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BIO701S - BIOTECHNOLOGY - 2ND OPP - JAN 2023 |
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nAmlBIA unlVERSITY
OF SCIEn CE AnD TECHn
FACULTYOF HEALTH, NATURAL RESOURCESAND APPLIED SCIENCES
DEPARTMENT OF NATURAL AND APPLIED SCIENCES
QUALIFICATION : BACHELOR OF SCIENCE
QUALIFICATION CODE: 07BSC
LEVEL: 7
COURSE CODE: BIO701S
COURSE NAME: BIOTECHNOLOGY
DATE: JANUARY 2023
DURATION: 3 HOURS
MARKS: 100
SECOND OPPORTUNITY/SUPPLIMENTARY EXAMINATION QUESTION PAPER
EXAMINER(S) DR NORMAN MUZHINJI
MODERATOR: DR. JEAN D. UZABAKIRIHO
INSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly.
THIS EXAMINATION PAPER CONSISTS OF 7 PAGES (Excluding this front page)
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Section A: Multiple choice questions (15 marks)
1. If mRNA is complementary to the DNA template strand and the DNA template stand is
complementary to the DNA non-template strand, why are base sequences of mRNA and
the DNA non-template strand not identical? Could they ever be?
A. No, they cannot be identical because the T nucleotide in DNA is replaced with U
nucleotide in RNA and AUG is the start codon.
B. No, they cannot be identical because the T nucleotide in RNA is replaced with U
nucleotide in DNA.
C. They can be identical if methylation of the U nucleotide in RNA occurs and gives T
nucleotide.
D. They can be identical if de-methylation ofthe U nucleotide in RNA occurs and gives T
nucleotide.
2. In gel electrophoresis of DNA, the different bands in the final gel separate because the
DNA molecules
A. Are from different organisms
B. Have different lengths
C. Have different nucleotide compositions
D. Have different genes
3. The goal of a PCRreaction is to
A. Separate DNA based on fragment size
B. Determine a DNA profile
C. Produce copies of a targeted DNA region(s)
D. None of these answers
E. Sequence a DNA template region(s)
4. Which statement defines cloning?
A Making offspring identical to one parent.
B Producing identical plants and animals by natural or artificial means.
C Producing genetically identical copies of an individual, cell or gene.
D Splitting embryos to make twins.
5. A researcher is performing PCRto amplify a sample of DNA. Unfortunately, he forgot to
add the DNA primer prior to starting the experiment. Which of the following results is
he most likely to observe?
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A. The reaction will work, but at a significantly slower rate
B. The reaction will work, but the product will contain many undesired mutations
C. The reaction will be completely unsuccessful
D. The reaction will work, but amplify a region that was not his target
6. Polymerase chain reaction {PCR)employs a heat-stable polymerase, such as Taq
polymerase, to assemble the amplified strand of DNA. Which of the following best
describes why heat-stable polymerases are ideal for PCR?
A. PCRrequires thermal cycling, and heat-stable polymerases can be inactivated
when they are not needed during the low temperature phases.
B. Heat-stable polymerase cannot break the double-stranded DNA unless the
temperature is very high, thus requiring heat-stable polymerases
C. The interaction between bivalent cations and polymerases is most efficient during
high temperature phases, thus requiring heat-stable polymerase
D. PCRrequires thermal cycling, and heat-stable polymerases will neither denature
nor lose efficacy in DNA synthesis during the high-temperature cycle.
E. Heat-stable polymerases are typically much cheaper than normal polymerases
and are therefore more suited to large scale laboratory amplification of DNA
7. Why are yeast cells frequently used as hosts for cloning a gene for production of human
protein?
A. They easily form colonies
B. They can remove exons from mRNA
C. They do not have plasmids
D. They are eukaryotic cells
8. After four cycles of thermocycling, how many copies of the targeted region will be in the
PCR product?
A. 8
B. 16
C. 32
D. 64
9. What would be the effect on the PCRreaction if any of the following circumstances
arose: 1) there are no dNTPs in the reaction, 2) there is no Taq polymerase in the
reaction?
A. PCRwould proceed normally
B. Non-specific PCRof random templates will occur
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C. The reaction will cease after a few cycles
D. The PCRreaction will not commence
10. The following image represents the agarose gel results from the restriction digest of a 6
kb piece of DNA that possesses two restriction sites. Which of the following statements
is true?
D_ ...\\.
LDCUt
Dioest d
ladder
D:'.'-A
D_ -A
c::::I
6.0
-.o
-.0
-----
-c:::::::a c::::::::a
l. -
.0
A. The restriction digest was incomplete because the smallest DNA band is missing.
B. It is impossible to determine if the digest was successful.
C. The piece of DNA that was digested was not 6 kb long.
D. The 6 kb piece of DNA was completely digested by the restriction enzyme.
E. Two of the statements are true.
11. What is the major challenge in the production of RNA in eukaryotes compared to
prokaryotes?
