Plus Two Biology (Bot + Zoo) | Practice Model Question Paper PDF with Answer key | SET 8

Example Webpage

👉 Download Biology Question Paper PDF - SET 8


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

1) Some type of Orchids lives on the branches of mango trees. The relationship between mango tree and Orchid is an example of

a) Mutualism              b) Predation

c) Commensalism        d) Parasitism

✅ c) Commensalism

2) In flowering plants, double fertilization occurs during reproduction. One of the events of double fertilization is triple fusion. Name the other event.

✅ Syngamy

3) Identify palindrome sequence from the following.

a) 5’- GAATTC -3’
    3’- CTTAAG -5’

b) 5’- ATCG -3’
    3’- TAGC -5’

c) 5’- AAAAA -3’
    3’- TTTTTT -5’

d) 5’- CCCCC -3’
   3’- GGGGG -5’

✅ a) 5’- GAATTC -3’
          3’- CTTAAG -5’

4) Which of the following is a detritivore?

a) Earthworm        b) Virus

c) Fox                    d) Cow

✅ a) Earthworm

5) Biotechnology in agriculture leads to pest resistant plants, which could decrease the amount of pesticides used. For example, Bt cotton. Expand the letters ‘B‘ and ‘t’.

✅ B= Bacillus     t= thuringiensis

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

6) Given diagram shows an important process in biotechnology.
a. Identify the process.

b. Some of the events of this process are given below. Arrange them in correct order:

i. Cut out DNA bands

ii. Expose to UV

iii. Force DNA to move through gel

iv. Stain DNA with ethidium bromide


(a) Gel electrophoresis.

(b) iii. Force DNA to move through gel → iv. Stain DNA with ethidium bromide → ii. Expose to UV → Cut out DNA bands

7) Explain the equation GPP – R = NPP.


Gross primary productivity (GPP): It is the rate of production of organic matter during photosynthesis. A considerable amount of GPP is used by plants in respiration.

Net primary productivity (NPP): It is the available biomass for the consumption to heterotrophs (herbivores & decomposers). i.e., NPP is the Gross primary productivity minus respiration losses (R).

8) A diagram of LS of a flower showing growth of pollen tube is given below. Label A to D.


A= Antipodal        B= Polar nuclei

C= Egg cell        D= Synergid

9) Match the column A with column B:


10) Among many, there are two core techniques that enabled birth of modern biotechnology. Name and briefly explain them.


Two core techniques that enabled birth of modern biotechnology:

a. Genetic engineering: The technique in which genetic material (DNA & RNA) is chemically altered and introduced into host organisms to change the phenotype.

b. Bioprocess engineering: Maintenance of sterile ambience in chemical engineering processes for growing desired microbe/eukaryotic cell for the manufacture of antibiotics, vaccines, enzymes etc.

11) Flowers are classified into Chasmogamous and Cleistogamous flowers.

a. Cleistogamous flowers are autogamous. Justify.

b. Define autogamy.


(a) Anthers and stigma lie close to each other. They are not exposed.

(b) It is the transfer of pollen grains from the anther to the stigma of the same flower.

12) What is meant by Resource partitioning? Explain with an example.


Resource partitioning is the division of limited resources by species to avoid competition. For this, they choose different feeding times or different foraging patterns.

E.g. MacArthur showed that five closely related species of warblers living on a tree could avoid competition and co-exist due to behavioural differences in their foraging activities.

13) A given species may occupy more than one trophic level in the same ecosystem at the same time. Justify this statement with suitable example.


This statement is true.

For example, a sparrow is a primary consumer when it eats seeds, fruits, peas, and a secondary consumer when it eats insects and worms.

14) Prey species have evolved a variety of defense mechanisms to lessen the impact of predation. Mention any four of them.


Defenses of prey species to lessen impact of predation:

• Camouflage (cryptic colouration) of some insects & frogs.

• Some are poisonous and so avoided by the predators.

• Monarch butterfly is highly distasteful to its predator bird. It is due to a special chemical in its body. It is acquired during its caterpillar stage by feeding on a poisonous weed.

• Thorns (Acacia, Cactus etc.) are the most common morphological means of defense of plants.

15) Analyze the following diagram showing the representation of age pyramids for human population. All items are mislabeled. Correct them.


(x) Post-reproductive

(y) Reproductive

(z) Pre-reproductive

(a) Expanding (growing)

(b) Stable

(c) Declining

16) Expand short forms used in Biotechnology.

