CBSE Set Q Biology Sample Test Papers For Class 12th for students online

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Biology Class-Xll  (CBSE)
You are on questions
Max Marks : 70
Time allowed : 3 hrs

Section A

Question Nos. 1-8 are of very short answer type carrying 1 mark each only.
Answer them in 1-20 words each.

Q1. At what stage is the embryo implanted in the uterus of the mother in the case of a test tube baby?

Q2. Human heart is Myogenic yet a parasympathetic nerve can reduce the heart rate. Name the nerve.

Q3. Which of the following diseases could be avoided by analysing the pedegree of parents –
Klinefelter’s syndrome, Haemophilia, Amoebiasis.

Q4. Name the functional contractile unit of the muscle.

Q5. Name any two synthetic auxins used in agriculture.

Q6. What is pulvinus?

Q7. Name the fluid in which the membranous labyrinth of the inner ear floats.

Q8. In a round worm the volume of the body increases due to the growth of the body cells without increase in their number. What do you call this type of growth?

Section B

Question Nos. 9 – 18 are short answer questions carrying 2 marks each.
It is appropriate to answer them in about 20 – 30 words.

Q9. Why is the cleavage in mammals referred to as simple holoblastic?

Q10. Name the tissue that lines the urinary bladder. State any one advantage of this tissue being present there.

Q11. Draw a labelled diagram of the vertical section of an apple.

Q12. Why is the human male referred to as heterogametic?

Q13. What are the events that take place at the point of stimulation of an axon?

Q14. Write the transcribed m-RNA from the DNA strand with the base sequence of TAG TAC ACT. What is the specific term used for the last codon of the transcribed m-RNA in this case?

Q15. Why is blood group identification not required while transfusing serum?

Q16. The primitive earth had reducing atmosphere to enable abiotic origin of life. What put an end to it?

Q17. How does a sickle-cell carrier have an advantage over the rest of the human population in a Malaria ridden area?

Q18. What acts as an inducer in Lac Operon? How does it switch on the operon?

Section C

Question Nos. 19 – 27 are short answer questions carrying 3 marks each.
It is appropriate to answer them in about 30 – 50 words.

Q19. A Chrysanthemum plant with floral buds requires more than 12 hours of dark night time to flower. If the night is interrupted by white light for duration of an hour, will the flowers bloom the following morning?
Name the pigment that perceives the light stimulus for flowering.
Where is the pigment present in the plant and what are its two forms?

Q20. Define cancer. How are cancers broadly classified pathologically? Name one major cancer in women and one major cancer in men in India.

Q21. State Lamarck’s theory on evolution. Who disproved it and how?

Q22. A farmer has been advised to sow Soyabean seeds inoculated with a bacterial culture. Name the bacterium in the culture. How is this bacterium useful to the crop?

Q23. Draw a labelled diagram showing the longitudinal section of the phloem of an angiosperm with its components.

Q24. Name any three organs homologous to human hand. Why are they considered homologous?

Q25. Give the full form of ADH. Name the gland that secretes it. Under what condition of the body is it released? What is its role in forming hypertonic urine? What disease is caused due to the failure of secretion of this hormone?

Q26. Give one reason why lysozyme is considered an enzyme and not a hormone? How does it defend the body? Name any two secretions in humans, which contain lysozyme.

Q27. Draw a schematic diagram to show the continuous and discontinuous synthesis of DNA and label it.

Section D

Question Nos. 28 – 30 are long answer questions carrying 5 marks each.
It is appropriate to answer them in about 80 – 120 word each.

Q28. Where does spermatogenesis take place? Describe the stages of the process.

Q29. Where does cyclic photophosphorylation occur in the leaves? Explain the events in sequence. Why is the process referred to as cyclic?

Q30. Differentiate between linkage and sex-linked inheritance. Describe the mode of inheritance of any one sex-linked trait in humans.