the contrasting traits of the character height?
Answer:
Tall and dwarf.

Question 8.
What are the traits those were apparent and not apparent in the first generation?
Answer:
Expressed trait – tall Hidden trait – Dwarf

Question 9.
Difference in the factors of tall parent plant and the first generation plant.
Answer:
Tallness in parent plant is controlled by the factor T. But in the first generation tallness is controlled by the factors T, t.
When plants that differ in a pair of contrasting traits are hybridized, only one trait is expressed while the other remains hidden in the offsprings of the first generation. The expressed trait is called dominant trait and the hidden trait is called recessive trait.

Question 10.
What are alleles?
Answer:
The gene present in the chromosome of the nucleus determines the character. A gene that controls a .trait has different forms. The different forms of a gene are called alleles. Generally, a gene has two alleles.

Question 11.
Which are the alleles of a tall plant?
Answer:
The alleles of a tall plant are ‘TT’.

Question 12.
Which are the alleles of a dwarf planet?
Answer:
The alleles of a dwarf plant are ‘tt’.

Question 13.
How are alleles represented?
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 3
Answer:
The different forms of a gene are called alleles. Generally a gene has two alleles. The different alleles of the gene that control the trait, height in the illustration of hybridization, given above are T and t. The allele T determines the trait tallness and the allele t determines the trait dwarfness. When we illustrate hybridization experiment, the allele that controls the dominant character that is expressed in the first generation is generally indicated by a capital letter and the allelle that controls recessive character is indicated by a small letter.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 4
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 5

Question 14.
Explain dominant trait and recessive trait.
Answer:
When plants that differ in a pair of contrasting traits are hybridized, only one trait is expressed while the other remains hidden in the offsprings of the first generation. The expressed trait is called dominant trait and the hidden trait is called recessive trait.

Question 15.
What are the characters of plants in the second generation and their factors?
Answer:
In second generation three plants were tall and one plant was dwarf.

Question 16.
Explain the characters of plants and their alleles in the second generation.
Ans:
Tall – 1 (TT), Tall – 2 (Tt), Dwarf – 1 (tt).

Question 17.
Recessive trait in the first generation and the second generation?
Answer:
The recessive trait in the first generation is expressed in the second generation.

Question 18.
Why does the recessive trait in the first generation appear in the second generation?
Answer:
Mendel came up with the assumption that during gamete formation, the factors that determine a particular character segregate without getting mixed; ie., half of the gametes formed from first generation plant Tt, contains T and the other half contains t.

Question 19.
What are the inferences formulated by Mendel from hybridization experiments?
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 6
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 8
Answer:
A character is controlled by the combination of two factors.
One trait is expressed (dominant trait) and the other trait remains hidden (recessive trait) in the offsprings of the first generation.
The traits that remain hidden in the first generation appear in the second generation.
The ratio of the dominant and the recessive traits in the second generation is 3 : 1.
Hybridization experiment conducted on two characters
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 7
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 9

Question 20.
What are the factors present in the gametes produced by first-generation?
Answer:
The factors present in the gametes produced by first-generation are, TR, Tr, tR, tr.

Question 21.
What are the characters in the plants of second-generation?
Answer:
Tall plant with round seed, Tall plant with wrinkled seed, Dwarf plant with round seed, Dwarf plant with wrinkled seed.

Question 22.
What are the characters different front parents that appeared in the second generation?
Answer:
The characters different from parents that appeared in the second generation are tall plant with wrinkled seed and dwarf plant with round seed.

Question 23.
What is the reason for the appearance of new combination of characters in offsprings that were not expressed in parents?
Answer:
Mendel explained that the appearance of variations in offsprings (characters not present in previous generation) is due to the independent assortment of each character.

Question 24.
Explain the double-helical model of DNA.
Answer:
Two scientists, James Watson and Francis Crick presented the double-helical model of DNA in 1953. This model got wide acceptance in the scientific world. As per the double-helical model, DNA contains two strands. A model of two long strands with sugar and phosphate and steps with nitrogen bases were suggested.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 10

Question 25.
What are nitrogen bases? Which are the nitrogen bases seen in DNA?
Answer:
Nitrogen bases are molecules that contain nitrogen and are alkaline in nature. DNA contains four kinds of nitrogen bases. They are adenine, thymine, guanine and cytosine.

Question 26.
What is the speciality seen in the pairing of nitrogen bases?
Answer:
Nitrogen bases which are the basic units of DNA are molecules with special features. In DNA, the base adenine pairs with thymine and guanine pairs with cytosine.

Question 27.
What are the components of nucleotides?
Answer:
DNA molecule is the repetitive unit of a deoxyribose sugar molecule, a phosphate molecule and a nitrogen base. This unit is called nucleotide. Since DNA has four kinds of nitrogen bases, DNA has four kinds of nucleotides too.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 11

Question 28.
Illustrate the arrangement of nucleotides in a DNA molecule.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 12

Question 29.
Write the differences between DNA and RNA.
Answer:

DNA RNA
1.Number of strands Double Single
2. Type of sugar Deoxyribose sugar Ribose sugar
3. Nitrogen bases Adenine, Adenine, Thymine, Uracil, Guanine, Guanine, Cytosine Cytosine

Question 30.
Prepare a short note on genes.
Answer:
The activity of particular proteins (enzymes) controls metabolic activities and is responsible for specific characteristics. Genes contain information for protein synthesis. Genes are particular segments of DNA.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 13

Question 31.
How do genes act? Explain.
Answer:
Genes which are the specific units of DNA control metabolic activities and they are responsible for specific characters. DNA does not participate directly in protein synthesis. RNA (Ribo Nucleic Acid) is the molecule that carries information from DNA to ribosomes and controls protein synthesis. Since this RNA is the messenger of DNA, it is called messenger RNA or mRNA. mRNA reaches ribosomes outside the nucleus. Different kinds of amino acids reach ribosomes.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 14

Question 32.
Write the difference between mRNA, tRNA, rRNA.
Answer:

  • mRNA – Since this RNA is the messenger of DNA, it is called messenger RNA or mRNA.
  • tRNA – tRNA (Transfer RNA) carries amino acids to the ribosome.
  • rRNA – rRNA (Ribosomal RNA) are seen associated with ribosomes.

