User:Archnapandey/Cell Biology Practice Papers

103 CELL BIOLOGY

Time: 3 Hours								Maximum Marks: 50 (ATTEMPT ALL QUESTIONS)

Q1. (a) Fill in the blanks:							(1X9=9) (i)	A centriol contains ________ complete MT and a cilium contains _______ complete MT. (ii)	MT are hollow, tubular structure _______ in diameter that form part of ________ & ________. (iii)	Entry of a cell into M Phase is triggered by the activation of a protein kinase called _________. (iv)	Genetic recombination during meiosis occurs as a result of _______ & ________ of DNA strands. (v)	________ are the specialized sites of contact that blocks solutes from diffusing between the cells in the epithelium.

(b) If 30% of the bases on a single strand of DNA are T, then 30% of the bases on that strand are A. True or False. Why? (2)

(c) Draw the communication junction in plant and animal cells. (3)

Q2. (a) What is cell cycle? What type of synthetic events would you expect to occur during each of these stages?

(b) Contrast the events that occur during cytokinesis in typical plant and animal cells.

(c) Contrast the events that occur during Metaphase I & Metaphase II of meiosis. (3, 3, 3) Q3. (a) How do polytene chromosomes of an insect differ from normal chromosome?

(b) What are the different ways of interaction between the nucleus and the cytoplasm of a cell?

(c) What is the role of Double sex protein in drosophila sex determination? (3, 3, 3)

Q4. (a) Describe three functions of MT. What is the role of GTP in the assembly of MT? What is meant by the term “Dynamic instability of MT”?

(b) Compare and contrast MT assembly and IF assembly. (c) Propose some mechanism that might explain how tobacco mosaic virus was able to alter the permeability of plasmodesmata? (3, 3, 3)

Q5. (a) What is the role of phosphorylation in the action of Na+/K+ ATPase?

(b) Suppose you are culturing a population of bacteria and plant at 37˚C and than dropped the temperature to 15˚C. What effect will this have on the cell membrane? How do you think the two will try to adapt to the fall in temperature?

(c) Compare the rate of lateral movement of a lipid to flip-flop. What is the reason for this difference? (3, 3, 3)