CBSE Set Q Biology Sample Test Papers For Class 12th for students online
You are on questions of Section A,B,C,D
Max Marks : 70
Time allowed : 3 hrs
Section - A
Q.Nos. 1-8 are of very short answer
type carrying 1 mark each. Answer them in one word/one sentence having 1-20
words each.
Q 1. What is meant by trisomic condition? 1 mark
Q 2. State the presence or absence of sinus venous in a fish and a mammal. 1
mark
Q 3. Which type of cartilage is present between vertebrae to allow limited
movement? 1 mark
Q 4. Name any two breeds of wild rock pigeon that have been developed through
artificial selection. 1 mark
Q 5. Which chromosomes are called autosomes? 1 mark
Q 6. When is a tumour referred to as malignant? 1 mark
Q 7. What are the two factors that contribute for the dissociation of
oxyhaemoglobin in the arterial blood to release molecular oxygen in an active
tissue? 1 mark
Q 8. Which one of the following is fatal unless oral rehydration therapy is
administered:
(i) Whooping cough (ii) Cholera (iii) Tetanus 1 mark
Q. Nos. 9-18 are of short answer type carrying 2 marks each. Answer them in
approximately 20-30 words each.
Q 9. What are the two functions of DNA polymerase? 2 marks
Q 10. Stanley Miller and Harold C. Urey performed an experiment by recreating in
the laboratory the probable conditions of the atmosphere of the primitive earth.
(i) What was the purpose of the experiment?
(ii) In what forms was the energy supplied for the chemical reactions to occur?
(iii) For how long was the experiment run continuously? 2 marks
Q 11. How does the mustard inflorescence differ from the banana inflorescence in
arrangement? Give the technical term for each. 2 marks
Q 12. Name the basic nitrogenous catabolite of proteins produced in birds. In
what form is it eliminated from their body? What is the advantage of this type
of excretion? 2 marks
Q 13. Describe the theory of inheritance of acquired characters. Who disproved
it experimentally? 2 marks
Q 14. Differentiate between morula and blastula of mammals. 2 marks
Q 15. What is the biological significance of Azolla pinnate in agriculture? 2
marks
Q 16. Give any two reasons to justify that ginger is a modified stem. 2 marks
Q 17. Define biogeography. How do Darwin's Finches provide the biogeographical
evidence in favour of evolution? 2 marks
Q 18. Explain the structural and functional significance of fovea in the human
eye. 2 marks
Q. Nos. 19-27 are of short answer type carrying 3 marks each. Answer them in
approximately 30-50 words each.
Q 19. What is meant by R cells and S cells with which Frederick Griffith carried
out his experiments on Diplococcus pneumoniae? What did he prove from these
experiments? 3 marks
Q 20. Draw a diagram of the T.S. of a part of seminiferous tubule of testis of
an adult human male and label any six parts in it.
Q 21. How does industrial melanism bring out the action of natural selection? 3
marks
Q 22. How does intestinal juice contribute in the digestion of proteins? What
provides alkaline pH in the small intestine? 3 marks
Q 23. An mRNA strand has a series of codons out of which three are mentioned
below.
(i) AUG, (ii) UUU and (iii) UAG
(a) What will these codons be translated into?
(b) What are the DNA codons that would have transcribed these RNA codons? 3
marks
Q 24. List any four symptoms shown by a Down's syndrome afflicted child. Explain
the cause of this disorder. 3 marks
Q 25. Answer the following with reference to the anatomy of a dicot stem :
(i) Where exactly are the cambial
cells located in the vascular bundles?
(ii) What is the name given to such a bundle?
(iii) How are the xylem vessels arranged?
(iv) What type of cells constitute the pith? 3 marks
Q 26. Explain any three chemical barriers that offer a non-specific defence
mechanism. 3 marks
Q 27. Trace the development of microsporocyte in the anther of a mature
pollen-grain. 3 marks
Q.Nos. 28-30 are long answer type carrying 5 marks each. Answer them in
approximately 80 - 120 words each.
Q 28. In the case of snapdragon (Antirrhinum majus) a plant with red flowers was
crossed with another plant with white flowers. Trace the inheritance of flower
colour up to the F2 generation indicating the genotypesand phenotypes
at each level. What special feature do you note in the genotypic ratios in the F2
generation? 5 marks
Q 29. Name the hormone that regulates each of the following and mention the
source of it :
(i) Urinary elimination of water
(ii) Storage of glucose as glycogen
(iii) Sodium and potassium ion metabolism
(iv) Basal metabolic rate
(v) Descent of testes into the scrotum 5 marks
Q 30. Describe the C4 pathway in a paddy plant. How is this pathway
an adaptive advantage to the plant? 5 marks