Protein molecule is synthesized by adding amino acids as a result of all these activities.

Question 33.
Write note on human chromosomes.
Answer:
46 chromosomes are seen in humans. Among these, 44 chromosomes are autosomes (somatic chromosomes) and two chromosomes are sex chromosomes. An autosomal pair constitutes two identical chromosomes. Hence 22 pairs of autosomes are found in humans.

Question 34.
What are the sex chromosomes in humans?
Answer:
Sex chromosomes are of two types. They are called X chromosome and Y chromosome. Two X chromosomes are seen in female but an X chromosome and a Y chromosome are seen in male. That is, the genetic constitution of female is 44 + XX and that of male is 44 + XY.

Question 35.
What is crossing over of chromosomes?
Answer:
During the initial phase of meiosis, chromosomes pair and exchange their parts. This process is called crossing over of chromosomes.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 15

Question 36.
How does crossing over cause variation?
Answer:
As a result of crossing over, part of a DNA crosses over to become the part of another DNA. This causes a difference in the distribution of genes. When these chromosomes are transferred to the next generation, it causes the expression of new characters in offsprings.

Question 37.
How the combination of allele during fertilization causes variations in the next generation?
Answer:
The chromosomes of parents reach the offsprings through gametes. When gametes undergo fusion, the combination of allele changes. This causes the expression of characteristics in offsprings that are different from parents. Thus, fertilization causes variations in the next generation.

Question 38.
What is mutation?
Answer:
A sudden heritable change in the genetic constitution of art organism is called mutation.

Question 39.
What are the reasons for mutation?
Answer:
Mutation may occur due to the defects in the duplication of DNA, certain chemicals, radiations, etc.

Question 40.
What is the importance of mutation?
Answer:
Certain mutations are harmful and some are helpful for survival. Mutations lead to variations in characters. The effects of certain mutations are visible immediately while some are expressed after many generations. Mutation has great relevance in evolution.

Question 41.
Is there any difference in the number of chromosomes in male and female?
Answer:
46 chromosomes are seen in humans. Among these, 44 chromosomes are autosomes (somatic chromosomes) and two chromosomes are sex chromosomes. An autosomal pair constitutes two identical chromosomes. Hence 22 pairs of autosomes are found in humans. Sex chromosomes are of two types.

They are called X chromosome and Y chromosome. Two X chromosomes are seen in female but a X chromosome and a Y chromosome are seen in male. That is, the genetic constitution of female is 44 + XX and that of male is 44 + XY.

Question 42.
What is the possibility for the birth of a male or a female child?
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 16
The XY chromosomes of the father determine whether the child is male or female. Child with XX sex chromosomes is female and one with XY sex chromosomes is male.

Question 43.
What may be the reason for the difference in the colour of skin in people living in various parts of the world?
Answer:
Melanin, a pigment protein imparts colour to the skin. It can be assumed that the difference in gene function is the reason for the colour difference of skin.

Let Us Assess

Question 1.
The nitrogen base absent in RNA
a. Adenine
b. Thymine
c. Uracil
d. Cytosine
Answer:
b. Thymine

Question 2.
Arrange the stages of protein synthesis in the form of a flow chart.

  • combines amino acids
  • mRNA reaches ribosomes
  • mRNA is formed
  • amino acids are carried to the ribosomes

Answer:
mRNA is formed → mRNA reaches ribosomes → amino acids are carried to the ribosomes → combines amino acids.

Question 3.
Observe the hybridisation experiment given below.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 17
a. Prepare an illustration of this hybridization experiment using symbols.
b. Prepare an illustration for the second generation.
Answer:
a.
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 18
b. Self-pollination in first-generation
Kerala Syllabus Class 10 Biology Solutions Chapter 6 Unravelling Genetic Mysteries 19

Question 4.
Three processes that cause variations in new generations are given. Prepare a short note on each of the processes.

  • Crossing over of chromosome
  • Fertilization
  • Mutation

Answer:
Crossing over of chromosome – During the initial phase of meiosis, chromosomes pair and exchange their parts. This process is called crossing over of chromosomes. As a result of this, part of a DNA crosses over to become the part of another DNA. This causes a difference in the distribution of genes. When these chromosomes are transferred to the next generation, it causes the expression of new characters in offsprings.

Fertilization – The chromosomes of parents reach the offsprings through gametes. When gametes undergo fusion, the combination of allele changes. This causes the expression of characteristics in offsprings that are different from parents. Thus, fertilization causes variations in the next generation

Mutation – A sudden heritable change in the genetic constitution of an organism is called mutation. This may occur due to defects in the duplication of DNA, certain chemicals, radiations, etc. Mutations bring about changes in genes which can be transmitted over generations and thus leading to variations in characters. Mutations have great relevance in evolution.

Kerala Syllabus 10th Standard Biology Guide

Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge

Kerala Syllabus 10th Standard Biology Guide Chapter 2 Windows of Knowledge

Question 1.
Why are dogs more capable than human beings in tracking the injured. in such circumstances?
Answer:
The number of receptors influence the efficiency of sense organs. The number of receptors in the sense organs is different in different organisms. The surface of a postage stamp is enough to arrange all the olfactory cells in the nose of a human being. But a large scarf is required to arrange the olfactory cells of a dog.

