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CBSE Class 12 Biology Practice Paper 2017: Set ‒ I

Dec 12, 2016 16:00 IST

    Get CBSE class 12 Biology practice paper for the coming CBSE board exam 2017. With the help of questions given in this practice paper, students can analyse their preparation level for the coming CBSE class 12 Biology board exam 2017.

    About CBSE Class 12 Biology Practice Paper 2017:

    In this practice paper there are 27 questions. The examination pattern of this CBSE class 12 Biology practice paper is a bit different from CBSE class 12 Biology question papers.

    In CBSE class 12 Biology question papers there are 26 questions but in this practice paper there are 27 questions. The pattern and level of questions in this practice paper is almost similar to CBSE class 12 Biology question papers. The duration to solve this complete practice paper is of 3 hours.

    CBSE Class 12 Previous Year Question Papers: Solved & Unsolved

    General Instruction for the practice paper:

    There are total of 27 questions and five sections in the question paper. All questions are compulsory.

    Section A contains questions number 1 to 5, very short-answer type questions of 1 mark each.

    Section B contains questions number 6 to 11, short-answer type I questions of 2 marks each.

    Section C contains questions number 12 to 23, short-answer type II questions of 3 marks each.

    Section D contains question number 24, value based question of 4 marks.

    Section E contains questions number 25 to 27, long-answer type questions of 5 marks each.

    CBSE Class 12 Biology Syllabus 2017

    Questions of the complete CBSE Class 12 Biology practice paper are given below:

    Section A

    Question1: Meiosis has to occur for production of haploid gametes in diploid organisms. Justify.

    Question 2: Compare and contrast characters of Ramapithecus and Dryopithecus.

    Question 3: Name the cross that leads to production of mules. Mention the significance of the process.

    Question 4: What does the second amendment of the Indian Patents Bill take into consideration?

    Question 5: Why should the motor vehicles equipped with catalytic converter use unleaded petrol?

    Section B

    Question 6: Production of unisexual flowers prevents autogamy but not geitonogamy while dioecy prevents both autogamy and geitonogamy. Explain.

    Question 7: Same polypeptide chain can be encoded by DNA with more than one type of nucleotide sequence of DNA. Explain.

    Question 8: Mention the breeding strategy used to develop the improved breeds of cattle through conventional animal breeding techniques.

    Question 9: Use of biocontrol measures greatly reduces dependence on toxic chemicals and pesticides. Justify with one example.

    Question 10: The ‘Sixth Extinction’ presently in progress different from the previous episodes. How?

    CBSE Class 12 Biology Sample Paper: 2016

    Question 11: The number of species waiting to be saved from extinction far exceeds the conservation resources available. Give one solution to address this problem.


    Question 11: Draw a labelled diagram of sectional view of human ovary.

    Section C

    Question 12: (a) Mention the reason of statutory ban on amniocentesis.

    (b) Mention the probable reasons behind population explosion in India.

    (c) Mention one step taken by Indian government to tackle the problem of population explosion.


    (a) What is the difference between cleistogamous flowers and chasmogamous flowers?

    (b) Is cleistogamy advantageous or disadvantageous to the plant? Why?

    (c) Geitonogamy is functionally cross-pollination but is genetically similar to autogamy. Justify.

    Question 13: Phenotype of a dominant trait does not tell about genotypic composition. How can you confirm the genotype of a dominant phenotype?

    Question 14: (a) How does Expressed Sequence Tags differ from Sequence Annotation?

    (b) What are microsatellites? Mention their role in Human genome project.

    Question 15: Differentiate between divergent and convergent evolution. Give one example of each.

    Question 16: (a) The immunity provided by mother's milk to new born infant is active or passive? Why and why not? Give one example of each of them.

    (b) Passive immunisation is preferred over active immunisation under emergency condition such as snakebites. Why?

    Question 17: (a) Differentiate between somaclones and somatic hybrids.

    (b) Mention the name of techniques used to produce somaclones and somatic hybrids.

    (c) A farmer wants to obtain healthy crop from his virus infected existing potato crop. Suggest a technique that can be used under the given conditions. Justify giving reason.

    Question 18: (a) How does organic farming provide nutritional supplements to the soil? Give one example.

    (b) Why is the above mentioned approach of fertilizing soil preferred over the use of chemical fertilizers?

    Question 19: (a) Selection of recombinants using antibiotics as selectable markers is a cumbersome process. Justify.

    (b) Mention the alternative approach developed to tackle the above problem of selection of recombinants.

    Question 20: (a) How can the gene therapy serve as permanent cure to genetic diseases? Give one example.

    (b) Molecular diagnosis is preferred over conventional methods of disease diagnosis. Why?  Name three techniques used in molecular diagnosis of diseases.

    Question 21: Mention the methods used to introduce alien DNA into host cells. Give brief description of at least three approaches.

    CBSE Class 12 Biology Online Test

    Question 22: Describe beneficial and detrimental interspecific interactions by giving one example of each.

    Question 23: Why nutrient cycling is also called as biogeochemical cycles? Mention one difference between gaseous and sedimentary cycles. Give one example of each type.

    Section D

    Question 24: Intentional or voluntary termination of pregnancy before full term is called medical termination of pregnancy (MTP) or induced abortion.

    (a) Why in your opinion there is a debate over acceptance of MTP in many countries?

    (b) State any two conditions in favour of MTP.

    (c) Suggest any two measures that can reverse the unhealthy trend associated with MTPs.

    Section E

    Question 25: (a) Describe the structure of mammary glands with well labelled diagram.

    (b) Describe phases of menstrual cycle with respect to uterine and ovarian events.

    (c) Name the respective ovarian and pituitary hormones of different phases of menstrual cycle.


    (a) Name different layers of microsporangial wall. Mention function of each.

    (b) Describe the structure of pollen grain in two celled stage with well labelled diagram.

    (c) Mention the role of pollen bank in conservation of biodiversity.

    Question 26: Who provided first experimental proof of semi conservative nature of DNA replication? Describe the experiment with labelled diagram. Mention the conclusive remarks.


    (a) Differentiate between monocistronic and polycistronic genes.

    (b) "The process of splicing represents the dominance of RNA-world". Justify.

    (c) Describe the post transcriptional modifications of primary transcript of eukaryotes.

    Question 27: (a) Differentiate between two growth models. Give one example of each and draw the respective growth curve.

    (b) Which type of growth curve do you think the seasonal breeders exhibit? Give the reason. 

    (c) Mention the role of carrying capacity in growth curves. How does it differentiate the exponential growth of population from the logistic growth?

    (d) Human population is growing exponentially. Mention the factor that should be altered for transition of a logistically growing population into the one growing exponentially.


    Question 27: (a) Discuss the energy flow in an ecosystem with respect to first and second law of thermodynamics.

    (b) Name the factor that restricts the number of trophic levels in a food chain.

    (c) What are ecological pyramids? Give diagrammatic representation of different types of ecological pyramids.

    (d) For most of the ecosystems, pyramids of number, energy and biomass are upright. Give one exceptional example to the mentioned generalisation about ecological pyramids.

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