LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PLANT BIOLOGY & BIOTECHNOLOGY
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FOURTH SEMESTER – APRIL 2006
PB 4500 – CYTOGENETICS AND PLANT BREEDING
(Also equivalent to PBB 506)
Date & Time : 27-04-2006/9.00-12.00 Dept. No. Max. : 100 Marks
Part – A
Answer the following questions: (20 marks)
I Choose the best answer (5 x 1 = 5)
- The primary component of plant cell wall is
- Pectin b. Lignin c. Cellulose d. Hemicellulose
- Flower colour of Mirabilis jalapa is the best example for
- Incomplete dominance b. Co-dominance c. Lethal genes d. Epistasis
- The initial amino acid in prokaryotic protein biosynthesis is
- Methionine b. Formylmethionine c. Glycine d. Phenylalanine
- Raphano brassica is an example for
- Haploid b. Diploid c. Amphidiploid d. Tetraploid
- Which one of the following is not involved in emasculation
- Scissors b. Hot water c. Ethanol d. Acid
II State whether the following statements are true or false (5 x 1 = 5)
- Mitochondria help in the respiration process.
- Lethal genes are not expressed in homozygous condition.
- The basic unit of a gene responsible for mutation is cistron.
- Acrydine dye induces frame shift mutation.
- ICRISAT is located at New Delhi.
III Complete the following (5 x 1 = 5)
- Crossing over occurs during the ————- stage of meiosis.
- Quantitative inheritance is influenced by —————– genes and ————–.
- Chromosomal proteins are ——– and —————.
- Thymine dimerization is caused due to ————-.
- Selection method in vegetatively propagated plants is known as ————–.
IV Answer the following within 50 words each. (5 x 1 = 5)
- Comment on cell theory
- Write notes on codominance.
- Define splicing.
- What is transversion?
- What are centres of origin?
Part – B
Answer any FIVE of the following not exceeding 350 words each. (5 x 8 = 40)
- Explain the ultra structure of chloroplast.
- Describe chromosomal methods of sex determination.
- Write an account of cytoplasmic inheritance in Mirabilis.
- Enumerate the properties of genetic code.
- Explain the mechanism of transcription process.
- Give an account of the lac operon model.
- Write notes on DNA repair mechanism.
- Differentiate mass and pure line selection.
Part – C
Answer the following not exceeding 1500 words each. (2 x 20 = 40)
- (a). Draw neatly labelled diagrams of meiotic stages with footnotes.
Or
(b). Write an essay on multiple alleles.
- (a) Describe the variations caused due to chromosomal abnormalities.
Or
(b) Write detailed notes on hybridization techniques.