LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

   B.Sc. DEGREE EXAMINATION – PLANT BIOLOGY & PLANT BIO-TECH.

FIFTH SEMESTER – NOVEMBER 2010

PB 5516/PB 5510/PB 5506 – GENETICS, PLANT BREEDING AND EVOLUTION

 

 

 

Date : 01-11-10                     Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

PART – A (20 marks)

      Answer ALL questions.

 

1. I. Choose the correct answer             (5×1=5)

 

1. Cross  of  F₁  individual with the recessive parent is known as a cross.
2. a)  test            b) back                c) dihybrid                       d) Monohybrid
3. Which of the following are the stop codons?
4. a) UAA ,UGA , UAG  b)UCC, UAA,UCA  c)UAA, UAG,UCA  d) UAA, UAC, UCA
5. The genetic condition of   individuals with Klienfelter’s syndrome is
6. a) XYY           b) XXX               c) XXY                  d) XY
7. The term heterosis was coined by
8. a) Bruce         b) Shull               c) Nilsson             d) Johannsen
9. Charles Darwin went on a voyage on a ship named
10. a) HMS Eagle b) HMS Beagle         c) HMS Bugle        d) HMS Titanic

 

1. State whether the following statements are True or False (5×1=5)

 

1. Cytoplasmic male sterility in maize is attributed to the female parent.
2. The start codon AUG codes for Methionine.
3. Transition is a base change that changes the Pyrimidine – Purine orientation.
4. Heterosis results from the crossing of genetically unlike organisms.
5. Mutation does not play a part in evolution.

III. Complete the following                                                                                              (5×1=5 )

 

11. Lethal genes in plants  was first reported in __________.
12. Negative superhelicity in E.coli DNA is brought  about  by the enzyme ____
13. ___________   coined  the term mutation.
14. The progeny of a single cross- pollinated plant obtained by selfing is  called

_____________.

 

15. Inorganic evolution explains the changes that take place in _________.

 

1. Answer the following, each within 50 words only                                    (5×1=5)

 

16. Define an Allele
17. What is Genetic code?
18. Write about Point mutation.
19. Write short notes on Emasculation.
20. What is Speciation?

 

PART – B

 

Answer the following, each answer within 350 words . Draw diagrams wherever necessary.

 

(5X7=35marks)

 

21. a) Explain the second law of Mendel using a dihybrid cross.

(OR)

1. b) With a suitable example, explain Incomplete dominance in plants.

 

22. a) How is the hnRNA post transcriptionaly modified into a homogenous mRNA?

(OR)

1. b) Explain regulation of gene expression in coli.

 

23. a) What is polyploidy ? Briefly explain auto polyploidy and allopolyploidy.

(OR)

1. b) Explain the different types of chromosomal aberrations.

 

24. a) List out the positive and negative effects of heterosis.

(OR)

1. b) What are the various steps involved in hybridization procedure to obtain F1 generation?

 

25. a) Discuss the theory of natural selection.

(OR)

1. b) Critically comment on Neo-Lamarckism.

 

 

PART – C

 

Answer any three of the following, each answer within 1200  words .

Draw diagrams wherever necessary.                                                                             (3×15=45marks)

 

26. What is polygenic inheritance ? With the help of  a  Punnet square explain the

inheritance of kernel colour in wheat.

27. Enumerate the process of replication of DNA with suitable diagrams.
28. Explain in detail the different light –independent DNA repair mechanisms.
29. Discuss the methods of mass and pure line selection.
30. Write an essay on mutation theory and synthetic theory.

 

 

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