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Soil Biology And Biochemistry Question Paper

Soil Biology And Biochemistry

Course:Master Of Science In Agricultural Education

Institution: Kenyatta University question papers

Exam Year:2010

KENYATTA UNIVERSITY
UNIVERSITY EXAMINATIONS 2010/2011
INSTITUTIONAL BASED PROGRAMME (IBP) AUGUST 2010 SESSION
EXAMINATION FOR THE DEGREE OF MASTER OF SCIENCE
KRM 501: SOIL BIOLOGY AND BIOCHEMISTRY
DATE: Tuesday 28th December 2010 TIME: 9.00a.m -12.00p.m
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INSTRUCTIONS
Answer Question ONE and any other THREE.
1. (a) Name the bacteria which oxidize reduced sulfur compounds to sulfate in soil. Show by equation how that is achieved. (6 marks)

(b) Before the soil at Yala swamp was reclaimed the pH was 6.5. After a year, its pH had dropped to 5.0. Explain the cause of the pH drop. (4 marks)

(c) Explain the following terms:
(i) chemoautotrophs
(ii) photoautotrophs
(iii) nitrogen
(iv) recalcitrant molecule
(v) fermentation (10 marks)

(d) Explain photosynthesis by phototrophic bacteria. How does it differ from photosynthesis by higher plants?

(e) What is the role of bacteroids in N fixation? (5 marks)

(f) Explain how microorganisms obtain energy for their metabolic activities in soil.(2 marks)

2. Protein is an important organic substrate. Discuss its biodegradation and the main end product at each step of degradation. (15 marks)

3. Distinguish between biodegradation of DDt and chitin in soil. Discuss the advantages of biodegradation to environment and man. (10 marks)

4. With examples name two types of hydrocarbon and explain why they are not easily biodegraded in soil. (15 marks)