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CBSE Class 12 Biology: 2 Marks questions expected to be asked in 2018 board exam

Feb 14, 2018 12:09 IST
    Important questions for Class 12 Biology
    Important questions for Class 12 Biology

    Important questions for Class 12 Biology are available here. These are expected to be asked in CBSE Class 12 Biology board exam 2018.

    As per latest CBSE Class 12 Biology blueprint, 5 short answer type questions will be asked in the paper; each carrying 2 marks. You can learn more about the examination pattern (or blueprint) of the paper from the link given below

    CBSE Board Exam 2018: Class 12 Biology Examination Pattern

    Science stream students having Biology as one of their subjects are also advised to go through the latest Sample Paper issued by CBSE. With this paper, students will get crystal clear idea about the examination pattern and the level of questions which can be asked in board exam.

    Latest CBSE Sample Papers (Issued by CBSE)

    Important Class 12 Biology questions (carrying two marks) are given below:

    Question: Protein synthesis machinery revolves around RNA but in the course of evolution it was replaced by DNA. Justify.

    Question: How is DNA isolated in purified form from a bacterial cell?

    Question: How can DNA segments, separated by gel electrophoresis, be visualised and isolated?

    Question: How is the translation of mRNA terminated? Explain.

    Question: Identify two ways in which Spirulina is helpful to mankind.

    Question: Keeping beehives in crop fields has several advantages. List any two.

    Question: Evaluate the effect of loss of biodiversity in a region. Mention any two such effects.

    Question: Following are the features of genetic codes. What does each one indicate?

    Stop codon; Unambiguous codon: Degenerate codon: Universal codon.

    Question: Certain species of wasps are seen to frequently visit flowering fig trees. What type of interaction is seen between them and why?

    Question: DDT content in the water of a lake that supplies drinking water to the nearby villages, is found to be 0.003 ppm. The kingfishers of that area were reported to have 2 ppm of DDT.

    Why has the concentration increased in these birds? What harm will this cause to the bird population? Name the phenomenon.

    Question: Construct a grazing food chain and detritus food chain using the following, with 5 links each: Earthworm, bird, snake, vulture, grass, grasshopper, frog, decaying plant matter.

    Question: (a) Name the green house gases that caused global warming.

    (b) Which of them has caused ozone hole and how?

    Question: List the specific symptoms of amoebiasis. Name the causative organism.

    A crane had DDT level as 5 ppm in its body. What would happen to the population of such birds? Explain giving reasons.

    Question: During the secondary treatment of the primary effluent how does the significant decrease in BOD occur?

    Question: Name the cell from which the endosperm of coconut develops. Give the characteristic features of endosperm of coconut.

    Question:

    A woman with blood group O married a man with AB group. Show the possible blood groups of the progeny. List the alleles involved in this inheritance.

    Question:

    A woman with B blood group married a man with A blood group. They had 2 sons and both had O group. Show the possibility of such an inheritance. List the alleles involved in determining the blood group.

    Question: During an excavation assignment, scientists collected pollen grains of a plant preserved in deeper layers of soil. Analyse the properties of pollen grains which help in the fossilization.

    Question: Suryakant had banana plantation in his field. Quality of the fruit was excellent but the yield suffered due to infection of the plants by a virus. Suggest a fast and efficient method to get healthy and a large number of plants in the next generation without compromising on the existing quality. Justify the selection of your method.

    Question: Besides acting as ‘conduits’ for energy transfer across trophic levels, predators play other important roles. Justify.

    Question: The alarming population growth is leading to scarcity of basic requirements. Suggest with reason, any two population control measures other than contraception to address the situation.

    Question: Both Down’s syndrome and Turner’s syndrome are examples of chromosomal disorders. Cite the differences between the two, at the chromosomal level.

    Question: To reduce the percentage of population suffering from hunger and malnutrition, microbes are grown on a large scale to act as food supplements. Mention any two microbes used as food supplement and suggest their role.

    Question: Success rate of artificial insemination in cattle is fairly low. Identify any other technique to improve the successful production of hybrids. State two advantages of this technique.

    Question: (a) A patient who is suffering from myocardial infarction is given a clot buster as part of his treatment. Mention the clot buster administered and its microbial source.