A) PCR        B) ELISA

C) GEAC        D) GMO


(A) Polymerase Chain Reaction

(B) Enzyme-Linked Immunosorbent Assay

(C) Genetic Engineering Approval Committee

(D) Genetically Modified Organisms

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

17) Isolation of the Genetic Material (DNA) is the first step of recombinant DNA technology. Give an outline about this process.


Isolation of the Genetic Material (DNA):

Treat the bacterial cells/plant or animal tissue with enzymes like lysozyme (bacteria), cellulase (plants), chitinase (fungus) etc. The cell is broken releasing DNA and other macromolecules (RNA, proteins, lipids & polysaccharides).

RNA is removed by treating with ribonuclease. Proteins are removed by treatment with protease. Other molecules are removed by appropriate treatments.

When chilled ethanol is added, purified DNA precipitates out as a collection of fine threads in the suspension.

18) Seeds have many advantages in terms of survival and reproduction. Explain.


Advantages of seeds:

• Since pollination and fertilisation are independent of water, seed formation is more dependable.

• Better adaptive strategies for dispersal to new habitats. It helps the species to colonize in other areas.

• They have food reserves. So seedlings are nourished until they are capable of photosynthesis.

• The hard seed coat protects the young embryo.

• Being products of sexual reproduction, they generate new genetic combinations and variations.

• Dehydration & dormancy helps to store seeds.

19) (a) The pyramid of biomass in sea is generally inverted. Give reason.

(b) What are the limitations of ecological pyramids?


(a) Because the biomass of fishes far exceeds that of phytoplankton.

(b) Limitations of ecological pyramids:

1. It does not consider the same species belonging to two or more trophic levels.

2. It assumes a simple food chain that never exists in nature. It does not accommodate a food web.

3. Saprophytes are not included.

20) (a) Describe the terms (i) Totipotency        (ii) Micropropagation

(b) Mention any two advantages of tissue culture.


(a) (i) Totipotency: The ability to generate a whole plant from any cell/explant is called totipotency.

(ii) Micropropagation: The method of producing thousands of plants in very short time through tissue culture is called micropropagation.

(b) Two advantages of tissue culture:

• Can produce large number of plants which are genetically identical to original plant.

• Tissue culture is used to recover healthy plants from diseased plants.


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

1) Z-values of a frugivorous bat species are given below. Which value is not applicable to continents?

(a) 0.6           (b) 0.65

(c) 0.2           (d) 0.68

✅ (c) 0.2

2) Which of the following combinations do not apply to DNA?

(a) Deoxyribose, Guanine

(b) Ribose, Adenine

(c) Deoxyribose, Uracil

(d) Guanine, Thymine

1. (a) and (b)        2. (b) and (c)

3. (c) and (d)        4. (a) and (d)

✅ 2. (b) and (c)

3) Select the odd one out and justify your selection.

Malaria, Cancer, Amoebiasis, Filariasis

✅ Cancer. It is non-infectious. Others are infectious diseases.

4) Feeding in the first few days is essential for preventing infections in a newly born baby. Why?

✅ The yellowish milk (colostrum) produced during the initial few days of lactation contains several antibodies to develop immunity for newborn babies.

5) Which of the following pairs of STDs is completely curable?

(a) HIV, Hepatitis-B

(b) Hepatitis-B, Gonorrhea

(c) Syphilis, Gonorrhea

(d) Chlamydomonas, genital-herpes

✅ (c) Syphilis, Gonorrhea

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

6) Distinguish in situ conservation from ex situ conservation with one example each.


In situ conservation: It is the conservation of organisms in their natural habitats. E.g. National parks, Sanctuary etc.

Ex situ conservation: It is the conservation of organisms outside their habitats. E.g. genetic resource centres, zoological parks etc.

7) (a) The following table shows the F, generation of a dihybrid cross. Identify the ‘Phenotype’ with homozygous recessive genotype. Find out A : B : C : D.
(b) State Mendel’s Law of Segregation.


(a) Phenotype B.

A: B: C: D = 3:1:9:3

(b) “During gamete formation, the factors (alleles) of a character pair present in parents segregate from each other such that a gamete receives only one of the 2 factors”.

8) LH and FSH are gonadotrophins. Distinguish their roles in males and females.


Functions of LH:

In males: Acts on Leydig cells to stimulate release of androgens.

In females: Stimulates ovulation and development of corpus luteum.

Functions of FSH:

In males: Acts on Sertoli cells to stimulate release of factors for spermiogenesis

In females: Stimulates development of primary follicles to Graafian follicles.

9) Examine the following fragment of beta globin chain in human haemoglobin and identify the hereditary disease with reason.


