faculty of science department of biotechnology june examination

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FACULTY OF SCIENCE

DEPARTMENT OF BIOTECHNOLOGY

NATIONAL DIPLOMA
:
BIOTECHNOLOGY
,
FOOD TECHNOLOGY

MODULE
MCB1AM1

MICROBIOLOGY 1

CAMPUS
DFC

JUNE EXAMINATION

DATE: 13/06/2008
SESSION: 9:00

11:00

ASSESSOR
MR. K. MACLEAN

INTERNAL MODERATO
R
MR. F.E VAN ZYL

DURATION
:
2 HOURS
MARKS
:
120

NUMBER OF PAGES
:
8
PAGES

INSTRUCTIONS:
CALCULATORS ARE PERMITTED (ONLY ONE PER STUDENT)
.

THIS QUESTION PAPER MUST BE RETURNED WITH SCRIPT
.

REQUIREMENTS:
ANSWER SCRIPT

UJ MULTIPLE CHOICE ANSWER SHEET

/2...
MICROBIOLOGY 1 MCB1AM1 JUNE 2008
- 2 -

/3…

INSTRUCTIONS TO STUDENTS
:

1.
ANSWER ALL THE QUESTIONS
.

2.
RETURN EXAMINATION PAPER WITH SCRIPT
.

3.
ANSWER SECTION A ON UJ MULTIPLE CHOICE ANSWER SHEET
.

4.
ANSWER SECTION B ON THE ANSWER SHEET PROVIDED, DETACH AND

HAND IN WITH YOUR SCRIPT
.

SECTION A

Answer the following questions on the UJ Multiple Choice Answer Sheet provided. Before

filling in the
required details on your answer sheet read the instructions carefully and make

sure that you fill in your choices correctly.

QUESTION 1

1.
1
Cellular micro organisms are found in the following domain /s of life
:

a.
Bacteria

b.
Eucarya

c.
Archaea

d.
Only (a)

e.
All of (a)
, (
b) and (c) are correct

1.2
To observe two adjacent objects with the light microscope clear from

one another as separate
entities is called:

a.
magnification

b.
resolution

c.
numerical aperture

d.
contrast

1.3
The
cyanobacteria
can photosynthesise
:

a.
True

b.
False

1.4
The germ theory of biogenesis was opposed by:

a.
Galileo

b.
Salk

c.
Redi

d.
Spallanzani

e.
Pasteur

1
.5
Organisms which use CO2 and light as a source of carbon and energy

are called:

a.
Autotrophs

b.
Prototroph’s

c.
Photoorganoheterotrophy

d.
Chemolithoautotrophy

e.
(a) and (b)
MICROBIOLOGY 1 MCB1AM1 JUNE 2008
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/4…

1.6
Which of the following is not a major class of growth factors?

a.
amino acids

b.
purines and pyrimidines

c.
vitamins

d.
All of the above are major classes of growth factors

1.7
Small organic molecules that usually make up part of enzyme co
-

factors are called:

a.
Vitamins

b.
Proteins

c.
Carbohydrates

d.
None of the above is correct

1.8
The rate of diffusion across a semi
-
permeable membrane is greatly

increased by using carrier proteins such as:

a.
dehydrogenases

b.
liases

c.
permeases

d.
lactose

1.9
Passive transport is the transport of solute molecules to:

a.
higher concentrations

b.
against a concentration gradient

c.
lower concentration

d.
a and b

1.10
Agar is a sulfated polymer composed mainly of:

a.
D-
galactose

b.
L-
galactose

c.
D-
glucuronic acid

d.
all of the above

1.11
Peptones are _________ hydrolysates:

a.
lipid

b.
protein

c.
carbohydrate

d.
amino acid

1.12
Agar is usually extracted from:

a.
seaweed

b.
brown algae

c.
green algae

d.
red algae
MICROBIOLOGY 1 MCB1AM1 JUNE 2008
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/5…

1.13
Microbial growth can be terminated by controlling the
:

a.
exponential phase

b.
lag phase

c.
death phase

d.
stati
onary phase

e.
microbial growth curve in any way

1.14
The chemical used to clean the microscope lenses is called:

a.
Xylene

b.
Ether

c.
Weak hydrochloric acid

d.
Ethanol

1.15
One should use a plate which yields between ___________ and

__________ colonies for a total mesophillic bacterial count.

a.
35-300

b.
0-100

c.
25-250

d.
40-300

1.16
The inhibition of microorganisms is caused by:

a.
sterilisation

b.
disinfection

c.
sanitation

d.
pasteurization

e.
None of the above

1.17
John Tyndall contributed towards a technique today known as:

a.
gram staining

b.
autoclaving

c.
fractional sterilisation

d.
serial dilution

1.18
Which of the following is not a characteristic of active transport?

a.
saturable rate of uptake

b.
requires an expenditure of metabolic energy

c.
can transport materials against a concentration gradient

d.
All of the above are characteristics of active transport

1.19
An autoclave generally sterilise at:

a.
121ºC

b.
100ºC

c.
90ºC

d.
80ºC
MICROBIOLOGY 1 MCB1AM1 JUNE 2008
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/6…

