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AMB821S - ADVANCED MICROBIOLOGY - 2ND OPP - JAN 2023 |
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n Am I BI A u n IVER s I TY
OF SCIEnCE Ano TECHnOLOGY
FACULTY OF HEALTH, NATURAL RESOURCES AND APPLIED SCIENCES
DEPARTMENT OF NATURAL AND APPLIED SCIENCES
QUALIFICATION: BACHELOR OF SCIENCE (Hon)
QUALIFICATION CODE:
LEVEL: 8
COURSE CODE: AMB8215
SESSION: FEBRUARY2023
TIME: 3 HOURS
COURSE NAME: ADVANCED MICROBIOLOGY
PAPER: THEORY
MARKS: 100
SECOND OPPORTUNITY/SUPPLEMENTARY
EXAMINER(S) DR MUNYARADZI ZIVUKU
EXAMINATIONS QUESTION PAPER
MODERATOR: PROF JANE MISIHAIRABGWI
Instructions
1. Answer all questions
2. Answer the questions in the booklet provided
3. Write clearly and neatly
4. All written work MUSTbe done in blue or black ink
5. Mark all answers clearly with their respective question numbers
THIS QUESTION PAPER CONSISTS OF 4 PAGES
(INCLUDING THIS FRONT PAGE)
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SECTION A (40 MARKS)
QUESTION 1 {20)
You wish to determine the number of bacteria in an actively growing broth culture off. coli.
To do this you remove 1.0 ml of the culture from the flask and dilute this in 9 ml of nutrient
broth to obtain 10-1 dilution. You then serially dilute the sample further until you obtain a
range of dilutions between 10-2 and 10-6. From each dilution you then spread plate 0.1 ml of
suspension onto the nutrient agar and incubate overnight. The next morning you obtain the
following results.
Dilution
Neat
10-1
10-2
10-3
10-4
10-S
10-6
Colonies on plate
Too many to count
Too many to count
Too many to count
280
27
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0
1.1 Determine how many bacterial colonies per ml there were in the original sample taken
from overnight culture. Show your working.
(4)
1.2 You adjust the density of the cell suspension so that there are 1 x10 6 bacteria per ml
in broth and add 1 ml of this to a new culture flask. Assuming exponential growth and
a doubling time of 30 minutes, how many bacteria will be in the flask after 5 hours?
Show your working.
(4)
1.3 Briefly define the term coliforms and their role in the diagnostics of waste water
treatment.
(4)
1.4 The occurrence of plasmids in microorganism is a necessary evil. Discuss the
statement.
(8)
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QUESTION 2 (20}
2.1 Briefly outline five factors leading to the emerging of infectious diseases in the 21st
century.
{10)
2.2 The basic reproductive number, (Ro), defines the mean number of individuals directly
infected by an infectious case through the total infectious period, when introduced to
a susceptible population, and is given by the equation
• Ro= p. C. d
Define the terms p, c, d and how they can be used to combat infections such STI. (4)
2.3 Briefly evaluate the implication of Roas used in epidemiology.
(6)
QUESTION 3 (20}
You have been hired as a consultant for a large multi-corporation specializing in
pharmaceutical products to advise how they can set up a plant to produce an
antibiotic for the local farmers.
3.1 Considering that the human resources and financial aspects are taken care of by the
organization, what technical information would you advise the management
requirements to start the production of the antibiotics? Justify your selection of the
requirements needed for fermentation.
(5)
3.2 Some board of directors for the new company may be interested in procurement of a
large fermenter but are still not sure whether to settle for a batch fermenter or
continuous fermenter. Briefly discuss why it will be ideal to purchase a batch
fermenter as opposed to a continuous fermenter to produce the antibiotic.
(5)
3.3 You are also asked to write a short report of how the antibiotic will be produced in
the new proposed plant. Briefly outline how the antibiotic will be produced in your
proposed fermentation vat.
(10)
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QUESTION 4 [20 MARKS]
4.1 Discuss the impact of pollution in the environment and human beings.
(6)
4.2 Evaluate the application of genetically engineered strains of microorganism and
plants in the clean-up of environments contaminated with pollutants.
(6)
4.3 Briefly describe the principle underlying the Disk Diffusion Method of antibiotic
sensitivity testing and how it differs from Kirby Baeur Method.
(8)
QUESTION 5 {20}
5.1 Briefly explain the conditions necessary for a pathogen to cause disease.
(4)
5.2 Outline the pathogenic properties of virus.
(5)
5.3 With the aid of an annotated diagram, discuss the role of antigen presenting cell in
cell mediated immunity following the entry of an infectious agent in the human body
and its eventual removal from the body.
(10)
END OF QUESTION PAPER
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