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

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PART A: BOTANY

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

1) The density of population in a given habitat increase or decrease due to different reasons. Name two factors responsible for increase in population in a given area.

✅ Natality (B) and Immigration (I).

2) The rate of biomass production in an ecosystem is called productivity. They are of 2 types, gross primary productivity and net primary productivity. How these productivities are related?

✅ NPP = GPP – R

3) From the following, select the two having haploid chromosome number.

a. Egg b. Endosperm

c. Zygote d. Pollen

✅ (a) Egg (d) Pollen

4) Which among the following is a selectable marker in pBR322?

a. Ori b. Hind III

c. amp^R d. rop

✅ (c) amp^R

5) Give two examples for cry genes.

✅ cryIAc, cryIAb, cryIIAb

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

6) A list of different organisms in an ecosystem is given below. Arrange them in 1st, 2nd, 3rd and 4th trophic level.

i. Phytoplankton ii. Man

iii. Fish iv. Zooplankton

✅ Answer

7) In many grasses, seeds are formed only after fertilization. There are reports that in some grasses, seeds are formed without fertilization. Explain the phenomenon.

✅ Answer

Apomixis. It is the production of seeds without fertilisation. E.g. Some species of Asteraceae and grasses.

It is a form of asexual reproduction that mimics sexual reproduction.

In some species, diploid egg cell is formed without reduction division and develops into the embryo without fertilisation.

8) What is stratification? Explain with example.

✅ Answer

Vertical distribution of different species occupying different levels is called stratification. For example, trees occupy top vertical strata or layer of a forest, shrubs the second and herbs and grasses occupy the bottom layers.

9) (a) Identify the picture A and B.

(b) What is meant by the terms syncarpous and apocarpous?

✅ Answer

(a) A= Multicarpellary, syncarpous pistil of Papaver

B= A multicarpellary, apocarpous gynoecium of Michelia.

(b) Syncarpous: This is a condition in which the pistils of the gynoecium are fused together.

Apocarpous: This is a condition in which the pistils of the gynoecium are free.

10) Imagine you are appointed as biotechnologist in a National Institute. What are the basic steps to be designed to produce a genetically modified organism? (Hint: 3 points)

✅ Answer

Basic steps in genetically modifying an organism:

• Identification of DNA with desirable genes.
• Introduction of the identified DNA into the host using a vector DNA.
• Maintenance of introduced DNA in the host and transfer of the DNA to its progeny.

11) (a) In a pond, there were 30 lotus plants last year and through reproduction 14 new plants are added. Calculate birth rate.

(b) Besides birth rate, mention any two attributes of a population.

✅ Answer

(a) Birth rate= Number of new plants/Initial number of plants.

= 14/30 = 0.466 offspring per lotus per year.

(b) Death rate, Sex ratio.

12) Alpha-I antitrypsin and alpha-lactalbumin are two biological products produced from transgenic animals. Write the uses of these two products.

✅ Answer

Use of Alpha-I antitrypsin: To treat emphysema.

Use of alpha-lactalbumin: Nutritionally more balanced product for human babies than natural cow-milk.

13) Use of a thermostable DNA polymerase from the bacterium, Thermus aquaticus, made it possible to generate billion copies of DNA in a very short time using a process.

a. Name the process.

b. Name the three important steps involved in this process.

✅ Answer

(a) Polymerase Chain Reaction (PCR).

(b) Denaturation, Annealing & Extension

14) Parasitism is a type of interspecific interaction where one (parasite) is benefitted and the other (host) is harmed. Explain two types of parasites with examples.

✅ Answer

1. Ectoparasites: Parasites that feed on the external surface of host. E.g. Lice on humans, Cuscuta plant on hedge plants

2. Endoparasites: Parasites that live inside the host body at different sites (liver, kidney, lungs, RBC etc). e.g., Ascaris.

15) Name the following:

a. A nematode that infects the roots of tobacco plants.

b. A cellular defense mechanism in all eukaryotes that was used as a novel strategy to prevent this infestation.

c. A vector used to introduce nematode-specific genes into the host plant.

d. Mobile genetic elements used as a source of complementary RNA for RNAi.

✅ Answer

(a) Meloidegyne incognitia

(b) RNA interference (RNAi)

(d) Transposons

16) Analyze the given graphical representation.

a. Identify the curves C₁ and C₂.

b. Write down the equations E₁ and E₂.

✅ Answer

(a) C₁= Exponential (Geometric) growth curve.

C₂= Logistic (Sigmoid) growth curve.

(b) Equation E₁ is

Equation E₂ is

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

17) The discovery of Restriction Endonuclease is considered as a milestone in the history of genetic engineering.

a. Which is the first discovered restriction endonuclease?
b. What are the criteria for naming of restriction endonuclease?