1.20
An/example(s) of photolithotrophic autotrophy microorganisms is/are:

a.
algae

b.
purple sulfer bacteria

c.
green sulfur bacteria

d.
all of the above

1.21
An/example(s) of photoorganotrophic heterotrophy microorganisms

is/are:

a.
protozoa

b.
fungi

c.
most non
-
photosynthetic bacteria

d.
None of the above

1.22
Microbial cell mass can be measured with the aid of a:

a.
Coulter counter

b.
Petroff
-
Hausser Counting Chamber

c.
Spectrophotometer

d.
Microscope

1.23
Ultra high sterilisation takes place at:

a.
150ºC/1
-
3 hours

b.
100ºC/1
-
3 hours

c.
150ºC/1
-
3 seconds

d.
100ºC/1
-
3 hours

1.24
Heterotrophs usually obtain preformed, partially reduced organic

molecules from other organisms:

a.
True

b.
False

1.25
Bacterial cells in an hypotonic solution will:

a.
lyse

b.
plasmotyse

c.
remain unchanged

d.
None of the above is correct.

1.26
Lipopolysaccharide which is found in the outer membrane of gram
-

negative bacteria, is also known as:

a.
teichoic acid

b.
exotoxin

c.
endotoxin

d.
murein

1.27
Which of the following is a function of molecular chaperones?

a.
Ensure proper folding of nascent polypeptide chains

b.
Maintain secretory proteins in an export
-
competent state

c.
Both (a) and (b) are correct

d.
Neither (a) nor (b) is correct
MICROBIOLOGY 1 MCB1AM1 JUNE 2008
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/7…

1.28
The bacteria which stains purple with the Gram staining technique are

Gram:

a.
positive

b.
strictly negative

c.
negative or positive

d.
Does not stain with the gram stain technique due to its cell wall

1.29
Which of the following organisms are associated with the roots of

plants?

a.
Nitrobacter

b.
Nitrosomonas

c.
Saccharomyces

d.
Both (a) and (b)

1.30
W
hich of the following is not true of bacterial plasmids?

a.
They can exist and replicate independently

b.
They are required for host growth

c.
They may carry genes for drug resistance

d.
They may carry genes that give the bacterium new useful metabolic

activities

[30]

QUESTION 2

2.1
With the aid of a flow diagram explain the life cycle of
Entamoeba

histolytica
.
From the life cycle, indicate five ways how this parasite can

be controlled
(20
)

2.2
Describe the significance of lactose positive and negative bacteria on

MacConkey agar
.
(5
)

[25
]

QUESTION 3

A total of 26 students each require the following culture media:

3.1
T
en test tubes each with 10 millilitres nutrient broth.

3.2
Fifteen nutrient agar slants, each containing 7 millilitres of agar.

3.3
Twenty three agar plates, each containing 25 millilitres of agar

The instructions on the nutrient broth container indicates 22 grams per litre and

the nutrient agar 26 gram per litre of distilled water.

How much nutrient agar and broth will 26 students need?

Show
clear, neat and tidy
explanatory calculations
.
[1
0]
MICROBIOLOGY 1 MCB1AM1 JUNE 2008
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/8…

QUESTION 4

4.1
Draw a labelled diagram of a typical prokaryotic cell and give the

functions of each organelle.
(10)

4.1
With the aid of an illustration explain how you would perform a serial

dilution
up to a 1/1000 to determine the total CFU per millilitre of a

water sample. Assume you obtain 50 colonies on the second dilution

and you used the spread plate technique.
(10)

[2
0]

QUESTION 5

5.1
Name and describe 5 (five) factors which influence the effectiveness of

an antimicrobial agent.
(10)

5.2
With the aid of a graph explain the bacterial growth curve
.
(10)

[20]

(Section B to follow on next page)
MICROBIOLOGY 1 MCB1AM1 JUNE 2008
- 8 -

SECTION B

Detach and hand in together with your answer book

QUESTION 6

INITIALS: ______________ SURNAME: ___
_______________________

COURSE: _________________________ STUDENT NO: _______________

Answer the following questions in the space provided and hand in together with

your examination script.

A)
Name the stains involved with the endospore staining technique
:

________________________________________________________

________________________________________________________

________________________________________________________
(2
)

B)
Describe how a culture can be lyophilised.

________________________________________________________

________________________________________________________

________________________________________________________
(3)

C)
Name two medical important parasites and indicate the disease

caused by each.

________________________________________________________

________________________________________________________

________________________________________________________
(2
)

D)
Name and explain
t
he three types of reactions caused by bacterial

growth on blood agar
.

________________________________________________________

________________________________________________________

________________________________________________________
(3
)

E)
Briefly differentiate between
disinfection,
sanitation and sterilisation.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________
(4)

F)
What is “biotechnology” for the biotechnologists and “food technology”

for the food technologists?

________________________________________________________

________________________________________________________
(1)

[30]