Madhyamik 2025 Life Science Question Paper | Madhyamik 2025 Life Science Question Paper

Category- A

1) Complete the sentence by choosing the correct answer to each question and writing its serial number: 1 x 15= 15

(i) Some flowers bloom after sunrise, but wither with sunset. This is – 

(a) Photonasty,
(b) Seismonasty,
(c) Chemonasty,
(d) Thermonasty.

(ii) A person suffering from diabetes mellitus is unable to secrete which of the following hormones in sufficient quantity? –

(a) adrenaline,
(b) insulin,
(c) thyroxine,
(d) testosterone.

(iii) The part of the human brain associated with the control of ‘physical arousal’ is –

(a) Thalamus,
(b) Cerebellum,
(c) Hypothalamus,
(d) Spinal cord.

(iv) You see the separation of sister chromatids during a stage of mitosis cell division. The stage is –

(a) Prophase,
(b) Telophase,
(c) Anaphase,
(d) Metaphase.

(v) Which of the following pairs is correct? –

(a) Corygome – Yeast,
(b) Fragmentation – Earthworm,
(c) Molecular production – Amoeba,
(d) Reproduction – Dryopteris.

(vi) The perfection of the genitals and gonads occurs at the time of human maturation —

(a) In childhood,
(b) In adolescence,
(c) In old age,
(d) In the newborn period.

(vii) The latent characteristic of the pea plant is –

(a) Conical seeds,
(b) yellow seeds,
(c) purple flowers,
(d) axillary flowers.

(viii) How many types of gametes are produced from a pea plant with the genotype YyRr? –

(a) 1,
(b) 4,
(c) 2,
(d) 3।

(ix) The probability of daughters of a hemophilia carrier mother and a normal father being affected by hemophilia is –

(a) 75%,
(b) 50%,
(c) 100%,
(d) 0%।

(x) The gas that was absent in the atmosphere at the time of the creation of life on Earth is –

(a) Hydrogen,
(b) Oxygen,
(c) Methane,
(d) Ammonia.

(xi) The characteristic of symmetrical organs is –

(a) Different in origin and different in function,
(b) Different in origin but same in function,
(c) Indicates divergent evolution
(d) Same in origin and structure.

(xii) Which of the following absorbs gas from the bony fish’s gills? –

(a) Red gland,
(b) Anterior chamber,
(c) Gastric gland,
(d) Retia mirabilia.

(xiii) The bacterium Pseudomonas is associated with which of the given steps of the nitrogen cycle?

(a) Nitrogen fixation,
(b) Nitrification,
(c) Denitrification,
(d) Ammonification

(xiv) An endangered species of the East-Himalayan Biodiversity Hotspot is –

(a) Lion-tailed macaque,
(b) Orangutan,
(c) Red panda,
(d) Nilgiri tiger.

(xv) Diseases associated with air pollution are –

(a) Diarrhea, typhoid, hepatitis,
(b) Hepatitis, bronchitis, deafness,
(c) Bronchitis, asthma, lung cancer,
(d) Lung cancer, polio, malaria.

Section- B

2) Write the answers to any 21 of the 26 questions below as instructed: 1×21=21

Fill in the blanks in the following sentences by inserting suitable words: (Any five) 1×5=5

(i) The method of adjusting the focal length of the lens of the human eye as required is called ___.

(ii) Adenine is a _______ type of nitrogenous base.

(iii) ______ is a disease caused by a sex-linked gene.

(iv) The earliest ancestor in the evolution of horses is_____

(v) A flammable greenhouse gas produced from rice fields is______.

(vi) _____ is a biosphere reserve located in West Bengal.

Determine whether the following sentences are true or false: (Any five) 1×5=5

(vii) Gibberellin hormone prevents premature defoliation of plants.

(viii) Eggs are produced only by mitosis.

(ix) Pea flowers can be self-pollinated or cross-pollinated as required.

(x) The process of natural selection is the main theme of Darwin’s theory of evolution.

(xi) Fragile contaminants are responsible for biodegradation.

(xii) Flagella are the locomotor organs of paramecium.

Rewrite the correct pair of comic numbers in both columns by matching the word given in column A with the most appropriate word given in column B: (Any five) 1×5=5

A level B level

(xiii) Blind spot (a) Groundwater pollution
(xiv) Cytokinesis (b) Retina and optic nerve junction
(xv) 44A + XY (c) Homologous organs
(xvi) Wings of bats and birds (d) Structure of the oviduct
(xvii) Arsenic (e) Pollen
(xviii) Migration to the cervix (f) Noise pollution
(g) Chromosome arrangement of male humans

Answer in one word or one sentence (any six) 1×6=6

(xix) Choose the opposite and write – TSH, ACTH, GTH, CSF

(xx) Write a work on myelin sheath.

