Plus Two Biology (Bot + Zoo) | Practice Model Question Paper PDF with Answer key | SET 1

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PART A: BOTANY

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

1) Choose the correct answer and fill in the blank.

...................... is the female gametophyte of angiosperms.

(a) Embryo sac
(b) Nucellus
(c) Integument
(d) Pollen grain

✅ (a) Embryo sac

2) Name the type of interaction between an Orchid plant and Mango tree.

✅ Commensalism

3) Net Primary Productivity (NPP) = …………...

✅ Gross primary productivity – respiration (GPP – R)

4) Which group of enzymes are known as ‘molecular scissors’?

✅ Restriction enzymes

5) Plants, bacteria, fungi and animals whose genes have been altered by manipulation are called ……………

✅ Genetically Modified Organisms (GMO).

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

6) The innermost wall layer of Microsporangium is Tapetum.

(a) What is its function?
(b) Write two features of Tapetal cells.

✅ Answer

a) It nourishes the developing pollen grains.
b) Cells of the tapetum possess dense cytoplasm and generally have more than one nucleus.

7) Explain the separation of DNA fragments using gel electrophoresis.

✅ Answer

The DNA fragments can be separated by a technique known as gel electrophoresis. DNA fragments are negatively charged. So they move towards the anode under an electric field through a medium/matrix such as agarose gel. The DNA fragments separate according to their size through sieving effect of the agarose gel. The smaller sized fragment moves farther.

8) Write notes on:

(a) Microinjection          (b) Biolistics

✅ Answer

Microinjection and Biolistics are two methods to introduce alien DNA into host cells.
(a) Microinjection: In this method, recombinant DNA is directly injected into the nucleus of an animal cell.
(b) Biolistics (gene gun): In this, cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA. It is suitable for plants.

9) Define:

(a) Apomixis          (b) Polyembryony

✅ Answer

(a) Apomixis is the production of seeds without fertilisation.
(b) Occurrence of more than one embryo in a seed is called Polyembryony.

10) Field survey by a team of students recorded the following data related to number of organisms in an ecosystem and plotted that into a figure shown below:

Observe the figure and explain the pyramid.

✅ Answer

It is an inverted pyramid of number. If a plant takes an ecosystem number of producer is one more than herbivorous insects, birds, etc. It is 2nd trophic level. 3rd trophic level contains more parasites than herbivores. 4th trophic level contains more hyperparasites than 3rd trophic level parasites.

11) Observe the diagram and answer A and B.

✅ Answer

A= Proinsulin      B= Insulin.

12) (a) Define transgenic animals.

    (b) Write any two uses of transgenic animals.

✅ Answer

(a) Transgenic animals are the animals whose genome has been altered by introduction of a foreign gene by manipulation.
(b) Uses of transgenic animals:
• To study regulation of genes and their action on normal physiology & development.
• To study the contribution of genes in the development of a disease and thereby new treatments.
• Biological products.
• Vaccine safety testing.
• Chemical safety testing (toxicity testing).

13) Humification and Mineralization occur during decomposition in the soil. Write the difference between these twoprocesses.

✅ Answer

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

14) Given below in the diagram showing the transfer of pollen grains.

(a) Identify P1 & P2 with technical terms.
(b) Critically evaluate P1 & P2.

✅ Answer

(a) P1= Autogamy (self-pollination)      P2= Geitonogamy
(b) Autogamy: In flowers with exposed anthers & stigma, complete autogamy is rare. Autogamy in such flowers requires synchrony in pollen release and stigma receptivity.
Geitonogamy: It is functionally cross-pollination involving a pollinating agent. But it is genetically similar to autogamy since the pollen grains come from same plant.

15: Observe the equation.

(a) Which type of growth curve does it represents?
(b) What do the following notations represent?
      i. N      ii. r      iii. K

✅ Answer

(a) Logistic Growth Curve.

(b) i. N = Population density at time t
ii. r = Intrinsic rate of natural increase
iii. K = Carrying capacity

16: (a) Construct a Grazing Food Chain (GFC) using the following organisms:

Bird, Grass, Grasshopper

(b) Write the trophic level of grasshopper.

✅ Answer

(a) Grass → Grasshopper → Bird
(b) Second trophic level (Primary consumer).

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

17) Raman is learning the post fertilization changes of an angiosperm embryo sac with the help of slides. He identifiedthe egg nucleus and polar nuclei with the help of his teacher.

