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Name of the Board : CBSE Academic
Class : XII STD
Subject : Biology
Year : 2015-16

Website : http://cbseacademic.in/SQP_CLASSXII_2015_16.html
Download Sample Question Paper : https://www.pdfquestion.in/uploads/8010Biology.pdf
Download Marking Scheme : https://www.pdfquestion.in/uploads/8010BiologyMS.pdf

CBSE Biology Sample Question Paper

Time allowed : 3 Hrs
Maximum Marks : 70

Related : CBSE Academic Class XII Economics Sample Question Paper 2015-16 : www.pdfquestion.in/8034.html

General Instructions

1. There are a total of 26 questions and five sections in the question paper. All questions are compulsory.
2. Section A contains question number 1 to 5, Very Short Answer type questions of one mark each.
3. Section B contains question number 6 to 10, Short Answer type I questions of two marks each.
4. Section C contains question number 11 to 22, Short Answer type II questions of three marks each.
5. Section D contains question number 23, Value Based Question of four marks.
6. Section E contains question number 24 to 26, Long Answer type questions of five marks each.
7. There is no overall choice in the question paper; however, an internal choice is provided in one question of two marks, one question of three marks and all three questions of five marks. An examinee is to attempt any of the questions out of the two given in the question paper with the same question number.

Section -A

1. 1. Observe the pedigree chart and answer the following questions :
(a) Identify whether the trait is sex-linked or autosomal.
(b) Give an example of a disease in human beings which shows such a pattern of inheritance.

2. Identify the reason for selection of DNA polymerase from Thermus aquaticus for Polymerase Chain Reaction.
3. Govt. of India has raised the marriageable age of female to 18 yrs and of males to 21 yrs. Suggest any two more measures adopted by Government for the purpose.
4. Thymus of a new born child was degenerating right from birth due to a genetic disorder. Predict its two impacts on the health of the child.
5. Give an example of a chromosomal disorder caused due to non-disjunction of autosomes.

Section -B

6. 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.
7. Protein synthesis machinery revolves around RNA but in the course of evolution it was replaced by DNA. Justify.

8. Identify two ways in which Spirulina is helpful to mankind.
OR
Keeping beehives in crop fields has several advantages. List any two.

9. 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.

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

Section -C

11. Explain three outbreeding devices.
12. After implantation interdigitation of maternal and foetal tissues takes place. Identify the tissues involved and justify their role.
13. Compare the two ecological pyramids of biomass given below and explain the situations in which this is possible. Also construct an ideal pyramid of energy if 200,000 joules of sunlight is available.

14. With respect to Messelson and Stahl’s Experiment, answer the following questions
(a) Identify the method used to distinguish between heavy and light isotopes of nitrogen.
(b) With the help of diagrams, compare the results for the DNA isolated after 20 minutes of experiment with the DNA which was isolated after 40 minutes.

15. A student was simulating Urey and Millers experiment to prove the origin of life. The set up used by the student is given –
(a) Find out the reasons why he could not get desired results.
(b) What conclusion was drawn by Urey and Miller through this experiment?
(c) Compare the conclusion drawn with the theory of spontaneous generation ?