    (b) A person recuperating from illness is advised to have curd regularly. Why?

    Question: Assess the effects of loss of biodiversity in a region. Mention any four such effects.

    Question: The alarming population growth is leading to scarcity of basic requirements.

    Suggest with reasons, any two population control measures other than contraception to address the situation.

    Question: During a cytological study conducted on the chromosomes of the insects, it was observed that only 50% of the sperms had a specific structure after spermatogenesis. Name the structure and write its significance in sex determination of insects.

    Question: To reduce the percentage of population suffering from hunger and malnutrition, microbes are grown on a large scale to act as food supplements. Mention any two microbes used as food supplement and suggest their role.

    Question: A single pea plant in your kitchen garden produces pods with viable seeds, but the individual papaya plant does not. Explain.

    Question: Suggest four important steps to produce a disease resistant plant through conventional plant breeding technology.

    Name a genus of baculovirus. Why are they considered good biocontrol agents?

    Question:

    (a) Expand IUD.

    (b) Why is hormone releasing IUD considered a good contraceptive to space children?

    Question: Name the interaction in each of the following:

    (a) Cuscuta growing on a shoe flower plant.

    (b) Mycorrhizae living on the roots of higher plants.

    (c) Clown fish living among the tentacles of sea anemone.

    (d) Koel laying her eggs in crow’s nest.

    Question: A plant of Antirrhinum majus with red flowers was crossed with another plant of the same species with white flowers. The plants of the F1 generation bore pink flowers. Explain the pattern of inheritance with the help of a cross.

    Question: Why do sports persons often fall victim to cocaine addiction?

    Question: State the difference between the first trophic levels of detritus food chain and grazing food chain.

    Question: Coconut palm is monoecious while date palm is dioecious. Why are they called so?

    Question: How do Darwin’s finches illustrate adaptive radiation?

    Question: Name the blank spaces a, b, c and d from the table given below:

    Type of Microbe

    Name

    Commercial Product

    Bacterium

    a

    Lactic acid

    Fungus

    b

    Cyclosporin A

    c

    Monascus purpureus

    Statin

    Fungus

    Penicillium notatum

    d

    Question:

    In a particular plant species, majority of the plants bear purple flowers. Very few plants bear white flowers. No intermediate colours are observed. If you are given a plant with purple flowers, how would you confirm that it is a pure breed for that trait? Explain.

    Question: Name the interaction in each of the following:

    (a) Clown fish living among the tentacles of sea anemone.

    (b) Sucker fish lives attached to the shark.

    (c) Smaller barnacles disappeared when Balanus dominated in the coast of Scotland.

    (d) Wasp pollinating fig inflorescence.

    Question: Due to undue peer pressure a group of adolescents started using opioids intravenously. What are the serious problems they might face in future?

    Question: How do surgical procedures prevent conception in humans? Mention the way it is achieved in human males.

    Question: Explain the contribution of Thermus aquaticus in the amplification of a gene of interest.

    Question: Banana is a parthenocarpic fruit whereas oranges show polyembryony. How are they different from each other with respect to seeds?

    Question: Where are fimbriae present in a human female reproductive system? Give their function.

    Question: Explain accelerated eutrophication. Mention any two consequences of this phenomenon.

    Question: Describe the responsibility of GEAC, set up by the Indian Government.

    Question: How does Cu-T act as an effective contraceptive for human females?

    Question: Name the hormonal composition of the oral contraceptive used by human females. Explain how it acts as a contraceptive.

    Question: Name the muscular and the glandular layers of human uterus. Which one of these layers undergoes cyclic changes during menstrual cycle? Name the hormone essential for the maintenance of this layer.

    Question: What are recombinant proteins? How do bioreactors help in their production?

    Question: (a) Name the lymphoid organ in humans where all the blood cells are produced.

    (b) Where do the lymphocytes produced by the lymphoid organ mentioned above migrate and how do they affect immunity?

    Question: Where are the Leydig cells present? What is their role in reproduction?

    Question: Explain the dual function of AUG codon. Give the sequence of bases it is transcribed from and its anticodon.

    Question: Explain the cause of algal bloom in a water body. How does it affect an ecosystem?

    Question: List the specific symptoms of typhoid. Name its causative agent.

    Question: Explain metastasis. Why is it fatal?

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