Plus Two Biology (Bot + Zoo) | Practice Model Question Paper PDF with Answer key | SET 10

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I. Answer any 3 questions from 1 – 5. Each carries 1 score. (3 x 1 = 3)

1) By observing the relationship of the first pair fill up the blanks:

GFC: Producers and consumers

DFC: Dead organic matter and ……………….

✅ Decomposers

2) The size of a population is not static. Which of the following leads to decrease in population?

a) Natality & Mortality

b) Mortality & Emigration

c) Mortality & Immigration

d) Natality & Immigration

✅ b) Mortality & Emigration

3) Development of fruit without fertilization and are seedless known as

a. Polyembryony          b. Apomixis

c. Parthenocarpy          d. Parthenogenesis

✅ c) Parthenocarpy

4) What is the function of Restriction Endonuclease in recombinant DNA technology?

a. Link together fragments of DNA

b. Make millions of copies of DNA

c. Cut DNA into many fragments

d. Separate fragments of DNA

✅ (c) Cut DNA into many fragments

5) Vitamin ‘A’ enriched rice is called ……………….

✅ Golden rice

II. Answer any 9 questions from 6 – 16. Each carries 2 scores. (9 x 2 = 18)

6) Distinguish between true fruit and false fruit with examples.


True fruits: In this, fruit develops only from the ovary. Other floral parts degenerate & fall off. E.g. most plants.

False fruits: In this, the thalamus also contributes to fruit formation. E.g. apple, strawberry, cashew etc.

7) A population has certain attributes that an individual organism does not. What are they?


Natality, mortality, sex ratio, age distribution, population density.
8) Parasites evolved special adaptations to live on host. What are they?


Parasitic adaptations:

▪️ High reproductive capacity.

▪️ Presence of suckers.

▪️ Digestive system absent.

9) A multinational company successfully cloned a gene of interest and also optimized the conditions to induce the expression of target protein.

a. Name the apparatus for large scale production of such proteins.

b. Briefly explain the apparatus.


(a) Bioreactors.

(b) These are the vessels in which raw materials are biologically converted to specific products, enzymes etc., using microbial, plant, animal or human cells. Bioreactors are used to produce large quantities of products. They can process 100-1000 litres of culture.

10) There are many features required to facilitate successful cloning into a vector. Write shortly any two such features required by a vector.


i. Origin of replication (ori): This is a sequence where replication starts. A piece of DNA linked to ori can replicate within the host cells. This also controls the copy number of linked DNA.

ii. Selectable marker (marker gene): It is a gene that helps to select the transformants and eliminate the non-transformants. If a piece of DNA is introduced in a host bacterium, it is called transformation. Selectable markers of E. coli include the genes encoding resistance to antibiotics like ampicillin, tetracycline, etc.

11) The early stages of embryo development are similar in both dicots and monocots. However, mature embryos have differences. Write two major differences between dicot embryo and monocot embryo.


Differences between dicot embryo and monocot embryo:
12) What is meant by insertional inactivation in biotechnology? Mention its importance.


When a foreign DNA is inserted within a gene of bacteria, that gene is inactivated. It is called insertional inactivation. E.g., the recombinant plasmids lose tetracycline resistance due to insertion of foreign DNA.

Importance: It allows for the selection of cells that have taken up the foreign DNA, distinguishing them from those that have only taken up empty plasmids.

13) A farmer approached an Agriculture officer to tell his grievance i.e., reduction in tobacco yield due to root damage by nematodes.

a. What is your suggestion to prevent this infestation?

b. Briefly explain the process.


(a) It can be prevented by RNA interference (RNAi) strategy.

(b) RNAi is a method of cellular defense in all eukaryotic organisms. It prevents translation of a specific mRNA (silencing) due to a complementary dsRNA molecule.

14) (a) Identify the type of ecological pyramid given below.

(b) Pyramid of energy is always upright. Why?


(a) Pyramid of biomass.

(b) Energy flows from a trophic level to next higher trophic level, only 10% of energy of a trophic level will be transferred to next higher trophic level.

15) Detritivores play a major role in decomposition.

a. What are detritivores?

b. Write an example for a detritivore.


(a) Detritivores are the organisms that breaks detritus to smaller particles.

(b) Earthworm, termites etc.

16) Analyse the following table showing population interaction:
a. Identify (i) and (ii).

b. Define (ii).


(a) i. 0          ii. Mutualism.

(b) Mutualism is the interaction that confers benefits for both interacting species.

III. Answer any 3 questions from 17 – 20. Each carries 3 scores. (3 x 3 = 9)

17) Bt cotton is a transgenic pest resistant plant.

a. How this was achieved?

b. How does this plant survive on pest attack?


(a) Bt toxin gene is isolated from Bacillus thuringiensis and incorporated into cotton plant to form Bt cotton.