A. Exporting the mRNA across the nuclear membrane
B. Importing the mRNA across the nuclear membrane
C. The mRNA staying inside the nuclear membrane
D. The mRNA translating into proteins within seconds
12. Which of the following method would you use to analyse gene expression changes?
A. Agarose gel electrophoresis
B. Southern blotting
C. Northern blotting
D. Calcium chloride transformation
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13. The DNA profiles below represent four different individuals.
A. B. C. D.
Which of the following statements is consistent with the results?
A. B is the child of A and C
B. C is the child of A and B
C. Dis the child of Band C
D. A is the child pf B and C
E. A is the child of C and D
14. Yeast artificial chromosomes contain which of the following elements?
A. Centromere only
B. Telomeres only
C. Origin of replication only
D. Centromeres and telomeres only
E. Centromere, telomeres and an origin of replication
15. Why does the restriction phenomenon in bacteria naturally occur?
A. For efficient cloning
B. Bacteria produce an enzyme
C. Destruction of bacterium's own DNA
D. For survival
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Section B: Answer all questions (85 Marks)
1. Developing nations like Namibia are now taking steps to build long-term plans to benefit
from biotechnology innovation and harness the potential of this field for economic
development and addressing societal problems.
Write to the President of Namibia, giving examples on how biotechnology can be used to
improve the livelihood of people in Namibia.
(20)
2. As part of your work with the Ministry of Health and Social Services, you are required to
produce COVID-19 vaccine in tobacco (Nicotiana bethamiana).
a. Outline with aid of diagrams, an experimental strategy that you will use to develop
COVID-19 vaccine in tobacco through genetic engineering.
(10)
b. What are advantages of producing recombinant in plants instead of bacterial cells. (4)
c. What is the difference between a selectable marker and reporter gene? Give
examples.
(3)
d. Detail the critical components of the growth medium that will be used to select for
bacteria cells that contains the recombinant plasmid containing the vaccine gene.
Explain how?
(2)
e. Tetracycline is an antibiotic. Some scientists are concerned about the gene for
resistance to kanamycin being present in maize which is released into the
environment. Suggest why?
(2)
f. Instead of using an antibiotic as a selectable marker, suggest any other safe
alternative method for screening transformants
(1)
3. Discuss some strategies that you can use to purify a recombinant protein produced in a
prokaryotic host.
(3)
4. Describe with the aid of diagrams how DNA can be used to identify a crime aspect.
Illustrate your answer by well labelled diagrams
(10)
5. Ms Lydia, a recent graduate in biotechnology gets so excited about genetic engineering
concepts she learnt in B1O702Sand wants to clone DNA extracted from potato leaves in
pBluescript llSK shown below plasmid.
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pBlutsni1lt Il SK+
(2961 b}l)
MCS
011
Firstly, she grinds up some potato tissues, extracts the DNA from it and digests the
DNA with two different restriction enzymes {separately, not together): fcoRI and
BamHI. She then obtains a cloning vector pBluescript 11SK and digests it with the
same two enzymes. She then runs a gel, which is shown below.
-em
""'CII
potato
1 i ,.!. LU QJI
vectic,r
i 1LU ca
[===::J c:::::::::J [===::J [===::J c:::::::::J
=
=- -
=
a. What are the key characteristics that plasmid pBluescript 11SK have that it can
be used for successful cloning
{4)
b. Why is it important for this plasmid to have an ampicillin-resistance gene? {3)
c. Which enzyme would she use for cloning the potato DNA: fcoRI, or BamHI?
Explain why you made your choice.
(3)
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d. Notice that the cloning vector made nice, tight bands on the gel, but the
potato DNA just looks like a smear with no distinct bands. However, this is just
what the Ms Lydia was expecting, so she's not worried about it at all. Explain
why this is the expected result.
(2)
e.
f. Ms Lydia now mixes the potato DNA (digested with the enzyme you specified
in part A) with cloning vector DNA (digested with the same enzyme). He then
adds the mixture to f. coli cells that have been treated with CaC!i, heats briefly
to 42°C, adds growth medium and incubate if for an hour. What would be his
next step? Be as specific as possible.
(2)
g. Unfortunately, after doing the next step as you specified, Ms Lydia doesn't
get a single bacterial colony. Not even one! When she reviews his procedure,
she realizes she left out a critical step. What did he forget, and why would
this be necessary?
(2)
6. Write short notes on
i. Namibia's Biosafety Act
(3)
ii. Precautionary principle?
(2)
iii. Terminator gene technology
(2)
iv. The Cartagena Protocol on Biosafety
(3)
7. Recombinant DNA technology tools and techniques have been copied from nature.
Discuss this statement giving at least four (4) relevant examples
(4)
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