(a) Name the other nuclei present in the embryo sac.
(b) Help Raman by giving the changes that takes place with egg nucleus and polar nucleus after fertilization.

✅ Answer

(a) Two synergids, Three antipodal cells, One central cell.
(b) After fertilization, the following changes take place:
• The egg nucleus fuses with one of the sperm cells to form a diploid zygote. This zygote will further develop into the embryo.
• The two polar nuclei fuse with the other sperm cell to form a triploid cell. This triploid cell develops into the endosperm, which provides nutrition to the developing embryo. This process is known as double fertilization. It is a unique feature of angiosperms and results in the formation of a seed containing an embryo (from the zygote) and endosperm (from the triploid cell).

18) Density of a population fluctuates due to changes in four basic processes.

(a) Complete the diagram by adding the points A B C and D.
(b) Explain A and D.

✅ Answer

(a) A= Immigration (I)
B= Natality (B)
C = Mortality (D)
D= Emigration (E)

(b) Natality (B): It is the number of births in a population during a given period.
Mortality (D): It is the number of deaths in a population during a given period.
Immigration (I): It is the number of individuals of the same species that have come into the habitat from elsewhere during a given time period.
Emigration (E): It is the number of individuals of the population who left the habitat and gone elsewhere during a given time period.

19) (a) What is meant by gene therapy?

(b)Briefly explain the reason for ADA deficiency disorder.
(c)Mention a treatment method for ADA deficiency.

✅ Answer

(a) Gene therapy is a method to correct a gene defect in a child/embryo.
(b) This is caused due to the deletion of a gene of adenosine deaminase (an enzyme for the functioning of immune system).
(c) Gene therapy for ADA deficiency: Collect lymphocytes from the patient’s blood and grow in a culture → Introduce a functional ADA cDNA into lymphocytes (using a retroviral vector) → return them to the patient.

20) Amplification of gene of interest is done using PCR.

(a) Expand PCR.
(b) Mention the three steps of this process.
(c) What are primers?

✅ Answer

(a) Polymerase Chain Reaction.

(b) Three steps of PCR:
Denaturation: Heating of DNA sample to separate into single strands.
Annealing: Joining of the two primers at the 3’ end of the DNA templates.
Extension: A new strand of DNA is synthesized from the primers.

(c) Primers are short, single-stranded DNA sequences that are complementary to the target DNA sequence. They provide a starting point for DNA synthesis during PCR.

PART B: ZOOLOGY

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

1) The theory which states that the units of life were transferred to different planets including earth is ....................

✅ Theory of Panspermia

2) Identify the odd one out. Justify your answer.

UAA, AUG, UAG, UGA

✅ AUG. It is a start codon. Others are stop codons.

3) The regions with very high species richness, high degree of endemism but most threatened is

(a) Sacred groves
(b) Hotspots
(c) National parks
(d) Sanctuary

✅ (b) Hotspots

4) Which of the following is cytokine barrier?

(a) Neutrophil
(b) Lysozymes
(c) Mucus
(d) Interferons

✅ (d) Interferons

5) Note the relationship between the first two words and fill up the fourth place.

LNG-20: Hormone releasing IUD
Multiload 375: ………………..

✅ Copper releasing IUD

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

6) Given below are the steps of experiments conducted by Frederick Griffith. Complete the remaining steps.

• S-strain → Inject into mice → Mice die
• R-strain → Inject into mice → Mice live
• .............................
• ..............................

✅ Answer

• S-strain (heat killed) → Inject into mice → Mice live
• S-strain (heat killed) + R-strain (live) → Inject into mice → Mice die

7) Correct the false statements given below (consider the words underlined).

a. Progesterone level is increased during proliferative phase.
b. Menopause is the first menstruation in the life of a woman.

✅ Answer

a. Progesterone level is increased during Luteal (Secretory) phase.
b. Menarche is the first menstruation in the life of a woman.

8) To find out the unknown genotype of violet flowered pea plant, a researcher done the following cross. Observe the diagram and answer the following questions.

a. What would be the above cross is called?
b. Can you determine the unknown genotype of violet flowered parent by drawing Punnett square?

✅ Answer

a. Test cross.
b. Yes.

9) “Chromosomal theory of inheritance was proved through several dihybrid crosses using fruit flies (Drosophila melanogaster).”

a. Who conducted this experiment?
b. Why did he select Drosophila as the experimental material? (Any three reasons).