(b) When an insect ingests the toxin in Bt cotton, it becomes active. Toxin binds to surface of mid-gut epithelial cells creating pores. It causes cell swelling and lysis and death of the insect.

18) Egg cell formation in angiosperms involves megasporogenesis and female gametophyte development.

a. Briefly write the various steps involved in female gametophyte development.

b. Mature angiosperm embryo sac at maturity is 8 nucleated but 7 celled. What is your explanation related to this statement?


(a) In majority of flowering plants, one megaspore is functional while the other three degenerates.

The functional megaspore develops into the female gametophyte.

Nucleus of the functional megaspore divides mitotically to form two nuclei. They move to the opposite poles, forming 2-nucleate embryo sac.

The nuclei again divide two times forming 4-nucleate and 8-nucleate stages of the embryo sac.

(b) 6 of the 8 nuclei are surrounded by cell walls and organized into cells. Remaining 2 nuclei (polar nuclei) are situated below the egg apparatus in the large central cell.

19) Observe the following diagram.
a. Identify the figure.

b. Label A, B and C.

c. Mention two types of restriction enzymes.


(a) Steps in formation of recombinant DNA by EcoRI.

(b) A= Vector DNA

B= EcoRI

C= Sticky end

(c) (i) Exonucleases: They remove nucleotides from the ends of the DNA.

     (ii) Endonucleases: They cut at specific positions within the DNA.

20) Decomposition is a process by which decomposers break down complex organic matter into inorganic substances like carbon dioxide, water and nutrients. Briefly explain the five steps of decomposition.


Steps of decomposition:

a. Fragmentation: It is the breakdown of detritus into smaller particles by detritivores (e.g. earthworm).

b. Leaching: Water soluble inorganic nutrients go down into soil horizon and precipitate as unavailable salts.

c. Catabolism: Degradation of detritus into simpler inorganic substances by bacterial and fungal enzymes.

d. Humification: Accumulation of humus (dark amorphous substance) in soil. Humus is resistant to microbial action and so decomposes very slowly. Being colloidal, it serves as a reservoir of nutrients.

e. Mineralization: It is the release of inorganic nutrients due to the degradation of humus by some microbes.


I. Answer any 3 questions from 1 – 5. Each carries 1 score. (3 x 1 = 3)

1) The family of Queen Victoria shows a number of haemophilic descendants as she was the carrier of the disease. Name the pattern of inheritance of this royal disease.

✅ Sex-linked (X-linked) recessive disease.

2) Identify the ancestor species of human being from the following features:

a. First human-like being (hominid). Brain capacity: 650-800 cc. Did not eat meat.

b. Large brain of 900 cc. Ate meat.

✅ (a) Homo habilis      (b) Homo erectus

3) Note the relation between first two terms and fill in the blanks.

a. Erythroxylum coca: Cocaine

Papaver somniferum: ……………….

b. Benign tumour: Do not spread

……………….: Spread to other parts

✅ (a) Opium          (b) Malignant tumour

4) The packaging of chromatin at higher level requires additional set of proteins called ……………….

✅ Non-histone Chromosomal (NHC) proteins.

5) Rearrange the following in correct sequence:

Mammary tubules → mammary alveoli → lactiferous duct → mammary ampulla → mammary duct

✅ Mammary alveoli → Mammary tubules → mammary duct → mammary ampulla → lactiferous duct

II. Answer any 9 questions from 6 – 16. Each carries 2 scores. (9 x 2 = 18)

6) Complete the table by filling a, b, c and d.


(a) Streptococcus pneumoniae

(b) Rhinovirus

(c) Malaria

(d) Deformity of limbs & genital organs

7) The list given below includes various stages of HIV infection. Arrange them according to correct sequence.

Viral replication – Macrophage - Helper T cell – Formation of DNA – Progeny virus – Viral particle – Release of progeny virus


Viral particle → Macrophage → Formation of DNA → Viral replication → Helper T cell → Progeny virus → Release of progeny virus
8) Observe the picture given below:
a. Identify the syndrome and write the genotype.

b. It occurs in both sexes (male and female). Write the reason.


(a) Down’s syndrome. Genotype is 45A+XX/XY

(b) Dwon’s syndrome is not a sex-linked disorder. It is the presence of an additional copy of chromosome number 21 (trisomy of 21). i.e., it is an autosomal problem.

9) Result of a famous experiment is given in the figure. Answer the questions.
a. Identify the experiment.

b. Which property of the DNA is proved by this experiment?


a. Meselson-Stahl experiment.

b. Semi-conservative model of DNA replication.

10) Given below is the diagrammatic representation of first stage of a process in bacteria.
a. Identify the process.

b. Name the enzyme which catalyzes this process.

c. What are the additional complexities in eukaryotes for this process?