Question 2.
List various sense organs and the stimuli they receive.
Answer:

Sense organ Receptors Stimuli
Eye Photoreceptors Light
Ear Auditory receptors Sound
Tongue Taste receptors Taste
Nose Olfactory receptors Smell
Skin Various receptors Touch, pain temperature, cold, pressure

Question 3.
Make a table to explain how eyes are protected.
Answer:

Eye socket (orbit) Protection of eyeball.
External eye musc1e Fix the eyeball in the orbit.
Eyebrow Protects the eyes from dust, sweat.
Eyelashes Protect the eyes from dust.
Eyelids Protect the eyes from dust and external shocks.
Conjunctiva Secretes mucus which protects the anterior portion of the eyeball from being dry.
Tears Clean and lubricate the anterior part of the eyeball.

Question 4.
Make a table containing important paris of eye, its peculiarities and functions.
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 1
Answer:

Parts Peculiarity Functions
Sclera Outermost layer, made up of connective tissues. Gives rigidity to the eyeball.
Choroid Middle layer which contains a large number of blood vessels. Gives nutrients and oxygen to the tissues of eye.
Retina The inner most layer of eye. Photoreceptors are seen. Images are formed.
Conjunctiva A thin membrane covers the front part of the eyeball except cornea. Protects the front part of eyeball.
Cornea Slightly projected transparent anterior part of the sclera. Refracts light rays to focus on retina.
Iris Part of the choroid seen behind the cornea. Presence of melanin prevents harmful light rays.
Pupil The aperture seen at the centre of the iris. Contracts and relaxes according to the intensity of light.
Lens Elastic transparent convex lens. Helps to focus light on retina.
Ciliary muscles Circular muscles seen around the lens. The contraction and relaxation of these muscles alter the curvature of lens.
Aqueous chamber The chamber between the lens and the cornea filled with watery fluid – aqueous humour. Gives nutrients to the lens and cornea.
Vitreous chamber The chamber between the retina and the lens; filled with jelly like fluid – vitreous humour. Gives shape to the eyeball.
Yellow spot The part of retina where plenty of photoreceptors are present. It is the point of maximum visual clarity.
Blind spot Photoreceptors are absent. The part of retina from where the optic nerve begins.
Optic nerve Nerve fibre connecting eyeball and brain. Transmits impulses from photo receptors to the visual centre in the brain.

Question 5.
Explain the changes which occur in the pupil based on the intensity of light.
Answer:
Light which passes through the cornea reaches the lens through an aperture called the pupil. The size of the pupil is regulated with the help of muscles in the iris. The pupil dilates in dim light and constricts in bright light. Thus the amount of light falling on the lens is regulated according to the intensity of light.

Question 6.
What is the role of circular muscles and radial muscles in regulating the size of pupil?
Answer:
The size of the pupil is regulated by the action of circular muscles and radial muscles. When the radial muscles contract in dim light, the size of the pupil increases. When the circular muscles contract in intense light, the size of the pupil decreases. Thus the amount of light falling on the lens is regulated according to the intensity of light.

Question 7.
What are the peculiarities of image formed?
Answer:
Real, small, inverted.

Question 8.
Write down the features of the eye that help to view near and distant objects.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 4
While viewing near objects, the curvature of lens increases. As a result, the focal length decreases. The contraction of ciliary muscles and relaxation of ligaments help to increase the curvature of lens.
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 5
While viewing distant objects, the curvature of lens decreases. As a result, focal length increases. The relaxation of ciliary muscles and stretching of ligaments help to decrease the curvature of lens.

Question 9.
What is the power of accommodation of the eye?
Answer:
The capacity of the eye to change the curvature of lens depending on the distance between the eye and the object by adjusting the focal length is called the power of accommodation of the eye.

Question 10.
Name the photoreceptors in the eye. How do they differ from one another?
Answer:
The two photoreceptors present in the retina of the eye are rod cells and cone cells. Rod cells are more in number than cone cells. Rod cells have the shape of a rod and cone cells are cone shaped. Rod cells contain visual pigment called rhodopsin and in cone cells the pigment is photopsin (iodopsin). Rod cells are highly photosensitive and since they are activated even in very dim light, we are able to see objects in dim light. The cone cells provide us with colour vision.
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 6

Question 11.
Prepare a short note on the diversity of cone cells.
Answer:
Three types of cone cells which help us to detect three primary colour of light-red, green and blue are present in our eyes. This is due to the change in amino acid in the opsin molecule.

Question 12.
Explain the function of cone cells and rod cells.
Answer:
The visual pigment seen in cone cell is photopsin (iodopsin) and rod cell is rhodopsin. Both these pigments are formed from a protein named opsin and retinal which is a derivative of Vitamin A. When light rays fall on pigments present in photoreceptors, the pigments dissociate into retinal and opsin. This chemical change leads to the formation of impulses.

Question 13.
How is vision enabled?
Answer:
The visual pigment seen in cone cell is photopsin (iodopsin) and rod cell is rhodopsin. When light rays fall on pigments present in photoreceptors, the pigments dissociate into retinal and opsin. This chemical change leads to the formation of impulses. These impulses are transmitted to cerebrum through the optic nerves and this enables vision.

Question 14.
Prepare a flow chart showing the process of ‘ vision.
Answer:
Light → Cornea → Aqueous humour → Pupil → Lens→ Vitreous humour → Retina → Impulse → Optic nerve → Cerebrum → Sense of sight

Binocular vision
The activity to feel binocular vision:
Stretch your left hand forward. Close your right eye and focus the forefinger of your left hand. Now close your left eye and without changing the direction of your head, focus the I same finger. You can feel the change in the position of finger.

Question 15.
What is binocular vision?
Answer:
The images from two sides of the same object are formed in the left and right eye. These two images are combined together in the visual area of our brain to form a three dimensional image of the object. This is called binocular vision.

Question 16.
What is the difference between night blindness and xerophthalmia?
Answer:

The deficiency of Vitamin A results in the low production of retinal. This in turn creates the deficiency of rhodopsin in rod cells. The resynthesis of rhodopsin also gets blocked. This causes a condition called night blindness. Persons with night blindness cannot see objects clearly in dim light.

Due to the prolonged deficiency of Vitamin A, the conjunctiva and cornea will become dry and opaque. This condition is called xerophthalmia.

