Reviewing solved Biology Class 10 Kerala Syllabus Question Paper Set 3 English Medium helps in understanding answer patterns.
Biology Class 10 Kerala Syllabus Model Question Paper Set 3
Time: 1 1/2 hours
Total Score: 40
Instructions:
- The first 15 minutes is cool-off time.
- This time can be used for reading the questions and planning the answers
- Write answers only according to the instructions and questions
- While writing the answers, consider the score and time.
Questions from 1 to 4 carry 1 score each. (4 × 1 = 4 scores)
Question 1.
Select the correct answer
Statement 1 : A dominant allele cannot fully hide the allele of the recessive trait in Co-dominance Statement 2 : Difference in skin colour is due to Multiple allelism.
(A) Statement 1 and statement 2 are correct
(B) Statement 1 and statement 2 are wrong
(C) Statement 1 wrong statement 2 correct
(D) Statement 1 correct statement 2 wrong
Answer:
(D) Statement 1 correct statement 2 wrong
Question 2.
Examine the statement and reason and select the correct answer.
Statement: The intensity of sound decreases ten¬fold for every 10 decibels.
Reason: For every 10 decibels, the intensity of sound increases tenfold.
(A) Both the statement and the reason are correct. The reason is the correct explanation of the statement.
(B) Both the statement and the reason are correct. The reason is the wrong explanation of the state¬ment.
(C) Statement is correct. Reason is wrong.
(D) Statement is wrong. Reason is correct.
Answer:
(D) Statement is wrong. Reason is correct.
Question 3.
Which of the following statements regarding junk genes is correct?
a) All genes in human DNA help in making proteins.
b) Genes that help in making proteins are called junk genes.
c) Junk genes have no function.
d) Junk genes are non-functional DNA segments.
Answer:
d) Junk genes are non-functional DNA segments.
Question 4.
Which of the following statements about rod cells are correct?
i) Rod cells are responsible for vision in dim light.
ii) Rod cells contain the visualpigment called rhodopsin.
iii) Rod cells help in detecting different colours.
iv) Rod cells are fewer than cone cells.
v) Rod cells are cone shaped.
(a) i, ii, iii correct
(b) i, ii correct
(c) ii, iii, v correct
(d) iii, iv, v correct
Answer:
(b) i, ii correct
Questions from 5 to 11 carry 2 scores each. (7 × 2 = 14 scores)
Question 5.
A. Redraw the given diagram and answer the fol-lowing questions:
(a) Identify a, b and c in the given diagram.
(b) What is the function of myelin sheath?
Answer:
(a) a – Synaptic knob, b – Axon, c – Dendron.
(b) The functions of myelin sheath are to increase the speed of transmission of messages, by acting as an insulator, to provide nourishment to the neuron and to protect the axon from external injuries.
OR
B. Ependymal cell, Oligodenrocyte, Microglial cell, Schwann cell, Astrocyte
(a) What are these cells called?
(b) What is the function of ependymal cells?
Answer:
(a) Neuroglial cells
(b) Ependymal cells play a role in the formation of cerebrospinal fluid.
Question 6.
Observe the picture and answer the questions given below.
(a) Identify the part indicated as X?
(b) How Action potential in neuron is formed?
Answer:
(a) Receptor potential in the recepters of the skin
(b) Electrical impulses are produced in receptors in response to external and internal stimuli. These 9. impulses are known as receptor potential. When such impulses are in higher concentration, action potential is formed in the neurons associated with receptors.
Question 7.
The illustration given below indicates the transmis-sion of impulses from one neuron to another. Observe the illustration and answer the following question.
(a) Identify the part in the illustration.
(b) Identify the chemical substance which is secreted from A. Give one example for this chemical substance.
Answer:
(a) Synapse
(b) Neurotransmitters. Acetylcholine/dopamine/ serotonin/endorphin
Question 8.
A. The hybridisation experiment conducted by Mendel considering the trait of the height is depicted in the illustration. Observe the illustration and answer the questions given below.
(a) Write the genotype of the first generation and the parental tall plant.
(b) If the first-generation plants are self-pollinated, what are the possible phenotypes of the plants obtained in the second generation, and in what ratio?
Answer:
(a) Parental tall plant-TT First geenration tall plant- Tt
(b) Tall and Dwarf in 3 : 1 generation
OR
B. Observe the illustration and answer the questions given below.
(a) Illustrate the cross between first generation and the parental tall plant.
Answer:
Question 9.
Balu: In the spinal cord and the cerebrum, white matter is seen outside, and grey matter is seen in¬side.
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) In the brain and the spinal cord, the part where myelinated heurons with are more abundant is called the white matter and the part where the cell bodies and parts of the neurons without a myelin sheath are seen is called the grey matter.
Question 10.
Complete the following illustration:
Answer:
A – Central canal,
B – Sensory impulses,
C – Ventral root
Question 11.
The details of blood groups of two persons are given in the table. Analyse them and answer the questions.
| Person | Antigen | Antibody | Rh factor |
| X | B | a | Present |
| Y | A | b | Absent |
a) Identify the blood groups of persons X and Y.
b) Can Y receive blood from X? Why?
