LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PLANT BIOLOGY & PLANT BIO-TECH.
FIFTH SEMESTER – April 2009
PB 5506 – GENETICS AND PLANT BREEDING
Date & Time: 27/04/2009 / 1:00 – 4:00 Dept. No. Max. : 100 Marks
PART – A
- CHOOSE THE CORRECT ANSWER: 5 x 1 = 5
- Eye colour in Drosophila is an Example of
- Multiple allele Lethal gene c. Epistatic gene d. Supplementary gene
- This is formed when breaks occur in 2 chromosomes, simultaneously, & the broken chromosomes rejoin in a new manner,
- Inversion Translocation c. Replication d. Duplication
- The smallest unit of recombination is
- Muton cistron c. Recon d. operon
- Pureline selection was 1st developed by
- Nilsson Bruce c. Shull d. Johannsen
- Translation occurs at the
- Ribosomes Mesosomes c. Dictyosomes d.Glyoxysomes
- STATE WHETHER THE FOLLOWING STATEMENTS ARE TRUE OR FALSE: 5 x 1 = 5
- Plasma genes are present in the cytoplasm & transmit characters from one generation to another.
- Genetic exchange in Eukaryotes occurs by Transformation Transduction & conjugation.
- Klienfelter’s syndrome is genotypically and phenotypically male but bears many female characters.
- Nonsense codons are those for which there are no aminoacids.
- Down’s syndrome is also known as Mongolism.
- COMPLETE THE FOLLOWING: 5 x 1 = 5
- ____________ is a cluster of genes coding for a series of enzymes that work in an integrated biochemical pathway.
- In Transcription the information in the DNA is transferred to ______________.
- The smallest element, alteration of which can be effective in causing mutation is called ___________.
- The basic unit of DNA molecule is _____________.
- Post replicative repair mechanism, that may or may not involve rec A is termed _________ repair.
- ANSWER ALL, EACH IN ABOUT 50 WORDS: 5 x 1 = 5
- What are Alleles.
- Mention the law of Independent Assortment
- Define Heterosis.
- What are Lethel genes.
- Define Codominance.
PART – B
ANSWER ANY 5, EACH WITHIN 350 WORDS ONLY: 5 x 8 = 40 Marks
- Write down the conservative method of Replication.
- Explain point Mutation.
- Explain Darwinism.
- What is Mismatch repair.
- Explain clonal selection.
- Write down the centres of diversity and the origin of cultivated plants.
- Explain sex determination in plants.
- Write about Quantitative Inheritance.
PART – C
ANSWER THE FOLLOWING EACH IN 1500 WORDS: 2 x 20 = 40 Marks
- Describe the molecular structure of DNA.
Write about DNA repair mechanisms.
- Explain the selection Methods in Plant Breeding – Mass and Pure line selection.
Write an essay on chromosomal aberrations.
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