Code No. : 8421 Sub. Code : HZOM 13

Transcription

1 (6 pages) Reg. No. :... Sub. Code : HZOM 13 M.Sc. (CBCS) DEGREE EXAMINATION, APRIL First Semester Zoology DEVELOPMENTAL BIOLOGY (For those who joined in July 2012 onwards) Time : Three hours Maximum : 75 marks PART A (10 1 = 10 marks) Answer ALL questions. Choose the correct answer : 1. An occyte is fertilized in the. (a) Vagina (b) Fallopian Tube (c) Uterus (d) Ovary 2. The human sperm head is covered by a membrane enclosed structure called. (a) Head (b) Neck (c) Middle piece (d) Acrosome

2 3. The spiral pattern of cleavage is seen in (a) Synapta (b) Amphioxus (c) Annelids (d) None of these 4. The cell division seen during cleavage is (a) Mitotic cell division (b) Meiotic cell division (c) A mitotic cell division (d) None of these 5. Morphogentics responses may be included in organisms by. (a) Hormones only (b) Environmental chemicals only (c) Both (a) and (b) (d) None of these 6. Class of molecules involved in morphogenesis are transaction factor proteins that determines the fate of cells by. (a) Avoiding DNA (b) Interacting with t-rna (c) Interacting with DNA Page 2

3 (d) Interacting with m-rna 7. The origin of digestive tract is from (a) Ectoderm (b) Endoderm (c) Mesoderm (d) Neuroderm 8. The edges of neural plate are folded and elevated to form (a) Medullary plate (b) Neural fold (c) Neural groove (d) Neural tube 9. The theory of organizer was formulated by (a) Tidemann (b) Robert Brown (c) Spemann (d) None of them 10. The inductor causes induction by liberating a chemical substance called (a) ganizer chemical Page 3

4 (b) Evocator (c) Belly - piece (d) None of these PART B (5 5 = 25 marks) Answer ALL questions, choosing either (a) or (b). Each answer should not exceed 250 words. 11. (a) Describe the various events associated with spermatogenesis. (b) Explain the polarity of ovum production. 12. (a) Describe the types of cleavage in human reproductive system. (b) Write short notes on cleavage and blastulation in frog developmental system. 13. (a) Describe the series of normal stages in the development of the Sea Urchin. (b) Describe the model for pattern formation within the vertebrate body plan. Page 4

5 14. (a) Write a brief notes on development of mesodermal organs. (b) Explain the formation of digestive tract and its derivatives in human developmental system. 15. (a) Give an account on embryonic induction [P.T.O.] in vertebrates. (b) Write a short note on control of differentiation at transcription and translation level and changing pattern of protein synthesis in developmental biology. PART C (5 8 = 40 marks) Answer ALL questions, choosing either (a) or (b). Each answer should not exceed 600 words. 16. (a) Define the term gonads? Describe the male and the female gonads in humans. (b) What is the difference between spermatogonium and spermatocyte? and concerning events during the periods of life Page 5

6 how different is the gametogenesis in women and in men? 17. (a) Explain the different types of cleavage patterns which is determined by the amount and distribution of yolk protein in the cytoplasm and factors influencing the mitotic spindle. (b) Describe the blastula formation and blastulation. 18. (a) Describe the geometry and mechanics of teleost gastrulation and the formation of primary embryonic axes. (b) Write an essay on Activin and its receptors during gastrulation and the later phases of mesoderm development in the chick embryo. 19. (a) Describe how the epidermal derivatives are formed by the epithelium invaginating to form a cavity? (b) Describe the formation of external ear (external auditory meatus) in vertebrate development. Page 6

7 20. (a) Write a brief note on molecular nature of the embryonic induction and differentiation in vertebrates development. (b) Describe mechanisms that cause the differentiation during embryonic development. Page 7