Answer:
a) X-B Group, Y- A Group
b) No, the antigen in the donor’s blood will react with the antibody in the recipient’s blood and cause the blood to clot.
Questions from 12 to 17 carry 3 scores each. (6 × 3 = 18 scores)
Question 12.
Even using permanent mosquito repellents, mosquitoes cannot be completely destroyed. Write a scien-tific explanation for this statement based on the theory of evolution.
Answer:
Some mosquitoes develop resistance to insecticides. This is survival of the fittest. Those that are resistant to insecticides survive and the others die.
Question 13.
A. Given below is the portion of a poster.
Don’t take high eye pressure easy.
It may lead to blindness in future.
a) Which is the eye disease mentioned in the poster?
b) What is the reason for this condition?
c) What is the remedy for this disease?
Answer:
a) Glaucoma
b) • Blockage of reabsorption of aqueous humour
• Increase in the pressure inside the eyes
c) Laser surgery
OR
B. Redraw the diagram given below. Identify the parts and label it.
Answer:
a) Eustachian tube
b) Cochlea
c) Tympanum
Question 14.
What is the normal level of calcium in the blood? How is this level maintained?
Answer:
9-11 mg/100 ml blood. When the level of calcium in blood increases, thyroid gland secretes a hormone named calcitonin. It lowers the level of calcium in blood by depositing excess calcium in bones and by preventing the mixing of calcium with blood form the bones. When the level of calcium in blood decreases, parathyroid gland secretes parathormone. It increases blood calcium by reabsorbing it from the kidneys and also preventing the deposition of calcium in bones.
Question 15.
A. Observe the illustration of bacteria and answer the questions.
a) Which part is denoted as ‘X’?
b) What is the significance of ‘X’ in the process of genetic engineering?
Answer:
a) X: Plasmid/Circular DNA of bacteria
b) • Plasmids are used to transfer a gene from one cell to another as vectors
• Vectors that contain ligated genes enter target cells, and the new genes become a part of the genetic constitution of target cells
OR
B. Analyse the steps in the production of human insulin through genetic engineering and answer the questions.
Step 1. Cutting of insulin gene from human DNA
Step 2. Joining insulin gene with plasmid
Step 3. Plasmid with ligated insulin gene is inserted into bacterial cell
Step 4. Bacteria multiply in the culture medium
a) Which are the enzymes used in step 1 and 2.
b) What is the role of plasmid in this process?
c) Whether the succeeding generations of this bacterium have the ability to produce insulin. Why?
Answer:
a) Step 1: Restriction endonuclease (Genetic scissors) Step 2: Ligase (Genetic glue)
b) A gene from one cell is transferred to another cell
c) Yes. The human insulin gene becomes part of a part of the genetic constitution of target cells.
Question 16.
Observe the illustration and answer the questions given below.
(a) Identify the illustration.
(b) Identify the stages indicated as (i), (ii).
(c) Identify the parts indicated as A,B.
Answer:
a) Protein synthesis
b) (i) Transcription (ii) Translation
c) A – Amino acid B – Ribosome
Question 17.
Complete the table.
| Plant Hormone | Function |
| Synthetic Auxins | __(A)__ |
| __(B)__ | Used to increase fruit size in grapevines and for stem elongation in sugarcane. |
| Synthetic Ethylene | __(C)__ |
Answer:
a) Used to induce root formation in stem cuttings. Also used as a weedicide (2,4-D)
b) Synthetic gibberellins
c) In agricultural sector, ethylene is used to make fruits ripen uniformly for harvest at the same time. Ethylene is used to ripen bananas and to-matoes simultaneously.
The 18,h question carries 4 scores (1 × 4 = 4 scores)
Question 18.
A. The symptoms of a disease is given below.
The main symptoms are a persistent cough for more than two weeks, fever, loss of appetite, weight loss, and fatigue. Sometimes blood may be seen in the sputum.
(a) Identify the disease.
(b) Name the pathogen.
(c) Waht are the part of the body affected by this disease?
(d) What is the Prevention, treatment of this disease?
Answer:
a) Tuberculosis
b) Mycobacterium tuberculosis
c) Although it mainly affects the lungs, it can also affect other parts of the body, such as the kid-neys, bones, and the brain
d) BCG vaccination. Long-term treatment by us¬ing multiple antibiotics (DOTS) simultaneously
OR
B. The name of a pathogen is given below. Human Immunodeficiency Virus
(a) Identify the disease caused by this pathogen.
(b) How the patogen affets our body?
(c) What is the mode of transmission of this disease?
Answer:
a) AIDS
b) Tlymphocytes. The virus attacks, and destroys them by multiplying using the genetic mecha-nism of Tlymphocytes. As a result, the body’s ability to fight diseases is reduced and gradu¬ally the condition reaches to AIDS.
c) HIV can be transmitted through sexual contact with an infected person, by sharing needles and syringes that are not HIV-free, through transfusion of blood or organs containing HIV, and from an infected mother to the foetus.