Question 17.
Prepare a note on the eye defects and diseases.
Answer:

Night blindness:
The retinal, a part of the visual pigment, is derived from Vitamin A. The deficiency of Vitamin A results in the low production of retinal. This in turn prevents the resynthesis of rhodopsin. In this condition, objects cannot be seen clearly in dim light and this disease is called night blindness.

Xerophthalmia:
If there is a prolonged deficiency of Vitamin A, the conjunctiva and cornea become dry and opaque. This causes xerophthalmia and leads ultimately to blindness.

Colour blindness:
Retina contains cone cells which can detect red, green, and blue colours. Colour blindness is caused due to the defect of cone cells which detect red and green colours. Persons with this defect cannot distinguish green and red colours.

Glaucoma:
If the reabsorption of aqueous humour does not occur, it causes an increase in the pressure inside the eyes which causes a defect called glaucoma. This causes damage to the retina and the photoreceptor cells and ultimately leads to blindness. This defect can be rectified by laser surgery.

Cataract: It is a condition in which the lens of the eyes become opaque resulting in blindness. This can be rectified by replacing the lens with an artificial one, through surgery.

Conjunctivitis:
This is an infection of the conjunctiva. The causative organisms may be bacteria, virus, etc. This disease is transmitted through contact and can be prevented by maintaining personal hygiene.

Question 18.
Food materials rich in Vitamin A and health of the eye
Answer:
The retinal, a part of the visual pigment, is derived from Vitamin A. The deficiency of Vitamin A results in the low production of retinal. This in turn prevents the resynthesis of rhodopsin. So food containing vitamin A is necessary for the health of eye.

Question 19.
Excessive use of mobile, computer, etc and health of the eye.
Answer:
The problems of the eyes caused by the excessive use of cell phones, computer, tablet, etc is called computer vision syndrome. The continuous use of such devices affects the ability of the eye to focus. Headache is its major symptom. Drying of the eye, high pressure in the eye, etc are other symptoms.
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 7

Question 20.
Write the functions performed by ear.
Answer:
Ear helps us in hearing and maintaining the balance of the body.

Question 21.
What are the parts and their function of the externa1 ear?
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 8
Answer:
Pinna – Carries sound waves to the auditory canal.
Auditory canal –
Carries sound waves to the tympanum. Small hairs and wax present inside the canal help to prevent dust and foreign particles from entering the ear.
Tympanum –
A thin circular membrane that separates the middle ear from . the external ear. It vibrates in resonance with sound waves.

Question 22.
What are the parts of middle ear?
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 9
Answer:
Ear ossicles (Malleus, Incus, Stapes), Eustachian tube are the parts of middle ear.

Question 23.
Explain the function of ear ossicles.
Answer:
Malleus, incus and stapes are the bones seen in ear ossicles. The ear ossicles connect the tympanum to the internal ear through the oval window. Ear ossicles amplify and.transmit the vibrations of tympanum to the internal ear.

Question 24.
What is the peculiarity of Eustachian-tube?
Answer:
Eustachian tube connects middle ear and pharynx. It helps in maintaining balance of pressure on either side of the tympanum.

Question 25.
Write the features of labyrinth seen in internal ear.
Answer:
The internal ear is situated inside a bony case in the skull called the bony labyrinth. In this bony case, there are membraneous labyrinths as well.

Question 26.
What are the fluids seen in internal ear?
Answer:
The space inside the membraneous labyrinth is filled with a fluid named endolymph. The space between the membraneous and bony labyrinth is filled with a fluid called perilymph.

Question 27.
Write the main parts and function of internal ear.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 10
Semicircular canals, vestibule and cochlea are the main parts of the internal ear. Semicircular canals and vestibule help in balancing the body whereas cochlea helps in hearing.

Question 28.
Explain oval window and round window.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 11

  • Oval window is a membrane seen attached to the stapes. Spreads the vibration of ear ossicles to the inner ear.
  • Round window helps in the movement of fluid inside the cochlea

Question 29.
How is hearing possible?
Answer:
Cochlea is a coiled tube like a snail shell. It consists of three chambers. Specialized sensory hair cells which are present in basilar membrane that separate the middle and lower chambers, function as auditory recepttjrs. The sound waves which pass through the external ear vibrate the tympanum.

This vibration of the tympanum is transmitted to the ear ossicles which causes the vibration of the membrane in the oval window. This vibration causes the movement of fluid inside the cochlea. As a result, the sensory hair cells seen in the basilar membrane of the cochlea are stimulated and impulses are generated. These impulses reach the cerebrum through the auditory nerve and hearing is effected.

Question 30.
Prepare a flow chart related to the process of hearing.
Answer:
Pinna → Auditory canalTympanum → Ear ossicles → Oval window → Cochlea → Hair cells → Impulse → Auditory nerve → Cerebrum → Sense of hearing.

Question 31.
What are the parts of the internal ear which help in body balancing?
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 12
Vestibule and the three semicircular canals play a major role in body balancing.

Question 32.
Explain the maintenance of body balancing?
Answer:
Body balance is maintained in accordance with the movement of the head. Movements of the head bring about the movement of the endolymph present inside the vestibule and the semicircular canals. This causes movement of the sensoiy hair cells and generates impulses. These impulses are transmitted by the vestibular nerves to the cerebellum, and the equilibrium of tl maintained.

Question 33.
How are the taste buds arranged on the tongue?
Answer:
Chemoreceptors seen inside the mouth and tongue help us to detect taste. These are seen mainly on the surface of the tongue. The projected structures seen on the surface of the tongue are called papillae. The parts seen on the papillae that detect taste are the taste buds. We have taste buds that are stimulated by tastes like sweet, salt, sour, bitter, umami, etc.

Question 34.
How do we experience taste?
Answer:
Substances responsible for taste dissolve in saliva, stimulate the chemoreceptors and generate impulses. These impulses reach the brain through the respective nerves and we experience taste.