✅ Answer

a. T.H Morgan
b. Morgan selected Drosophila as the experimental material because
• They can be grown on simple synthetic medium.
• They complete their life cycle in about two weeks.
• A single mating can produce a large number of progeny flies.
• Male and female flies are easily distinguishable.
• It has many types of hereditary variations that can be seen with low power microscopes.

10) Diagram shown below is a surgical method used for male sterilization.

a. Name the method shown in the diagram.
b. What is the surgical method of female sterilization called?
c. What are the advantages of condoms over this method? (Any two).

✅ Answer

a. Vasectomy.
b. Tubectomy.
c. Condoms are reversible. Condoms protect the user from STIs and AIDS.

11) “More and more children in metro cities of India suffer from allergies and asthma.” Justify this statement.

✅ Answer

Modern-day life style and protected environment provided early in life result in low immunity and more sensitivity to allergens. So, many children in metro cities suffer from allergies and asthma.

12) Metastasis and lack of Contact inhibition are two properties of cancer cells. What do you understand by these two terms?

✅ Answer

▪️ Metastasis: Cells sloughed from tumours reach other sites via blood where they form a new tumour. It is called metastasis.
▪️ Contact inhibition: It is a property of normal cells where contact with the other cells inhibits their uncontrolled growth.

13) Government of India legalised MTP in 1971 with some strict conditions to check illegal female foeticides.

a. What is MTP?
b. Mention any two importance of MTP.

✅ Answer

a. Intentional or voluntary termination of pregnancy before full term is called MTP (Medical Termination of Pregnancy).
b. importance of MTP:
• To avoid unwanted pregnancies due to casual sex or failure of the contraceptive used during coitus or rapes.
• It is essential in cases where continuation of pregnancy could be harmful to the mother or foetus or both.

14) Arrange the following in hierarchical manner based on the period of their evolution.

Homo erectus, Ramapithecus, Australopithecus, Homo sapiens, Neanderthal man, Dryopithecus, Homo habilis

✅ Answer

Dryopithecus → Ramapithecus → Australopithecus → Homo habilis → Homo erectus → Neanderthal man → Homo sapiens

15) Observe the diagram shown below.

a. Identify the diagram.
b. Label A, B & C.

✅ Answer

a. Transcription Unit.
b. A= Promoter, B= Terminator, C= Coding strand.

16) Fill the columns A & B using the words given below.

(Lamarckism, Development of DDT resistant ants, Gene flow by chance, Adaptive radiation, de Vries)

✅ Answer

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

17) Steps of DNA fingerprinting are shown below.
a. Complete the flow chart given below and answer the following questions.

b. Mention the principles behind the DNA fingerprinting.
c. DNA fingerprinting is a gift to forensic science. Do you agree? Give reason.

✅ Answer

a. (i) Digestion of DNA by restriction endonucleases.
(ii) Hybridization using radioactive labelled VNTR probe.
b. DNA carries some non-coding repetitive sequences. A DNA sequence which is tandemly repeated in many copy numbers is called variable number tandem repeats (VNTR). VNTR is specific from person to person.
c. Yes. Because DNA fingerprinting is a forensic tool to solve paternity, rape, murder etc.

18) “Placenta is a structural and functional unit between foetus and maternal body”.

a. Name the foetal and maternal parts that are interdigitated to form placenta.
b. Why it is considered as structural and functional unit? (Any 2 reasons).
c. Placenta also acts as an endocrine gland. Do you agree? Justify.

✅ Answer

a. Foetal part is chorionic villi. Maternal part is Uterine tissue (endometrium).
b. It supplies O2, nutrients etc. from mother to foetus. Removes CO2 and excretory wastes from foetus.
c. Yes. Placenta secretes Human chorionic gonadotropin (hCG), human placental lactogen (hPL), oestrogens, progesterone & Relaxin.

19) Match the column A with column B.

✅ Answer

20) Gopalan cultivated a variety of fruit crops and plants in his field and Raman destroyed the fruit crops and plantsand cultivated rubber trees which are double in number.

a. In your opinion, which method is suitable for the ecosystem? Give reason.
b. Mention any three factors that lead to the extinction of species.

✅ Answer

a. The method of Gopalan is more suitable for the ecosystem. Diverse cultivation provides habitats for various species, promoting soil health and ecological balance.
b. (i) Habitat loss and fragmentation.
(ii) Overexploitation
(iii) Alien species invasion.
(iv) Coextinction.

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