Aab 3121: Agricultural Microbiology Question Paper
Aab 3121: Agricultural Microbiology
Course:Food Security,Horticulture And Animal Science
Institution: Jaramogi Oginga Odinga University Of Science And Technology question papers
Exam Year:2014
JARAMOGIOGINGAODINGAUNIVERSITYOFSCIENCEANDTECHNOLOGY
SCHOOL OFAGRICULTURAL AND FOODSCIENCES
FIRST YEAR SECOND SEMESTEREXAMINATIONSFORTHEDEGREEOFBACHELO
ROFSCIENCEINFOODSECURITY, HORTICULTURE AND ANIMAL
SCIENCE2013/2014ACADEMICYEAR
AAB 3121: AGRICULTURAL MICROBIOLOGY
DATE: TIME: 0
Instructions:
1. This paper consists of TWO sections, A and B.
2. Answer ALL questions from section A and any TWO from section B.
3. Write all answers in the booklet provided.
SECTION A[30MARKS]
Answer ALL questions in this section
1. a) Define the following terminologies:
i)Mycorrhizae. [1 mark]
ii)Chemoheterotrophy. [1 mark]
iii)Archae. [1 mark]
iv)Pasteurization. [1 mark]
b) Explain the differences between:
i) Simple stain and differential stain. [2 marks]
ii) Catabolism and anabolism. [2 marks]
iii) Osmotolerant and halophilic bacteria. [2 marks]
2. a) Describe the mode of action of microbes or microbial metabolites as bio-pesticides?[5 marks]
b) Define fermentation and describe its relationship with the overall-energy production processes. [5 marks]
3. a) Differentiate between Gram-positive and Gram-negative bacterial cell wall highlighting the structurally component responsible for differences in virulence and response to penicillin and lysozyme. [5 marks]
b) Briefly discuss the concept of microbial bio-fertilizers in agricultural production. [5 marks]
SECTION B [40 MARKS)
Answer ANY TWO questions from this section
4. a) With help of an illustration, discuss the microbial growth highlighting what occurs at the
different phases of growth and their important metabolites [12 marks]
b) Describe the main categories of microorganisms on the basis of optimum temperature
and the corresponding environment in which a representative might thrive [8 marks]
5. Atmospheric nitrogen gas (N2) is unavailable to plants. Plants therefore depend on various
types of nitrogen-fixing bacteria to take up nitrogen gas and make it available to them as
some form of organic nitrogen. Discuss nitrogen cycle highlighting the role of
microorganisms in each step. [20 marks]
6. Microorganisms are important in the food industry for production of fermented foods and
beverages. Using examples, discuss the above statement starting clearly the roles of
microorganism in the production of fermented foods and beverages. [20 Marks]
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