✅ Answer

(a) Hind II.

(b) First capital letter: Genus name.

Second two letters: Species name.

Fourth letter: Strain of bacterium from which the enzyme is isolated.

Roman number: Order of isolation of enzyme.

18) In plants, the developmental stages of male gametes consist of microsporogenesis and male gametophyte. Arrange the following terms in their correct developmental sequence.

Pollen grain
Sporogenous tissue
Anther
Microspore tetrad
Pollen mother cell
Male gamete

✅ Answer

Anther
↓
Sporogenous Tissue
↓
Pollen Mother Cell
↓
Microspore Tetrad
↓
Pollen Grain
↓
Male Gamete

19) Although biotechnology offers many benefits to humans, it also raises some ethical issues.

a. Explain any two ethical issues regarding application of biotechnology.
b. State any two steps taken by the Government of India to overcome such problems.

✅ Answer

(a) Ethical issues regarding application of biotechnology:

i. Problem of unpredictable results: Genetic modification may cause unpredictable results.

ii. Biopiracy: It is the use of bio-resources by multinational companies and other organizations without proper authorization from the countries and people concerned.

(b) Steps taken by the Government of India:

• To solve the problem of unpredictable results: Organizations like GEAC (Genetic Engineering Approval Committee) to make decisions about the validity of GM research and the safety of GM-organisms for public services.

• To solve the problem of Biopiracy: Indian Parliament has cleared the second amendment of the Indian Patents Bill that has considered patent terms emergency provisions and research and development initiative.

20) (a) What are decomposers? Give two examples.

(b) Suggest another name for decomposers.

✅ Answer

(a) Decomposers are heterotrophic organisms that meet their energy and nutrient requirements by degrading dead organic matter or detritus. E.g., fungi and bacteria.

(b) These are also known as saprotrophs.

(c) Decomposers secrete digestive enzymes that breakdown dead and waste materials into simple, inorganic materials, which are subsequently absorbed by them.

PART B: ZOOLOGY

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

1) Which of the following do not have similar sex chromosomes (Homogametic)?

(a) Human female (b) Drosophila female

✅ (c) Bird female

2) Which among the following does not belong to Assisted Reproductive Technology?

(a) ICSI (b) IUD

✅ (b) IUD

3) Note the relationship between the terms of first pair and fill up the fourth place.

Prokaryotes: Polycistronic structural gene

Eukaryotes: ……………….

✅ Monocistronic structural gene

4) Which of the following sets of gases were used in Miller’s experiment?

(a) CH₄, NO₂, H₂O, CO₂

(b) NH₃, NO₂, H₂O, H₂

(d) H₂O, N₂, CH₄, H₂

✅ (c) H₂, CH₄, NH₃, H₂O

5) Diagram of mammalian sperm is given. Label the marked parts.

✅ A= Acrosome B= Nucleus

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

6) Symptoms of some diseases are given below. Identify the diseases.

a. Chill and high fever recurring every 3-4 days.

b. Internal bleeding, muscular pain, blockage of intestinal passage.

c. Chronic inflammation of the limbs, deformity of limbs and genital organs.

d. Dry, scaly lesions on skin, nails, scalp etc. Intense itching.

✅ Answer

(a) Malaria (b) Ascariasis

7) One of your neighbors is suffering from itching, fluid discharge, slight pain and swelling in genital region.

a. What do you think the disease he is suffering from?

b. What measures are to be taken to prevent such disease?

✅ Answer

(a) Sexually Transmitted Infections (STI).

(b) Prevention:

• Avoid sex with unknown partners/multiple partners.
• Always use condoms during coitus.
• In case of doubt, consult a qualified doctor for early detection and get complete treatment.

8) Distinguish between homologous and analogous organ with one example for each.

✅ Answer

Homologous organs are the organs having fundamentally similar structure and origin but different functions. E.g., Human hand, Whale’s flippers, Bat’s wing & Cheetah’s foot.

Analogous organs are the organs having similar function but different structure & origin. E.g. Wings of butterfly and wings of birds.

9) (a) Mention any two desirable features of a better contraceptive method.

(b) Write any two advantages of Saheli over conventional contraceptive pills.

✅ Answer

(a) User-friendly, easily available, effective and reversible. No or least side-effects.

(b) Saheli is a ‘once a week’ pill with very few side effects and high contraceptive value.

10) Briefly explain the steps of processing of hnRNA in eukaryotes to form mRNA.