(xx) A related pair of words is given below. Understand the relationship of the first pair and fill in the blanks of the second pair with the appropriate word – Prophase: Disappearance of the nuclear membrane and nucleolus :: Reappearance of the nuclear membrane and nucleolus.

(xxi) Give an example of a variation transmitted through heredity in humans.

(xxiii) Which type of chromosome in humans carries the gene responsible for thalassemia disease?

(xxiv) Mention a morphological adaptation of cactus to prevent transpiration.

(xxv) Out of the four given topics, three belong to one topic, find out that topic and write it: soil, dividing banana, seeds, cryopreservation.

(xxvi) Name the reason for the recent environmental concern in the Sundarbans.

Section-C

3) Write the answer to any 12 of the 17 questions below in two-three sentences: 2 x 12= 24

(i) Write two differences between tropic movement and nastic movement.

(i) Write two roles of GTH in the secretion of hormones from the gonads in the human body.

(ii) List which of the following actions are innate or acquired reflex actions.

(a) The desire of a newborn to suckle;
(b) Riding a bicycle;
(c) Sneezing;
(d) Catching the wicket-keeper’s ball with agility.

(iv) Write the parts of the central nervous system and the peripheral nervous system.

(v) Write two important points of the cell cycle.

(vi) Determine the difference between DNA and RNA based on the given characteristics:

(a) Pyrimidine bases;
(b) 5-C sugars.

(vii) Which vectors carry out pollination in the given plants?

(a) Paddy;
(b) Leafy greens;
(c) Shimul;
(d) Mango.

(viii) Write with the help of examples how the dominant trait is revealed in the hybridization experiment.

(ix) In case of incomplete dominance, what will be the ratio of phenotype to genotype in the F-gene in a cross experiment?

(x) Show with the help of a cross how colour blindness is inherited.

(xi) Write the name of the reactants used in Miller and Urey’s experiment on the chemical origin of life and one organic compound produced.

(xii) Write four important characteristics that have changed in the evolution of horses.

(xiii) How does the Sundari tree excrete excess salt from its body?

(xiv) Write the names of two microorganisms that participate in the biological nitrogen fixation process.

(xv) Mention two damages caused by acid rain.

(xvi) Give four examples of the loss of biodiversity caused by the development of the world.

(xvii) Write the main issues related to biodiversity recorded in the People’s Biodiversity Register (PBR).

Section-1

4) Write the answers to the following six questions or their alternative questions: 5×6=3 0

(i) Draw a neat diagram of the cross-section of the human eyeball and label the following parts. (a) Cornea, (b) Lens, (c) Vitreous humor, (d) Retina. 3+2=5

Or,

Draw a neat picture of the metaphase stage of mitosis cell division of a plant cell or an animal cell and label the given parts: (a) chromosomes, (b) spindle, (c) polar regions, (d) centromere. 3+2=5

(ii) Explain the interrelationship between chromosomes, DNA and genes. Write the difference between euchromatin and heterochromatin on the following two points: (a) Coiling; (b) Activity.3+2=5.

Or,

How is micropropagation carried out? Explain the following three stages of sexual reproduction in flowering plants: (a) Gamete production; (b) Fertilization; (c) Embryo formation and formation of new plants. 2+3=5

(iii) Show with the help of a checker board the types of offspring that can be produced by mating a hybrid black guinea pig with a pure white guinea pig. State Mendel’s law of segregation. 3+2=5

Or,

Mention the symptoms of thalassemia. In many families, the mother is blamed for the birth of a girl child. Show with the help of a cross that this idea is not correct. 2+3=5

(iv) Mention the two structural features on the basis of which the ‘whale flipper’ and the ‘bird wing’ are considered as homologous organs. How does a worker bee in a hive find and inform other worker bees about the location of food sources? 2+3=5

Or,

Show the main events of expression or evolution through a time series diagram.

(iv) What are the causes of asthma? What is the role of Joint Forest Management in biodiversity conservation? 2+3=5

Or,

Determine the reasons for the decline in biodiversity with the help of correct examples.

(vi) Suggest two conservation measures to increase the population of Indian one-horned rhinoceros. Give your opinion on the ways in which freshwater sources are polluted – based on your experience. 2+3=5

Or,

What conditions would you consider if you wanted to declare one of the two areas as a biodiversity hotspot? Give two examples of ex situ conservation. 3+2=5