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Kerala Syllabus Class 10 Biology Board Model Paper March 2024 with Answers English Medium
Time: 1½ Hours
Total Score: 40
Instructions:
- The first 15 minutes is cool-off time.
- You may use the time to read the questions and plan your answers.
- Answer only based on instructions and questions given.
- Consider score and time while answering.
Answer any 5 from questions 1-6. One score each. (5 × 1 = 1)
Question 1.
Identify the relationship in A and fill in B. (1)
(A) Dormancy of embryo: Abscisic acid
(B) Fruit formation: _________________
Answer:
(B) Fruit formation: Auxin
Question 2.
Which of the given statements is related to the sympathetic system? (1)
- Part of the autonomous nervous system.
- Part of the central nervous system.
- Production of saliva increases.
- Glycogen is converted to glucose.
Answer:
- Part of the autonomous nervous system.
- Glycogen is converted to glucose.
Question 3.
The hybridization of two contrasting traits of the character seed colour is illustrated below. Which will be the recessive trait of the F1 generation? (1)
Answer:
Green Seed Colour
Question 4.
What evidence supports the hypothesis given below? (1)
“Life originated in some other planet in the universe and accidentally reached the Earth.”
Answer:
The organic substances identified in the meteors that fell on Earth.
Question 5.
Choose the correct combination from the following: (1)
(i) Planaria: Eye spot: Taste
(ii) Shark: Jacobson’s organ: Smell
(iii) Snake: Lateral line: Body Balance
(iv) Housefly: Ommatidia: Light
(a) (i), (ii) correct.
(b) (ii) correct.
(c) (ii), (iii) correct.
(d) (iv) correct.
Answer:
(d) (iv) correct.
Question 6.
Correct the mistakes if any in the underlined part of the given statements.
(a) The complete genetic material present in an organism is called its genome.
(b) Gene mapping helps to identify the location of a particular gene in the DNA.
(c) The technology of testing the arrangement of nucleotides is gene therapy.
(d) Interferons are the proteins used for the treatment of viral diseases.
Answer:
(c) DNA Profiling (DNA Fingerprinting/DNA testing)
Answer any 6 from the questions 7-13. 2 scores each. (6 × 2 = 12)
Question 7.
Observe the illustration and answer the questions.
Organisms with variations
(a) Which theory of evolution is indicated here? (1)
(b) What is the significance of variations in the origin of new species according to this theory? (1)
Answer:
(a) Theory of Natural Selection (Darwin’s theory of evolution/Darwinism)
(b) Those with favorable variations survive in the struggle for existence. Variations that are inherited through generations and repeated differently, help to form species different from their ancestors.
Question 8.
Read the following statement and answer the question. (2)
‘The middle ear is separated from the external ear by the tympanum, air cannot pass through it’.
So how is the air pressure on either side of the tympanum regulated?
Answer:
The Eustachian tube helps to maintain a balance of air pressure on either side of the tympanum.
Question 9.
Observe the figures X and Y and answer the questions.
(a) Which neuron is present in abundance in the grey matter? What features did you consider for the selection? (1)
(b) In which neuron is the speed of impulse high? Why? (1)
Answer:
(a) Y, non-myelinated nerve cells are present in abundance is called grey matter.
(b) X, Myelinated axons transmit impulses much faster than other neurons.
Question 10.
Analyze the given condition and answer the questions:
‘Red blood cells bend like sickle’.
(a) Identify the disease. (1)
(b) In this condition, other blood cells do not undergo the same structural change as red blood cells. Why? (1)
Answer:
(a) Sickle cell anemia
(b) Because there is no hemoglobin in other blood cells. The defect in genes can cause deformities in the sequencing of amino acids, which are the building blocks of hemoglobin in Red blood cells.
Question 11.
Observe the illustration related to the sense of vision and answer the questions.
(a) Why is this type of image formed in the retina? (1)
(b) Even though such an image is formed, how can we see the object in its true form? (1)
Answer:
(a) Because the eye lens is a convex lens (Change in the curvature of the cornea and lens).
(b) The visual area of the brain (cerebrum) forms a correct image of the object. Then we can see the object in its true form.
Question 12.
Analyze the given illustration of the diseases and answer the questions.
(a) Complete ‘i’.
(b) Complete ‘ii’ and ‘iii’ choosing the appropriate one from the given diseases. (1)
Answer:
(a) (i) Viral Diseases
(b) (ii) Mosaic diseases
(iii) Hepatitis
Question 13.
Observe the poster against color discrimination and answer the questions.
(a) Name the pigment mentioned in the poster. (1)
(b) What is the reason for the rise and fall in the production of this pigment? (1)
Answer:
(a) Melanin
(b) Differences in the function of alleles of genes responsible for skin colour, is responsible for the rise and fall in the production of melanin.
Answer any 5 from questions 14-20. 3 scores each. (5 × 3 = 15)
Question 14.
Choose any one of the evidence given below and explain how it substantiates evolution.
(a) Palaeontology
(b) Physiology and Biochemistry
Answer:
(a) Primitive fossils have simple structures.
Recently formed fossils have complex structures.