✅ Answer

Steps of processing of hnRNA:

a. Splicing: From hnRNA, introns are removed (by the spliceosome) and exons are spliced (joined) together.
b. Capping: Here, a nucleotide methyl guanosine triphosphate (cap) is added to the 5’ end of hnRNA.
c. Tailing (Polyadenylation): Here, adenylate residues (200-300) are added at 3’-end.

11) “Gopalan argues that if father is of ‘A’ blood group, mother is of ‘B’ blood group. Their children can only be ‘A’ group, ‘B’ group or ‘AB’ group.”

a. Do you agree with Gopalan’s argument?

b. Give reason for your answer.

✅ Answer

(a) No. I do not agree.

(b) If parents have heterozygous genotypes of blood group, the children may have O group.

12) a) Complete the flowchart of chromosomal disorders by filling the blank boxes (A and B).

b) What is aneuploidy?

✅ Answer

a) A= Monosomy of sex chromosome

B= Klinefelter’s syndrome

b) Aneuploidy is the gain or loss of chromosomes due to failure of segregation of chromatids during cell division.

13) Read carefully the sequence of codons in the mRNA unit and answer the questions.

a. What change is needed in the first codon to start the translation process?

b. If translation starts by that change, till which codon it can continues? Why?

✅ Answer

(a) AUA should be changed to AUG.

(b) Till 5th codon (UUU). After that there is a stop codon (UGA) which terminates translation.

14) BOD of some water samples are given below:

A. Sample 1 - 200 mg/L

B. Sample 2 - 80 mg/L

C. Sample 3 - 300 mg/L

D. Sample 4 - 25 mg/L

a. Which of the above water sample is most polluted?

b. What is meant by flocs? What is its role in sewage treatment?

✅ Answer

(a) Sample 3. As a higher BOD indicates a greater degree of pollution.

(b) Flocs are clumps of bacteria and fungal filaments that come together during the sewage treatment.

In the treatment process, flocs help in removing organic wastes from the water. Thus water is cleared.

15) Observe the diagram and answer the questions:

a. Identify the process shown in the figure and define it.

b. Identify the structure B. Write any one function of it in the process shown in the diagram.

✅ Answer

(a) The process is Translation. It is the process of polymerization of amino acids to form a polypeptide (protein) based on the sequence of codons in mRNA.

(b) B is the subunits of ribosome. It acts as the site of translation.

16) Match the following:

✅ Answer

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

17) “Nature provides all for the need of man but not for his greed.”

a. Do you agree with this statement? Justify your answer.

b. There are 3 categories of reasons for conservation of biodiversity. Mention them.

✅ Answer

(a) Yes, I agree.

Nature has enough resources to fulfill everyone’s needs if used wisely and sustainably. However, human activities such as habitat loss and fragmentation, overexploitation etc. lead to depletion of these resources, causing harm to the environment and future generations.

(b) Narrowly utilitarian arguments, Broadly utilitarian arguments and Ethical arguments.

18) Observe the diagram, and answer the questions:

a. Identify A and B.

b. What is the function of C?

c. In which of the marked part reduction division takes place? What is the significance of it?

✅ Answer

(a) A= Spermatozoa B= Spermatogonium

(b) C (Sertoli cell) Sertoli cells provide nutrition to the germ cells.

Significance: It leads to formation of two equal, haploid cells called secondary spermatocytes, which have only 23 chromosomes each.

19) “Prediction of the sequence of amino acids from the nucleotide sequence in mRNA is very easy, but the exact prediction of the nucleotide sequence in mRNA from the sequence of amino acids coded by mRNA is difficult.”

a. Which properties of the genetic code is the reason for above condition? Explain.

b. AUG has dual functions. What are they?

✅ Answer

(a) (i) An amino acid is coded by more than one codon (except AUG for methionine & UGG for tryptophan). Such codons are called degenerate codons.

(ii) Genetic code is unambiguous and specific. i.e., one codon specifies only one amino acid.

(b) (i) AUG codes for Methionine.

(ii) It also acts as initiator codon.

20) Prepare a pamphlet for an awareness programme in your school about the measures to prevent and control alcohol and drug abuse in adolescents.

✅ Answer

Pamphlet:

Prevent and Control Alcohol and Drug Abuse in Adolescents

Alcohol and drug abuse can lead to serious health issues, poor academic performance, and strained relationships.

Prevention and control

• Avoid undue peer pressure.

• Education and counselling.

• Seeking help from parents and peers.

• Looking for danger signs.

• Seeking professional and medical help.

▪️ Psychologists & psychiatrists.

▪️ De-addiction & rehabilitation programs.

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Plus Two Biology (Bot + Zoo) | Practice Model Question Paper PDF with Answer key | SET 9