Question 35.
How do we detect smell?
Answer:
The smell of various substances diffuse in the air and enter the nostrils along with the inhaled air. These aromatic particles dissolve in the mucus inside the nostrils, stimulate olfactory receptors and generate impulses. These impulses from olfactory receptors reach the cerebrum and smell is detected.

Question 36.
What are the receptors in the skin to receive stimuli?
Answer:
Touch receptor, pressure receptor, cold receptor, temperature receptor and pain receptor.

Question 37.
Are the receptors uniformly distributed all over the skin? Prove.
Answer:
The receptors are not uniformly distributed all over the skin. This can be proved by the following activity. Take two refillers of any ball point pen. Ask your friend to close his/her eyes and stretch his/her hand. Place two pointed tips of the refiller firstly at the fingertip and then at the wrist of your friend. The touch receptors are seen more in finger tip. The touch in finger tip is experienced in two points and the touch in hand is experienced in a single point.

Question 38.
Explain about the receptors seen in planaria, housefly, shark and snake.
Answer:
In planaria, the eye spot helps to detect light. The eyes of a housefly consist of cluster of photoreceptors called ommatidia. In shark, lateral lines are seen. There are receptors in the lateral line on either side of the body which help to detect the change in the balance of body. In shark, highly sensitive olfactory receptors are also present. The aromatic particles that stick on the tongue of snake reach Jacobson’s organ seen on the roof of the mouth cavity. The olfactory receptors seen there get stimulated.

Let Us Assess

Question 1.
While viewing nearby objects
a. Ciliary muscles relax
b. Curvature of lens decreases
c. Ciliary muscles contract
d. Focal length increases
Answer:
c. Ciliary muscles contract

Question 2.
Identify the odd one and write down the common feature of others.
Malleus, Eustachian tube, Stapes, Incus
Answer:
Eustachian tube
Others are bones in ear ossicles.

Question 3.
Redraw the figure. Identify the parts
according to the hints and label them.
Hints:
a. The part where the muscles that regulate the size of the pupil are seen.
b. Jelly like fluid.
c. The layer of eye where photoreceptors are seen.
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 13
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 14

Question 4.
Figure of Ear is given. Redraw it and name and label the parts mentioned.
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 15
a. Part that receives the vibrations of the eardrum.
b. The tube that connects the pharynx.
c. Part where the auditory receptors are seen.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 2 Windows of Knowledge 16
a. Ear ossicles
b. Eustachian tube
c. Cochlea

Kerala Syllabus 10th Standard Biology Guide

Kerala Syllabus Class 10 Biology Solutions Chapter 7 Genetics for the Future

Kerala Syllabus 10th Standard Biology Guide Chapter 7 Genetics for the Future

Question 1.
How are insulin-producing bacteria created?
Answer:
Cut the gene responsible for the production of insulin in humans. Cut bacterial DNA (plasmid), then join the gene responsible for the production of insulin in humans in bacterial DNA. Insert this DNA in the bacterial cell. Thus insulin producing bacteria are created.

Question 2.
What is the change that occurred in the genetic constitution of the bacteria that produce insulin?
Answer:
Cut the gene responsible for the production of insulin in humans. Cut bacterial DNA (plasmid). Then join the gene responsible for the production of insulin in humans in bacterial DNA. The genetic constitution of the bacteria get changed.

Question 3.
Will the future generation of this bacteria have the ability to produce insulin? Why?
Answer:
Provide a favourable medium for the multiplication of bacteria that has the change in genetic constitution. Bacteria produce inactive form of insulin. From inactive insulin active insulin is produced. Thus the future generation of bacteria show the ability to produce insulin.

Question 4.
What are traditional methods of biotechnology?
Answer:
From BC 4000 onwards organisms like yeast, a kind of fungus, were used to prepare food items like bread. The ability of fungi and bacteria to convert sugar into alcohol was utilised to make wine, appam and cake. These can be considered as traditional methods of biotechnology.

Question 5.
What is biotechnology?
Answer:
The use of microorganisms and biological processes for industrial purpose is called Biotechnology.

Question 6.
What is genetic engineering?
Answer:
Genetic engineering is the technology of controlling traits of organisms by bringing about desirable changes in the genetic constitution of organisms.

Question 7.
What is the basis of genetic engineering?
Answer:
The basis of genetic engineering is the discovery of the fact that genes can be cut and joined.

Question 8.
Explain molecular scissors and molecular glue.
Answer:
The enzyme which is used for cutting genes are called molecular scissors. Restriction endonuclease is an example. The enzyme which is used for joining genes are called molecular glue. Ligase is an example of ‘ genetic glue ’.

Question 9.
How do new genes become a part of the genetic constitution of target cells?
Answer:
Suitable vectors are used to transfer genes from one cell to another. Bacterial DNA is generally used as vectors. DNA with ligated genes enter the target cell. Thus new genes become a part of the genetic constitution of target cells.

Question 10.
What are the scope of genetic engineering?
Answer:
Gene therapy, Genetically modified animals and
crops, Forensic test are the major scopes of genetic engineering.

Question 11.
Why is gene therapy essential?
Answer:
Genetic engineering has made a great leap in the treatment of genetic diseases. Gene therapy is a method of treatment in which the genes that are responsible for diseases are removed and normal functional genes are inserted in their place. This has triggered great hope in the control of genetic diseases.

Question 12.
What is the relevance of the human genome project?
Answer:
Even though science has progressed a lot, we couldn’t control genetic diseases. The reason for this is that we could not identify the exact gene and its location which is responsible for each trait. In 1990, the Human Genome Project was started as an attempt to solve the issue.

As a result of experiments conducted in various laboratories of the world until 2003, the secrets of human genome were revealed. With this, we can identify the location of a gene in the DNA, responsible for a particular trait.

Question 13.
What is the benefit of gene mapping?
Answer:
The technology known as gene mapping helped to identify the location of a gene in the DNA responsible for a particular trait. Gene mapping leads to gene therapy.

