HPSC HCS Mains Optional Paper 2009: Botany Frontier IAS
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HCS Mains-2009 BOTANY
Time: 3 Hours Maximum Marks: 150
Note: Attempt five questions in all. All questions carry equal marks. Question No. l is compulsory. Answer two questions from Part-I and two questions from Part-II. The parts of the same question must be answered together and must not, be interposed between answers to other questions.
1. Write short notes on any four of the following : (4 X 7.5 = 30)
(a) Economic importance of algae
(b) Heterosis in plants
(c) Vernalisation
(d) Role of parasexual hybridization in plant breeding
(e) Heterospory and Seed habit in Selaginella
(f) Chi-square test in plant Crossings
PART - I
2. (a)What is a bacteriophage? Discuss the Lysogenic life cycle of a typical Bacteriophage. (10)
(b) What is biological nitrogen - FIxation? Discuss the role of nitrogen - FIxers in the economy of nitrogen in nature. (10)
(c) What is the alternation of generation? Discuss the role of this in the life cycle of Pteris. (10)
3. (a) What is Black stem Rust of wheat ? Discuss the process of infection of the causal organism and its life cycle. (10)
(b) What is anomalous secondary growth in plants? Discuss the same in Dracaena. (10)
(c) Illustrate the mature sporophyte of Moss. Distinguish between spores and elaters. (10)
4. (a) Explain Flora and Vegetation. Give a brief account of the Botanical Provinces of India. (10)
(b) Discuss briefly the merits and demerits of Bentham & Hooker's system of Classification. (10)
(c) What is a Virus? Discuss infection, replication and spread, and control of TMV. (10)
PART - II
5-(a) Discuss the phenomenon of Gene Interaction with reference to Complementary and Epistatic genes. (10)
(b) How does Operon regulate the process of enzyme synthesis in Prokaryota? (10)
(c) What is the mutation? Explain Spontaneous and induced mutations and their role in plant breeding. (10)
6. (a) What is the C4 Cycle? Differentiate it from C3 Cycle. Correlate these to the structural features of plants. (10)
(b) Distinguish between Oxidative and photophosphorylation. Which is more efficient? (10)
(c) Define Totipotency. Discuss the role of plant growth hormones in plant growth and development. (10)
7. (a) Define Biodiversity. Describe 'Hot Spots' of World Biodiversity. (10)
(b) What is the 'Green House Effect'? Discuss the role of greenhouse gases in the human environment. (10)
(c) Explain the Term 'Central dogma of Molecular Biology. Briefly describe the process of transcription and translation. (10)