Sickle cell anaemia.

Reason: Replacement of glutamic acid with valine at the 6th position of -globin chain. This is due to the single base substitution at the sixth codon of the β-globin gene from GAG to GUG.

10) What are the advantages of biofertilizers over chemical fertilizers? Give an example for biofertilizer.


Advantages of biofertilizers: They are eco-friendly and improve soil. They prevent pollution.

E.g. Rhizobium, Mycorrhiza, Cyanobacteria etc.

11) The diagram shown below represents the operation of natural selection on different traits. Observe the diagrams and answer the following.
a. The graph C shows a marked difference from graph A. why?

b. What is the evolutionary significance of directional selection?


(a) In A (Stabilizing selection), more individuals acquire mean character value and variation is reduced.

In C (Disruptive selection), individuals of both extremes (peripheral character value at both ends of the distribution curve) are more favoured.

(b) Directional selection: Here, individuals of one extreme are more favoured. Directional selection drives the evolution of a population towards a specific trait. This helps organisms adapt to changing environments by increasing the prevalence of beneficial traits.

12) Examine the diagram of mRNA given below. Mark the 5’ and 3’ ends of the mRNA by giving reasons.


Reason: Poly adenylation always occurs at 3’ end.
13) Morphine is said to be an abused drug. Discriminate the terms ‘use’ and ‘abuse’ of drugs based on this example.


Use of Morphine: In medical field, it is used as pain killer or sedative.

Abuse: It is abused as narcotic drugs. Produces temporary euphoria and addiction. Affects CNS.

14) Differentiate Active immunity from Passive immunity. Give an example for Passive immunity.


Active immunity: It is the immunity in which antibodies are produced in a host body when the host is exposed to antigens (e.g. living or dead microbes or other proteins).

Passive immunity: Here, readymade antibodies are directly given to the body.

E.g. Antibodies (IgG) from mother → Placenta → Foetus, Anti-tetanus serum (ATS) etc.

15) What would happen if both strands of the DNA act as template for transcription?


• The code for proteins is different in both strands. This complicates the translation.

• If 2 RNA molecules are produced simultaneously, this would be complimentary to each other. It forms a double stranded RNA and prevents translation.

16) Schematic representation of gametogenesis is given below. Identify A and B. Write one difference between A & B.


A= Spermatogenesis        B= Oogenesis

Spermatogenesis: It occurs in testis. No polar body formation.

Oogenesis: It occurs in ovary. Polar bodies are formed.

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

17) One couple came to know that they have a girl child during 4th month of pregnancy and they decide to do MTP.

a. Expand and define MTP.

b. At which stage of pregnancy is MTP relatively safe?

c. How will you respond to the decision of female foeticide by the couple?


(a) Medical Termination of Pregnancy.

Intentional or voluntary termination of pregnancy before full term is called MTP or induced abortion.

(b) At first trimester.

(c) The decision to terminate a pregnancy based on the gender of the child is ethically and morally problematic. Female foeticide is illegal and raises serious concerns about gender discrimination and the value placed on female lives. Also, second trimester is risky.

18) In an E. coli culture lactose is used as food instead of glucose. If so, answer the following questions:

(a) How do the bacteria respond to the above situation at genetic level?

(b) If lactose is removed from the medium what will happen?


(a) If lactose is provided, it is transported into the E. coli. Lactose (inducer) binds with repressor protein. So repressor protein cannot bind to operator gene. The operator gene becomes free and induces the RNA polymerase to bind with promoter gene. Then transcription starts.

(b) Lac operon remains switched off. The regulator gene synthesizes mRNA to produce repressor protein. This protein binds to the operator region and blocks RNA polymerase movement. So the structural genes are not expressed.

19) Examine the pictures of Darwin’s Finches given below and answer the following questions:
(a) What phenomenon in evolution is represented in the picture?

(b) Explain the phenomenon with the help of an additional example.


(a) Adaptive radiation.

(b) Adaptive radiation (evolution by adaptation) is the evolution of different species in a geographical area starting from a point and radiating to other areas of geography (habitats). E.g. Australian marsupials (Marsupial radiation).

Different types of marsupials were evolved from an ancestor but all within the Australian island continent.

When more than one adaptive radiation is appeared in an isolated geographical area, it results in convergent evolution. E.g. Australian Marsupials and Placental mammals.

20) Some genetic abnormalities, their genotypes and features are distributed in columns A, B and C respectively. Match them correctly.


👉 Other Question Papers

👉 Exam Special Materials

Post a Comment (0)
Previous Post Next Post