Question 14.
Explain the term genome, junk genes.
Answer:
The sum of genetic material present in an organism is called its genome. In human DNA, majority of genes, except the genes that code for protein are non-functional. They are called junk genes.

Question 15.
What are the major findings of human genome project?
Answer:

  • Human genome has about 24000 functional genes.
  • Major share of human DNA includes junk genes.
  • There is only 0.2 per cent difference in DNA among humans.
  • About 200 genes in human genome are identical to those in bacteria.

Question 16.
Prepare a short note on the proteins that can be used for the treatment of diseases in humans are produced through genetic engineering?
Answer:
Interferons is the protein required for treatment of viral diseases, Insulin is used for the treatment of diabetes, Endorphin is a protein required for treatment of the symptom pain, Somatotropin is a protein required for treatment growth disorders.

Question 17.
How genetic modification is possible?
Answer:
Genetic engineering has progressed a lot more from biotechnology. Today, genetic modification in organisms can be implemented more effectively. This is made possible through the insertion of gene that code for desirable characters into the genetic constitution of an organism.

Question 18.
Write a short note on pharm animals.
Answer:
One of the future promises of genetic engineering is pharm animals: Genes responsible for the production of insulin and growth hormones required for humans are inserted into animals like cow, pig etc, transforming them into pharm animals. There are certain limitations in producing insulin using bacteria. The most important hurdle in this field is the culturing of bacteria. Researches in this field show that instead of this, medicines can be extracted from the blood or milk of, genetically modified animals.

Question 19.
Prepare a short note on the genetic modification in plants?
Answer:
Genetic modification is implemented not only in animals but in plants also. Today, insect-resistant plants like Bt brinjal, soybean, cotton, maize etc are common.

Question 20.
What are the things should be ensured while genetic modification carried out?
Answer:
When genetic modification is carried out in organisms, it should be ensured that there are no harmful consequences to humans or nature.

Question 21.
Explain DNA profiling.
Answer:
The technology of testing the arrangement of nucleotides is DNA profiling. Like the difference in the fingerprint of each person, the arrangement of nucleotides in each person also differs. Hence this technology is also called DNA fingerprinting.

Question 22.
What is the basis of DNA testing?
Answer:
The arrangement of nucleotides in the DNA of each person differs. This finding is the basis of DNA testing.

Question 23.
How are relations identified through DNA testing?
Answer:
The arrangement of nucleotides among close relatives have many similarities. So DNA fingerprinting is helpful to find out hereditary characteristics.

Question 24.
What is the scope of DNA testing?
Answer:
Certain experiments conducted by the scientist Alec Jeffrey in 1984 paved the way for DNA testing. DNA fingerprinting is helpful to find out hereditary characteristics, to identify real parents in cases of parental dispute and to identify persons found out after long periods of missing due to natural calamities or wars.

DNA of the skin, hair, nail, blood and other body fluids obtained from the place of murder, robbery, etc., is compared with the DNA of suspected persons. Thus, the real culprit can be identified from among the suspected persons through this method.

Question 25.
Prepare a short note on the misuse and side effects of genetic engineering.
Answer:
Genetic modification – Genetic modification is an intrusion upon the freedom of living beings and it is a violation of rights. It is criticized that genetically modified varieties cause haim to indigenous varieties and may cause health issues to humans.
Bio-weapons – Application of genetically modified pathogens and its multiplication through biotechnology’ upon enemies ‘is called Bioware. This becomes a threat to the existence of human beings.

Let Us Assess

Question 1.
Which of the following is not a part of modern genetic engineering?
a. DNA profiling
b. Gene mapping
c. DNA fingerprinting
d. X-ray diffraction
Answer:
d. X-ray diffraction

Question 2.
Gene therapy 1c an example of the benefits of science for human existence.
a. What is gene therapy?
b. What was the discovery that led to gene therapy?
c. How does gene therapy become useful to human beings?
Answer:
a. The sum of genetic material present in an organism is called its genome. We can cure genetic diseases by removing disease-causing genes from the genome and inserting normal functional genes. This method of treatment is called gene therapy.

b. The technology known as gene mapping helped to identify the location of a gene in the DNA responsible for a particular trait. Gene mapping leads to gene therapy.

c. We can cure genetic diseases by removing disease-causing genes from the genome and inserting normal functional genes.

Question 3.
Since genetic engineering has many harmful effects, it can t be promoted’. Do you agree with this statement? Why?
Answer:
I do not agree with this statement. We must use science and technology as a means to overcome the challenges faced by human beings. Science and technology are the products of human thought. We can justify this only if they are utilized for human benefit.

Kerala Syllabus 10th Standard Biology Guide

Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses

Kerala Syllabus 10th Standard Biology Guide Chapter 1 Sensations and Responses

Question 1.
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 1
List the variety of experiences experienced by the children and other organisms in the picture.
Answer:

  • A child tasting a mango.
  • A snail withdrawing its body into the shell when it ¡s touched.
  • Butterfly sipping nectar from flowers.
  • The chirping of birds.
  • The gentle pat of the breeze.
  • The birds fly away on hearing sound.
  • Enjoying colourful scenes
  • The intoxicating fragrance of flowers.
  • Washing the face using cold water.

Question 2.
What are the factors to which children and organisms respond in the picture?
Answer:

  • Touch
  • Sound
  • Taste
  • Light
  • Smell

Question 3.
What are stimuli?
Answer:
The senses that evoke responses in organisms are called stimuli.

Question 4.
What are the differences between internal and external stimuli?
Answer:
The senses from our immediate surroundings that evoke responses in organisms are called external stimuli. The stimuli that are formed inside the body are called internal stimuli. Hunger and thirst are examples for internal stimuli.

Question 5.
What are receptors.? Write its function also.
Answer:
There are specialized cells in the sense organs and other parts of the body to receive stimuli. These cells are known as receptors. They receive stimuli and generate suitable impulses.

