Madhyamik 2025 Life Science Question Paper | Madhyamik 2025 Life Science Question Paper
Section——A
(All questions must be answered)
1. Select the correct answer for each question and write it with its serial number. 1×15=15
1.1 Which of the following is not a structural feature of axon?
(a) Node of Ranvier
(b) Myelin sheath
(c) Nerve grana
(d) Swanson’s corpuscle
1.2 Which of the following is the function of ADH hormone?
(a) It constricts the arteries and increases blood pressure
(b) It helps in the production of sperm and eggs in adulthood
(c) It converts glucose into glycogen and stores it in the liver and muscles
(d) It develops the nervous system and maintains normal function
1.3 Cornea, choroid, lens, aqueous humor, iris, vitreous humor—how many of these parts of the eyeball are the refractive medium of the eyeball?
(a) 3 (b) 4 (c) 5 (d) 6
1.4 Which of the following is correct regarding the chemical composition of nucleotides?
(a) 5-C sugar + phosphoric acid = nucleotide
(b) N2-containing base + phosphoric acid = nucleotide
(c) 5-C sugar + N2-containing base = nucleotide
(d) 5–C sugar + N2-containing base + phosphoric acid = nucleotide
1.5 Which of the following pairs is correct regarding the method of cross-pollination?
Plant name
(a) Wind-pollinated mango
(b) Water-pollinated rice
(c) Moth-pollinated hydrilla
(d) Bird-pollinated palash
1.6 Which of the following stages of ferns does not belong to the genus Renudhara?
(a) Prothallus (c) Germ cell (b) Sorus (d) Germ cell
1.7 In the case of guinea pigs, what is the ratio of the number of BbRr and BBRR genotypes produced in the F2 generation of a dihybrid cross?
(a) 2 : 1
(b) 4:1
(c) 1:2
(d) 1:1
1.8 Which two genotypes below exhibit the genotype of pea plants with yellow colored and wrinkled shaped seeds?
(ক) YYrr, Yyrr
(গ) yyRR, yyRr
(খ) YYRr, YyRR
(ঘ) YYRR, yyrr
1.9 In case of incomplete dominance, what is the genotype and phenotype ratio in the F2 generation of a crossbreed?
(a) 2 : 1:1
(c) 1:2:1
(b) 1:1:1
(d) 1 : 2:2
1.10. Which of the following is not a statement of Darwin’s theory?
(a) Inheritance of acquired characteristics
(b) Struggle for survival
(c) Variation
(d) Natural selection
1.11. Identify the characteristics of homologous parts—
(a) Structurally different but identical in origin and function
(b) Structurally identical but different in origin and function (
c) Structurally and functionally identical but different in origin
(d) Functionally identical but different in origin and structure
1.12. What are the reagents used in Miller and Urr’s experiment on the chemical origin of life?
(a) Oxygen, methane, nitrogen dioxide
(b) Water, methane, ammonia, hydrogen
(c) Methane, hydrogen sulfide, carbon monoxide
(d) Nitrous oxide, methane, carbon dioxide
1.13. Identify the correct sequence of the nitrogen cycle—
(a) Nitrogen fixation → denitrification → ammonification → nitrification (b)
ammonification nitrification →
nitrogen fixation → denitrification (c) nitrogen fixation → ammonification → nitrification → denitrification
(d) nitrification → nitrogen fixation → denitrification → ammonification
1.14. Which of the following pairs of causes of decline and affected species is correct in terms of biodiversity loss?
(a) Invasion of exotic species – One-horned rhinoceros
(b) Pollution – Royal Bengal tiger
(c) Global warming and climate change – Polar bear
(d) Hunting and poaching – Vulture
1.15. Which of the following occurs when a chlorinated pesticide enters a food chain?
(a) Biodiversity
(c) Global warming
(b) Eutrophication
(d) Deafness
Category-‘B’
2. Write the answers to 21 of the 26 questions below as instructed: 1×21=21
Fill in the blanks in the sentences below with the appropriate words (any five).
2.1 Nastic movement is influenced and controlled by the _________ of external stimuli.
2.2. ____________- Meiosis keeps the chromosome number of a species constant.
2.3 The bulging shape of the seed is a __________ characteristic. 2.4 The shape of the RBC of the camel’s blood is _________, which allows it to tolerate high levels of water loss.
2.5 A disease associated with air pollution is____________
2.6 Both Nilgiris and __________ are biosphere reserves.
Determine whether the following sentences are true or false. (Any five) 1×5=5
2.7 Auxin hormone inhibits the growth of primary buds and promotes the growth of axillary buds.
2.8. If the checkpoints are disrupted, cell division becomes uncontrolled.
Only one type of gamete is produced from a pea plant with the genotype 2.9 YyRR.
2.10 Intraspecific and interspecific conflict may be observed between different types of tigers in a forest.
2.11. Nitrous oxide is a greenhouse gas.
2.12. The triceps is a flexor muscle.
Rewrite the correct pair (any five) by matching the word given in column ‘A’ with the most appropriate word given in column ‘B’, mentioning the serial number of both columns:
‘A’ pillar ‘B’ pillar
2.13 Meninges
2.14 Sexual reproduction
2.15 Roller tongue
2.16 Evolution of horses
2.17 Environmental problems of the Sundarbans
2.18 Connecting chromosomes to the Bemantantu
(a) Reduction in the number of toes
(b) Subsidence of islands
(c) Centromere
(d) Telomere
(e) Protects the brain and spinal cord from mechanical injury
(f) Controlled by autosomes
(g) Occurs through gamete production and fusion of gametes
Answer in one word or one sentence (any six)
2.19 Choose the opposite word—testosterone, insulin, progesterone, estrogen.
2.20 What is the relationship between lenses and eye adaptation?
2.21 Understand the relationship between the first pair of words below and fill in the blanks of the second pair with the appropriate word:
Mitosis : meiosis :: —: reduction division
2.22 What can a being be pure for one character but different for another?
2.23 Write a characteristic of the gene responsible for color blindness.
2.24 What theory can be reached from a comparative discussion of the embryos of different vertebrates?
2.25 Out of the four topics below, any three belong to another topic. Find that topic and write it down – Decline of agricultural land, shortage of fresh water, problem of increasing population, destruction of forests.
