VM 132 Probation 2022

SOKOINE UNIVERSITY OF AGRICULTURE

COLLEGE OF VETERINARY MEDICINE AND BIOMEDICAL SCIENCES

PROBATION/FIRST SITTING EXAMINATION FOR 1ST YEAR BSc ANIMAL SCIENCE

DATE:

TIME:

INSTRUCTIONS: ATTEMPT ALL QUESTIONS
Use well labeled diagrams where necessary

VENUE:

 

QUESTION ONE
1. A) Write TRUE for correct statement and FALSE for incorrect statement (10 marks)

a) Escherichia coli is a gram-negative bacterium that ferments lactose…………
b) Gram-positive bacteria possess lipopolysaccharides for endotoxins production…………
c) Bacteria growth is measured as the increase in cell number…………….
d) Halophiles grow well at the pH range of 6.5 to 7.5……………………….
e) Majority of the cultured bacteria are mesophiles………………………
f) Sterilization refers to the reduction of unwanted microorganism…………
g) Nutrient agar is an example of the enriched media……………
h) Gram stain is an example of a complex stain…………………
i) Infection is the degree of ability of an organism to cause disease and damage to its host…….
j) Bacillus anthracis is an example of spore forming bacteria…………………….

2. B) Complete the following statement with a correct term or word (10marks)
a) The process of determining the bacteria cell numbers from a sample is known as ……..
b) Method of diluting a stock solution where concentration decreases by the same quantity in each successive step is known as……………
c) Bacteria that require less amount of oxygen are termed as…………………
d) Bacteria that stain positive to Ziehl-Neelsen stain are collectively known as………
e) A strain of E. coli that produce hemorrhagic diarrhea in human and calves………………

 

QUESTION TWO

2. A) Bacteria growth is affected by several factors, one of them being gaseous concentration; with examples classify bacteria according to the gaseous requirement for growth.
(8 marks)

2.B) You are summoned by the Tanzania Milk Board to Assist them evaluating the quality of milk sold by Umoja Milk Factory is unfit for public consumption. After performing a viable bacterial count of two milk samples (one from Pasteurized milk and another from long life milk) you obtained the following:
a) For pasteurized milk you counted 170 colonies of Thermoduric E. coli on a plate containing a 1/1,000,000 dilution of the original 1ml of sample
b) For long life milk you counted 65 colonies of Thermoduric E. coli on plate containing 1/1000 dilution of the 1ml of the sample
Questions
I. Calculate the CFU/ml of pasteurized milk from data given in (a) above (5marks)
II. Calculate the CFU/ml of long-life milk from data given in (b) above (5marks)
III. How would you advise the Tanzania Milk Board regarding the quality of both pasteurized and long-life milk from Umoja milk factory? (2marks)
NOTE: Show all your calculations clearly
Hints
Permissible number of bacteria flora in pasteurized milk is 5X 104 cfu/ml
Permissible number of bacteria flora in long life milk is 10 cfu/ml

 

QUESTION THREE
a) Provide reasons to support each of the following schools of thought about viruses
(i) Viruses are living pathogens (TWO reasons) 4 marks
(ii) Viruses are non-living pathogens (any THREE reasons) 6 marks
b) State any SIX criteria used in viral classification (9 marks)
c) Mention sequentially the SIX steps of viral replication cycle (6 marks)

 

QUESTION FOUR

PART A: Provide the most appropriate answer to describe each of the following phrases (15 Marks)

a) List any two (2) salient features/characteristics of fungi ……………. and ……………..
b) The sexual form of a fungus ………………………….
c) A chain of elongated budding cells that have failed to detach (not true hyphae) …………
d) A symbiotic association between fungi and algae …………………………….
e) A thick-walled resting spore of fungi produced to survive unfavourable conditions ………
f) Fungi that lack a known sexual stage ……………………………..
g) Fungi that can exist in the form of both mould and yeast …………………………….
h) Mention any two (2) modes/methods of asexual reproduction in fungi ……… and ………
i) Most of fungi grow aerobically on ordinally culture media at temperature ranging of ……..
j) Mention any two (2) examples of commonly Mycotoxins found in contaminated foodstuffs ……………….. and …………………..
k) All fungi require organic nutrients for their energy source. The methods of getting these nutrients categorize fungi into different groups, for example fungi may grow as parasite. List two (2) other forms of getting nutrients in fungi ………….. and ……………….

PART B: Write TRUE for correct statement and FALSE for incorrect ones (10 Marks)

a) Mycotoxins are toxic compounds produced by moulds, yeasts and mushrooms …………
b) Aspergillus spp. and Penicillium spp. produces mobile zoospores that move by means of flagella …………
c) Microsporidia are a group of spore-forming unicellular fungi and possess flagella ………
d) Saccharomyces cerevisiae is unicellular yeast and replicate by binary fission …………….
e) Rhizopus stolonifer produces coenocytic mycelium and reproduces by asexual spores …
f) Mycelium grow by elongation of their tips and reproduce by budding ………………
g) Budding and binary fission are sexual method of reproduction in yeasts ……………..
h) Mucor and Rhizomucor lack Mitochondria but instead contain hydrogenosomes ……….
i) Aflatoxin is a mycotoxin produced by Candida spp. and grows mostly on peanut crops …
j) Neocallimastigomycetes are found in digestive tracts of ruminants and they have septate hyphae ……………..

 

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