(a) Transcription.

(b) DNA-dependent RNA polymerase

(c) (i) There are 3 types of RNA polymerases. (ii) The primary transcripts (hnRNA) should be processed to become functional mRNA.

11) (a) Define mutation.

    (b) What are the different types of mutation?


(a) Mutation the alteration of DNA sequences resulting in changes in the genotype and phenotype of an organism.

(b) Point mutation & Frame-shift mutation.

12) Observe the inheritance shown in A and B.
a. Name the type of the inheritance shown in A & B.

b. What is the difference between the two types of inheritance?


(a) A= Incomplete dominance

B= Codominance

(b) Incomplete Dominance is an inheritance in which heterozygous offspring shows intermediate character between two parental characteristics.

Codominance is the inheritance in which both alleles of a gene are expressed in a hybrid.

13) Amniocentesis for sex determination is banned in our country. Is this ban necessary? Comment on use of amniocentesis.


Yes. Because Amniocentesis is misused for sex determination. If the foetus is female, it is followed by MTP. This leads to male-female inequality and injustice to female.

Amniocentesis can be used legally to test the presence of genetic disorders, survivability of the foetus etc.

14) All copulations lead to fertilisation and pregnancy. Give reason.


Fertilisation can only occur if the ovum and sperms are transported simultaneously to the ampullary region.
15) Observe the diagram provided (Do not copy the picture).
a. Label A & B.

b. Write the name and function of the structure forming inside the ovary after the rupture of Graafian follicle.


(a) A= Primary follicle

B= Tertiary follicle.

(b) Corpus luteum. It secretes a hormone called progesterone which helps to maintain endometrium.

16) In our state, waste management is a problem. Government promotes and gives subsidy to Biogas plants. Comment the functioning of biogas plants with the help of microbes.


The cattle dung can be used for generation of biogas because it is rich in Methanobacterium.

The Biogas plant consists of a concrete tank to collect bio-wastes and slurry of dung. A floating cover is placed over the slurry, which keeps on rising as the biogas is produced. An outlet which is connected to a pipe to supply biogas. Another outlet is used to remove spent slurry.

III. Answer any 3 questions from 17 – 20. Each carries 3 scores. (3 x 3 = 9)

17) (a) Paternity or maternity can be determined by certain scientific methods. What is it? Define.

(b) Briefly explain the principles of this technique.

(c) Comment on its other applications.


(a) DNA fingerprinting. It is the technique to identify the similarities and differences of the DNA fragments of 2 individuals. Paternity or maternity can be determined by certain scientific methods.

(b) DNA fingerprinting is based on variable number tandem repeats (VNTR). It is specific from person to person.

(c) Other applications:

• Used to solve rape, murder etc.

• For the diagnosis of genetic diseases.

• To determine phylogenetic status of animals.

• To determine population and genetic diversities.

18) (a) What is ART?

(b) Diagnostic report of two couples having infertility problems are given below. Suggest a suitable Assisted Reproductive Technologies (ART) for each problem in expanded form.

i. The woman cannot produce ovum.

ii. The man has very low sperm count in semen.


(a) Assisted reproductive technologies (ART) are the technologies used to correct the infertility problems.

(b) i. Gamete Intra Fallopian Transfer (GIFT).

ii. The man has very low sperm count in semen. Artificial insemination (AI) / Intra-uterine insemination (IUI).

19) Four groups of organs are given below. Read them carefully and answer the questions:

i. Thorns of Bougainvillea and tendrils of Cucurbita

ii. Eyes of Octopus and mammals

iii. Flippers of Penguin and Dolphin

iv. Forelimbs of Cheetah and man

a. Categorise the four groups of organs as homologous organs and analogous organs.

b. Based on each group of organs differentiate convergent evolution and divergent evolution.


(a) Homologous organs: Thorns of Bougainvillea and tendrils of Cucurbita, Forelimbs of Cheetah and man.

    Analogous organs: Eyes of Octopus and mammals, Flippers of Penguin and Dolphin.

(b) Divergent evolution: It is the evolution by which related species become less similar to survive and adapt in different environmental condition.

     Convergent evolution: It is the evolution by which unrelated species become more similar to survive and adapt in similar environmental condition.

20) Two approaches of conservation of biodiversity are shown as A and B.
a. Identify the type of biodiversity conservation shown in A and B.

b. Write the difference between the two types of biodiversity conservation shown in A and B.

c. Which of the above approach is more desirable when there is an urgent need to save a species?


(a) A= In situ conservation B= Ex situ conservation.

(b) In situ conservation: It is the conservation of genetic resources within natural or human-made ecosystems in which they occur.

Ex situ conservation: It is the conservation of organisms outside their habitats.

(c) Ex situ conservation.

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