👉 Download Biology Question Paper PDF - SET 8
PART A: BOTANY
I. Answer any 3 questions from 1 – 5. Each carries 1 score. (3 x 1 = 3)
a) Mutualism b) Predation
c) Commensalism d) Parasitism
✅ c) Commensalism
✅ Syngamy
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’
a) Earthworm b) Virus
c) Fox d) Cow
✅ a) Earthworm
✅ B= Bacillus t= thuringiensis
II. Answer any 9 questions from 6 – 16. Each carries 2 scores. (9 x 2 = 18)
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
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(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
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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).
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A= Antipodal B= Polar nucleiC= Egg cell D= Synergid
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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.
a. Cleistogamous flowers are autogamous. Justify.
b. Define autogamy.
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(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.
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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.
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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.
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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.
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(x) Post-reproductive(y) Reproductive
(z) Pre-reproductive
(a) Expanding (growing)
(b) Stable
(c) Declining
A) PCR B) ELISA
C) GEAC D) GMO
✅ Answer
(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)
✅ Answer
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.
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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.
(b) What are the limitations of ecological pyramids?
✅ Answer
(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.
(b) Mention any two advantages of tissue culture.
✅ Answer
(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.
PART B: ZOOLOGY
I. Answer any 3 questions from 1 – 5. Each carries 1 score. (3 x 1 = 3)
(a) 0.6 (b) 0.65
(c) 0.2 (d) 0.68
✅ (c) 0.2
(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)
✅ Cancer. It is non-infectious. Others are infectious diseases.
✅ The yellowish milk (colostrum) produced during the initial few days of lactation contains several antibodies to develop immunity for newborn babies.
(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)
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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.
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(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”.
✅ Answer
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.
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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.
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Advantages of biofertilizers: They are eco-friendly and improve soil. They prevent pollution.E.g. Rhizobium, Mycorrhiza, Cyanobacteria etc.
b. What is the evolutionary significance of directional selection?
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(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.
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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.
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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.
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• 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.
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A= Spermatogenesis B= OogenesisSpermatogenesis: 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)
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?
✅ Answer
(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.
(a) How do the bacteria respond to the above situation at genetic level?
(b) If lactose is removed from the medium what will happen?
✅ Answer
(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.
(b) Explain the phenomenon with the help of an additional example.
✅ Answer
(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.
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