Certain fossils are connecting links between different species.
Or
(b) Enzymes control chemical reactions
Energy is stored in ATP molecules.
Genes determine hereditary traits. / Carbohydrates, proteins, and fats are the basic substances.
All these give evidence that there was a common ancestor for all living organisms.
Question 15.
The opinions of three students on protein synthesis are given below. Analyze it and answer the question.
| Student 1 | Protein synthesis begins in the cytoplasm and ends in the nucleus. |
| Student 2 | Protein synthesis begins in the nucleus and ends in the cytoplasm. |
| Student 3 | The entire process of protein synthesis takes place in the nucleus. |
Whose opinion is correct? Explain why? (3)
Answer:
(a) Student 2
The types of protein to be produced are determined by the gene of DNA in the nucleus. DNA does not participate directly in protein synthesis. So, an mRNA is formed from the DNA inside the nucleus. The functional mRNA from the nucleus is then transported to the cytoplasm of the cell for protein synthesis. Ribosomes are the protein factories that are present in the cytoplasm of the cell along with the tRNA, which contributes to protein synthesis in the cytoplasm.
Question 16.
Prepare a flow chart related to the sense of taste by selecting the appropriate information given in the box. (3)
|
Answer:
Substances responsible for taste dissolve in the saliva → Enter in the taste bud → Stimulate the chemoreceptors → Generate impulses → Impulses reach cerebrum → Experience taste.
Question 17.
Some of the defense mechanisms in plants are given below: (3)
(a) Callose
(b) Cuticle
(c) Bark
How do each of them help in defense?
Answer:
(a) Callose prevents germs that have crossed the cell wall from entering the cell membrane.
(b) Cuticle prevent the entry of germs through leaves.
(c) Bark protects the inner cells from direct contact with pathogens.
Question 18.
Rearrange columns B and C by column A: (3)
| A. Disease | B. Pathogen | C. Spreading |
| Filariasis | Protozoa | Through Contact |
| Ringworm | Virus | Through Culex Mosquito |
| Malaria | Fungus | Through Air |
| Bacteria | Through Female Anopheles Mosquito |
Answer:
| A. Disease | B. Pathogen | C. Spreading |
| Filariasis | Filarial Worms | Through Culex Mosquito |
| Ringworm | Fungus | Through Contact |
| Malaria | Protozoa | Female Anopheles Mosquito |
Question 19.
Analyse the illustration and answer the questions:
(a) Which chemical is indicated as X?
(b) Fill in (i), (ii), (iii), and (iv).
Answer:
(a) X: Pheromones
(b) (i) Civetone
(ii) Muscone
(iii) Informing the availability of food
(iv) Determining the path of travel. (Any two)
Question 20.
Analyze 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. A plasmid with a ligated insulin gene is inserted into the bacterial cell.
- Step 4. Bacteria multiply in the culture medium.
(a) Which are the enzymes used in steps 1 and 2? (1)
(b) What is the role of plasmid in this process? (1)
(c) Whether the succeeding generations of this bacterium can produce insulin. Why? (1)
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 the bacterial gene.
They carry the gene responsible for insulin production in their DNA.
Answer any 2 from questions 21-23. 4 Scores each. (2 × 4 = 8)
Question 21.
Analyze the table and answer the questions:
| Person | Blood Group | Antigens | Antibodies |
| X | (i) _______ | B, D | (ii) _______ |
| Y | O-ve | (iii) _______ | (iv) _______ |
(a) Fill in (i), (ii), (iii), and (iv). (2)
(b) Can person Y receive blood from person X? Why? (2)
Answer:
(a) (i) B +ve
(ii) a
(iii) Nil
(iv) a, b
(b) No – Blood does to match B & D antigen in the donor (X) blood and the antibodies a and b in the recipient (Y) blood will react with each other. This results in the clotting of blood. So, that person Y, can not receive blood from person X.
Question 22.
Redraw the diagram. Identify and label the parts mentioned below.
Redraw the diagram.
(a) Part that controls involuntary actions. (1)
(b) Part that evokes sensations. (1)
(c) Part that receives impulses from the vestibular nerve. (1)
Answer:
(a) Medulla Oblongata
(b) Cerebrum
(c) Cerebellum
Question 23.
Observe the illustration showing hormone action in cells X and Y and answer the questions.
(a) Identify the target cell of the hormone indicated. Why? (1)
(b) How do hormones change cellular activities? (1)
(c) What is the role of the hypothalamus in regulating the production of hormones? (2)
Answer:
(a) X, The specific receptors of hormone present in X cell.
(b) The hormone molecules bind with the respective receptor to form a hormone-receptor complex on the target cell. Then, the enzymes in the cells are activated within them and create changes in cellular activities.
(c) The hypothalamus secretes both releasing hormones and inhibitory hormones.
The releasing hormones secreted by the hypothalamus stimulate the pituitary glands to produce tropic hormones, which in turn will stimulate the different endocrine glands to produce their corresponding hormones.
The hypothalamus produces inhibitory hormones which inhibit the secretions of tropic hormone by the combined action of these two hormones, most of the endocrine glands are properly regulated.