Question 6.
What are the functions of nervous system?
Answer:
Normally, responses occur when the impulses generated by the receptors on receiving the stimuli reach the brain. The nervous system controls and co-ordinates these actions.

Question 7.
What are the major parts of nervous system?
Answer:
Brain, spinal cord and nerves are the major parts of nervous system.

Question 8.
Explain neuron.
Answer:
Neuron or nerve cell is the basic structural unit of the nervous system. Like all other cells, the neuron has a cell membrane, cytoplasm and nucleus.

Question 9.
Write the important parts, peculiarities and functions of neuron.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 2

Main parts Peculiarities Functions
Cell body (cyton) It is the main part of neuron. It contains a nucleus and cytoplasm. It carries impulses from the dendron to axon.
Dendron Short filament from the cell body. It carries impulses from dendrites to the cell body.
Dendrite Branches of dendron. Receives impulses from the adjacent neuron.
Axon Longest filament from the cell body. Carries impulses from the cell body to outside.
Axonite Terminal branches of axon. Carries impulses to the synaptic knob.
Synaptic knob Tip of axonite. Secretes neurotransmitter

Question 10.
What is myelin sheath?
Answer:
Axons of most of the neurons are repeatedly encircled by myelin, a membrane containing lipid. This is called myelin sheath.

Question 11.
Explain the formation of myelin sheath.
Answer:
Nerve is a group of axons. Myelin sheath in the nerves is formed of Schwann cells. Myelin sheath in the brain and the spinal cord is. formed of specialized cells called oligodendrocytes.
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 3

Question 12.
What is the difference between grey matter and white matter?
Answer:
The myelin sheath has a shiny white colour. The part of the brain and the spinal cord where myelinated nerve cells are present in abundance is called white matter and the part where nonmyelinated nerve cells are present is called grey matter.

Question 13.
What are the functions of myelin sheath?
Answer:
The major functions of the myelin sheath are to provide nutrients and oxygen to the axon, accelerate impulses, act as an electric insulator and protect the axon from external shocks.

Question 14.
Explain how impulses are transmitted through neurons.
Answer:
The outer surface of the plasma membrane of the neuron is positively charged and the inner surface is negatively charged. This is due to the difference in the distribution of certain ions. Impulses are messages conducted through nerves. These impulses transmit in the form of electric charges. Impulses are generated when stimuli evoke changes in polarity in the plasma membrane of receptors, the modified neurons.

The difference in the distribution of ions helps to maintain positive charge on the outer surface and negative charge inside the plasma membrane of the neuron. When stimulated, the ionic equilibrium in the particular part changes. As a result, polarity changes and the outer surface becomes negatively charged while the inner surface becomes positively charged. This change does not persist for long. It regains its original state. But the momentary charge difference in the axon membrane stimulates its adjacent parts and similar changes occur there too.

As this process proceeds, impulses get transmitted through axon. When stimulated, the distribution of ions in that particular part changes and hence the inner surface becomes positively charged and the outer surface becomes negatively charged . This momentary charge difference stimulates its adjacent parts and similar changes occur there too. As this process proceeds, impulses get transmitted as electric charges. Nerve impulses are messages transmitted through the neurons.
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 4

Question 15.
What is meant by synapse?
Answer:
Synapse is the junction between two neurons or a neuron and a muscle cell or a neuron and a glandular cell. Synapse helps to regulate the speed and direction of impulses.

Question 16.
How do impulses pass through synapse?
Answer:
When electric impulsesfrom the axon reach the synaptic knob, certain chemical substances are secreted from there to the synaptic cleft. These chemical substances are called neurotransmitters. They stimulate the adjacent dendrite or cell and new electric impulses are generated.
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 5

Question 17.
What are the different types of synapse?.
Answer:
Synapse is the junction between two neurons or a neuron and a muscle cell or a neuron and a glandular cell.
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 6

Question 18.
Prepare a flow chart of impulses passing through a neuron.
Answer:
Stimulus → Dendrite → Dendron → Cell body → Axon → Axonite → Synaptic knob → Synapse → Dendrite of adjacent neuron.

Question 19.
What are the different types of neuron?
Answer:
On the, basis of the direction of impulse, neurons can be classified into sensory neurons and motor neurons. Sensory neurons carry impulses to the brain and spinal cord. Motor neurons carry impulses from the brain and spinal cord to various parts of the body.

Question 20.
What are nerves? Which are they? Write their peculiarities and functions.
Answer:
Nerves are groups of axons or nerve fibres covered by connective tissue. On the basis of their functions, nerves are further classified into three.

a. Sensory nerve: Formed of sensory nerve fibres. It carries impulses from various parts of the body to the brain and the spinal cord.
eg: Optic nerve

b. Motor nerve: Formed of motor nerve fibres. It carries impulses from brain and spinal cord to various parts of the body.
eg: Hypoglossal nerve

c. Mixed nerve: Formed of sensory nerve fibres and motor nerve fibres. It carries impulses to and from the brain and spinal cord.
eg: Vagus nerve
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 7

Question 21.
How is nervous system classified? Write the peculiarities of each part.
Answer:
The nervous system consists of two parts, namely the central nervous system and the peripheral nervous system. The central nervous system consists of brain and the spinal cord. The peripheral nervous system consists of 12 pairs,of cranial nerves and 31 pairs of spinal nerves.
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 8

Question 22.
Prepare a short note about the protection of brain.
Answer:
The brain is protected inside the skull. It is covered by the meninges, a three-layered membrane. The cerebrospinal fluid is filled within the inner membranes of meninges and the ventricles of the brain.

Question 23.
What are the functions of cerebrospinal fluid?
Answer:
The cerebrospinal fluid is filled within the inner membranes of meninges and the ventricles of the brain. The cerebrospinal fluid is formed from the blood and is reabsorbed into the blood. The functions of the cerebrospinal fluid are to provide nutrients and oxygen to the tissues of the brain, regulate the pressure inside the brain and to protect the brain from injuries.