2.26 Write one characteristic of a biodiversity hotspot.
Category –’C’
3. Write the answer to any 12 of the 17 questions below in two or three sentences. 2×12=24
3.1. The sneezing and coughing reflex helps to avoid two dangers—judge the accuracy of the statement.
3.2. How does the gibberellin hormone cause seed germination and increase plant height?
3.3. Write one effect each of thyroxine hormone on heart and red blood cells.
3.4. Explain the following two terms-Ganglia, Synapse
3.5 Write two characteristics of amitosis cell division.
3.6 Mention two events in the G phase of interphase.
3.7 Explain the process of fragmentation with the help of a suitable example from a plant.
3.8 What is the importance of genetic counseling in establishing a marriage relationship?
3.9 Write two reasons for Mendel’s selection of pea plants for genetic experiments. If the father is color blind and the mother is completely normal, write down the probability of what percentage of their children being color blind.
3.10. An inherent characteristic of living things is to reproduce at a high rate; as a result, the number of living things increases geometrically—prove the correctness of the statement with the help of two examples.
3.11 When worker bees find a food source, how do they communicate that message to other worker bees in the hive?
3.12 What is meant by natural selection?
3.13 One problem of increasing population is the destruction of wetlands – mention two things that can happen as a result.
3.14 Invasion of exotic species leads to loss of biodiversity – prove the correctness of this statement in the case of India with two examples.
3.15. Name one endangered plant and one endangered mammal of the Eastern Himalayan hotspot.
3.16. Write one role each of Joint Forest Management (JFM) and People’s Biodiversity Register (PBR) in biodiversity conservation.
Category—’D’
(Long answer questions)
4. Write answers to the six questions below or their alternatives. Visually impaired candidates will have to answer question 4.1(A) instead of question 4.1. Each question carries 5 marks (the question mark division can be 3+2, 2+3 or 5).
4.1. Draw a scientific diagram of the cross-section of the human eyeball and identify the following parts—(a) Choroid (b) Lens (c) Cornea or (d) Vitreous humor 3+2=5
4.2. Draw a scientific diagram of the anaphase stage of mitosis of animal cells and identify the following parts—(a) Centromere (b) Daughter chromosome (c) Polar region (d) Mathematical theorem 3+2=5 (Only for visually impaired candidates)
4.1 (A) Write one function of each of the following five parts of the human eyeball: (a) Cornea (b) Lens (c) Choroid (d) Vitreous humor (e) Retina Or Mention three changes that occur during the anaphase stage of mitosis of animal cells. Write the name of any two structural parts of eukaryotic chromosomes.
4.2. Explain the following three meanings of the division of the kosh-bi-shava:
Growth, repair
• Write the places where meiosis cell division occurs in the biological world with the help of a table.
Or
• Explain the method of micropropagation.
• Distinguish between asexual and sexual reproduction in the following three ways: – Cell division of reproductive organisms
• Origin of variation 2+3=5
4.3 If a pure black and rough-haired guinea pig is crossed with a pure white and smooth-haired guinea pig, show the phenotype ratio of the offspring produced in the second generation using a checkerboard. “The father plays a major role in determining the sex of the offspring” – verify the truth of the statement using a checkerboard. 3+2=5
Or
Write three reasons for Mendel’s success. Establish the relationship between phenotype and genotype with suitable examples. 3+2=5
4.4. Explain Darwin’s theory of the giraffe’s neck becoming longer. What is ‘hot dilute soup’? Or construct a sequence of major events in biological evolution with the help of a diagram. Give two examples of the problem-solving skills of chimpanzees.
4.5. Write one symptom each of two diseases that can be caused when floating particles enter the respiratory tract through inhalation. Create a sequence of events that occur when agricultural waste mixes with water bodies. OR One of the main reasons for the decline in biodiversity is poaching – as a result, make a list of any three wild animals that are on the verge of extinction today. Show the methods of conservation of biodiversity with the help of a table.
4.6. The three environmental problems of the Sundarbans are: • Disruption of the balance between food and prey • Destruction of salt marsh plants due to urbanization • Rising sea levels. Analyze the possible consequences of the three problems. Write the location of a biodiversity hotspot that extends over a geographical area in India and outside India and the name of an endangered species in that hotspot. Or describe the nitrogen cycle through a word picture. Analyze two problems that can arise if the nitrogen cycle is disrupted.
Section ‘E’
(For external candidates only)
5. Answer any 4 questions: 1X4=4
5.1 Write one feature of the endosperm.
5.2 What is the function of ribosomes?
5.3 Write one function of the parenchyma.
5.4. Write one advantage of self-pollination.
5.5 Give an example of a protein digesting enzyme.
6. Answer any three questions: 2×3=6
6.1 Write two differences between axon and dendron.
6.2. Write the names of two nitrogenous waste products of plants. 6.3 Write one function each of mitochondria and centrosome. Write the names of two sanctuaries of West Bengal.
6.4. Write the names of two sanctuaries of West Bengal.