N9 012'993



BOTANY

Paper II
ITime AU{)wed Three Hours I ,IMaximum Marks: 2001
INSTRUCTIONS
Candidates should atte11l:pt questions 1 5
which are compulsory, and any THREE ofthe

remaining questions, selecting at least ONE
question from 'each Section.
All questions carry equal marks.
Marks alioHed to parts ofa question are

indicated against each.
Answers must be written in ENGLISH only.
Suitable diagrams may be drawn,-wherever

required.
SECTION A
1. Distinguish between any eight of the following:
n and 2n 'chromosome numbers. (b)Degree of freedom and Probability Meiotic and Somatic pairiqg
(d)Transition and Transversion
(e)Nucleolus and Nucleosome
Plastogenes and Holandric genes
Coupling and Repulsion
(h)Cytoplasmic inheritance and Dauermodification
(i)RFLP and RAPD
(j)cis and trans conditions
2. Despite the fact that DNA sequences do not arise de-nouo. in living their number increased during ·evolution. Name and describe. the most probable mechanism responsible for this Increase. 10
Discuss how discovery of infectious. proteins brought a change in the concept' of inheritance. 10
Using plants with genomic constitution "APi' and "BB", explain how you· can raise intervarietal, interspecific and intergeneric polyploids.10
What are the problems of distant hybridisation and what strategies would you suggest In overcoming the same 10
Illustrate· the fate of two homologous chromosomes that have undergone unilateral crossIng over. 10
How has the exception to one of the Mendelian principles helped in bettcr understanding of the precise location of Mendelian factors? 10
What are designer crops? Explain how these-can be developed. 10
What will be the fate of a cell line that lacks guide RNA? 10

Describe two phenomena that have led to the formation of multigerte families. 10
Name and describe the phenomenon that can work as a!1 antidote to the gene and ensure that a good allelic cOO1Qination does not break down. 10
Although Y chromosome of Drosophila IS heterochromatic and remains "inactive", lack of Y chromosome results in sterile males. How does the mere presence of "inactive Y" chromosome make them fertile 10
Micropropagatibn technique IS widely used in increasing the productivity of vegetatively propagated crops. Explain. 10
SECTION B
5. Explain any eight of the following:
Isoenzymes

(b)RUBISCO·

(c)Phytochelatins

(d)Brassinosteroids

(e)Chloroplast dimorphism

(f)Fo- FI ATPase

Nutrient Loading

(h)Bioremediation

(i)Florigen

(j)Temperature inversion

Discuss the role of carrier proteins in ion uptake by plants. 15_
Explain the carbon fixation pathway in plants where the activities of two enzymes are temporally separated. What is the ecological significanc'e of that pathway, 15

What are the causal factors that are associated with sympto;ms such as shortened internodes, death of shoot apices and intraveinal chlorosis in crop plants? 10
Mention the biotechnological approaches used for deJaying ripening of fruits such as tomatoes. 15
(b)Abscisic·acid is a stress hormone. Discuss. 15
Comment on the following': 10
Transpiration a necessary evil.
Photorespiration -useful if not essential process.
Deep water bodies in alpine environment never completely freeze to solid. Explain. 10
(b)Explain the role of hydrological cycle In regulating the climate. 10
What are the criteria used in the assessment of conservation status of species? Cite at least onc example belonging to each of the threatened categories of plants. 10
(d)"The length of grazing food chain is finite and
terminates at the third trophic level, on an
average, in a community." Explain. 10

B-JGT-K-CPB 5