Question 24.
Explain the main parts and functions of brain.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 9
Cerebrum:
Cerebrum is the largest part of the brain and it has numerous fissures and folds. In cerebrum grey matter is seen in the external cortex and white matter is seen in the internal medulla. Cerebrum is the centre of thought, intelligence, memory and imagination. Cerebrum also evokes sensations and controls voluntary movements.

Cerebellum:
Cerebellum is the second largest part of the brain. It is seen behind the cerebrum as two flaps and has fissures, and grooves. Cerebellum coordinates muscular activities and maintains the equilibrium of the body.

Medulla oblongata :
The rod shaped medulla oblongata is seen below the cerebrum, located near to cerebellum. Medulla oblongata controls involuntary actions like heart beat, breathing, etc.

Thalamus :
Thalamus is situated below the cerebrum. It acts as relay station of impulses to and from the cerebrum. Thalamus analyses impulses from the various parts of the body and sends the important ones to the cerebrum.

Hypothalamus:
Hypothalamus is situatedjust below the thalamus and plays a major role in the maintenance of homeostasis.

Question 25.
What is the necessity of wearing helmets while riding two wheelers?
Answer:
Wearing helmets while riding two wheelers reduces the impact of accident. About 70% to 80 % of death in two wheeler accident is due to the injury of brain

Question 26.
How is the spinal cord protected?
Answer:
The spinal cord is protected inside the vertebral column. Like the brain, the spinal cord is also covered by meninges.

Question 27.
How does the dorsal root differ from ventral root?
Answer:
A dorsal root and a ventral root join to form a spinal nerve. Sensory impulses reach the spinal cord through the dorsal root. Motor impulses go out of the spinal cord through the ventral root.
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 10

Question 28.
Write about the major functions of the spinal cord.
Answer:
Impulses from different parts of the body are transmitted to and from the brain through the spinal cord. It also coordinates the repeated movements during walking, running, etc.

Question 29.
What are reflex actions? Write examples also.
Answer:
The accidental and involuntary responses towards stimuli are called reflex actions.
eg:

  • Sudden withdrawal of leg while touching a thorn.
  • We blink our eyes when objects come towards our eyes.

Question 30.
Explain reflex arc.
Answer:
Reflex arc is the pathway of impulses in the reflex action.

Question 31.
Prepare a flow chart related to reflex arc.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 11

Question 32.
What is the difference between spinal reflex and cerebral reflex?
Answer:
Mainly spinal cord acts as the centre of reflex action and such reflexes are called spinal reflexes, eg: Sudden withdrawal of leg while touching a thorn.
But all reflexes are not under the control of the spinal cord. Reflexes under the control of the cerebrum are called cerebral reflexes.
eg: We blink our eyes when light suddenly falls on our eyes.

Question 33.
Is it advisable to lift up people quickly by holding their arms or legs in an accident?
Answer:
It is not advisable to lift up people quickly by holding their arms or legs in an accident, because these actions may lead to injuries in spinalcord.

Question 34.
What are the changes that take place in the body during emergency situations?
Answer:
Heart beat increases, breathing rate increases, body shivers and the production of saliva decreases.

Question 35.
Explain autonomous nervous system.
Answer:
Activities that take place beyond the conscious level are controlled by the autonomous nervous system, a part of the peripheral nervous system. The autonomous nervous system contains the sympathetic system and the parasympathetic system.

Question 36.
Write the action of sympathetic and parasympathetic systems during emergency situations.
Answer:
Kerala Syllabus Class 10 Biology Solutions Chapter 1 Sensations and Responses 12

Organ Sympathetic system Parasympathetic system
Eye The pupil in the eye dilates The pupil constricts
Salivary gland Production of saliva decreases Production of saliva increases
Lung Trachea dilates Trachea constricts
Heart Heartbeat increases Heartbeat becomes normal
Stomach Gastric activities slow down Gastric activities become normal
Liver Glycogen is converted to glucose Glucose is converted to glycogen
Intestine Peristalsis slows down Peristalsis becomes normal
Urinary bladder Urinary bladder retains to normal state Urinary bladder contracts

Question 37.
Prepare a note on the diseases affecting the nervous system.
Answer:
Alzheimer’s:
Caused by the accumulation of an insoluble protein in the neural tissues of the brain and neurons get destroyed. The major symptoms are loss of memory, inability to recognize friends and relatives and inability to do routine works.

Parkinson’s:
Caused by the destruction of specialized ganglions in the brain due to reduced production ofdopamine, a neurotransmitter. The major symptoms are loss of body balance, irregular movement of musc les, shivering of the body and
profuse salivation.

Epilepsy:
Caused by continuous and irregular flow of electric charges in the brain. The
symptoms of epilepsy are due to continuous muscular contraction, frothy discharge from the mouth, clenching of the teeth following which the
patient falls unconscious.

Let Us Assess

Question 1.
The part of the brain which helps to maintain body balance.
a. Cerebrum
b. Cerebellum
c. Medulla oblongata
d. Thalamus
Answer:
b. Cerebellum

Question 2.
Identify the relation and fill in the blank.
Irregular flow of charge in the brain : Epilepsy Decreased production of dopamine : ………………….
Answer:
Parkinson’s

Question 3.
Analyze the following instances and answer the questions.

  • A thorn accidental ly pierces the foot
  • The leg is withdrawn
  • The thorn is taken out slowly

a. Write the stimuli and responses.
b. Which is the conscious response?
c. Was the leg withdrawn after sensing the pain? Which action took place there? Prepare an illustration showing the parts through which the impulses were transmitted.
Answer:
a. Stimuli -touch
Response – withdrawal of leg
b. The thorn is taken out slowly
c. No. Reflex action
Stimulus → receptor → sensoryneuron → intemeuron → motor neuron → related muscle → withdraws the leg.

Kerala Syllabus 10th Standard Biology Guide