LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PLANT BIOLOGY & PLANT BIO-TECH.
FIFTH SEMESTER – APRIL 2008
PB 5506 (GENETICS AND PLANT BREEDING)
Date : 06-05-08
Time : 1:00 - 4:00
Dept. No.
KL 22
Max. : 100 Marks
PART – A
(20 marks)
Answer all questions
I. Choose the correct answer:
(5 x 1 = 5 marks)
1. The condition in heterozygotes where the phenotype is intermediate between the two homozygotes in
called
a) co dominance
b) incomplete dominance
c) pseudodominance
d) complete dominance
2. The diploid organism which have lost a pair of chromosomes are called
a) Monoploid
b) Haploid
c) Monosomy d) Nullisomy
3. Transposable elements were discovered by
a) Barbara Mc Clintock
b) Morgan
c) Sutton
d) Boveri
4. A codon, which undergoes an alteration to specify another amono acid is called ___________ codon.
a) stop
b) Start
c) Termination
d) missense
5. The theory of inheritance of acquired characters proposed by
a) Lamarck
b) Darwin
c) Weismann
d) Stebbins
II. State whether the following statements are True or False:
(5 x 1 = 5 marks)
6. Coat color in mice is governed by multiple alleles.
7. The genic balance mechanism of sex determination was first studied in Drosophila by Bridges.
8. Excessive development of hairs on pinna of ear is due to the inheritance of
X-linked genes.
9. The CIB method for detecting lethal mutations in sex chromosomes was proposed by H.J.Muller.
10. The crosses between two unrelated pure breeding, populations are called in breeding.
III. Complete the following:
(5 x 1 = 5 marks)
11. ________________ cross is primarily used for chromosome mapping.
12. ________________ enzymes are capable of catalyzing phosphodiester bond formation.
13. The inheritance of quantitative traits is called _________________.
14. The group of nucleotides that specifies one amino acid is called ___________.
15. The term mutation used first by ________________.
IV. Answer all questions each in about 50 words:
(5 x 1 = 5 marks)
16. What is aneuplopidy?
17. Define lethal genes.
18. Write short note on Nuclease enzymes.
19. Write short note on Frame shift mutation.
20. What is heterosis?
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PART – B
Answer any five, each with 350 words only. Draw diagrams and flow charts wherever necessary:
(5 x 8 = 40 marks)
21. What is cytoplasmic inheritance? Explain with one example.
22. Briefly describe the sex determination in plants.
23. DNA as a genetic material discuss.
24. Write briefly on gene and its organization.
25. Explain the effects of chemical mutagens.
26. Give an account of super coiling of DNA.
27. Write a brief note on Darwins theory.
28. Briefly describe the procedure of pureline selection and discuss its merits and demerits.
PART – C
Answer the following, each with 1500 words only. Draw diagrams and flow charts wherever necessary:
(2 x 20 = 40 marks)
29. a) Write an essay on different types of chromosomal aberrations.
OR
b) Describe in detail on monohybrid cross and its modifications
30. a) Describe the following.
i) Klinfelters syndrome
ii) Transposable elements
OR
b)
i) Describe the quantitative inheritance with suitable examples.
ii) Give an account on Hybridization. Add a note on its significance.
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