UNIVERSITY OF LIMPOPO TURFLOOP CAMPUS FACULTY OF SCIENCE & AGRICULTURE SCHOOL OF MOLECULAR AND LIFE SCIENCES DEGREE AND DIPLOMA EXAMINATIONS (GENE EXPRESSION, FUNCTION & MOLECULAR BIOLOGY TECHNIQUES) INTERNAL EXAMINERS PROF L.J. MAMPURU DR V.G. MBAZIMA EXTERNAL EXAMINER PROF L-M BIRKHOLTZ THIS PAPER CONSISTS OF FIVE (5) PAGES INCLUDING COVER PAGE
1. Answer all questions. 2. Write neatly and legibly. 3. Answer sections A and B in separate answer books. 4. The Genetic code table is attached.
SECTION A QUESTION 1
Describe two functions of DNA supercoiling.
Discuss why a number of topoisomerase inhibitors are widely used as
If you see a DNA structure simply written as CATAGCCG, what exactly
does this mean in terms of a double-stranded structure and the polarity
of the two chains? Explain your answer fully.
Discuss the mechanism by which DNA polymerase III of E. coli
achieves a high standard of fidelity in DNA synthesis.
Explain the roles of the 5´-Cap and 3´-poly (A) tail of eukaryotic
Describe what up-promoter- and down-promoter-mutations are. (4)
There are about seven (7) proteins/enzymes that are utilized during the
process of Mismatch Repair. Identify these proteins/enzymes and
explain the role of each in the mismatch repair system.
The enzyme liverase is found only in the liver of mice (i.e., the enzyme
is not found in any other organ such as spleen). However, you find that
the gene encoding this enzyme is transcribed at equal rates in liver
and spleen cells. By defining the level of liverase gene expression as
the level of enzyme in the cell, list three points at which expression of
the liverase gene might be differentially regulated in liver and spleen
Describe the action of TWO of the following antibiotics. Also indicate
whether it is the prokaryotic and/or eukaryotic system that is/are
The following structure is a Non-Template DNA fragment of gene X: 5´-…TCTGACTATTGAGCTCTCTGGCACATAGCA…-3´
Write the mRNA sequence that could be transcribed from
Write the three possible reading frames that could be
obtained from the resultant mRNA in (i) above,
Indicate the amino acid sequences that correspond to each
of the reading frame above (ii). Clearly show the N- and C-
Calculate the total energy required to synthesize a polypeptide of 600
SECTION B QUESTION 1
Restriction endonucleases and restriction fragments
b) Describe any two important features of a cloning vector.
c) What is the role of dideoxy ribonucleoside triphosphates (ddNTPs) in DNA
d) Why is DNA polymerase from E. coli and other mesophilic bacteria not
a) Suppose that you have Drosophila gene R and you wish to find out if
Sheep also contain a similar gene. Describe how you would go about
detecting the presence of Drosophila gene R in Sheep.
You have attempted to ligate a 2 kb fragment of foreign DNA into the Pst1 site in
the multiple cloning site of the 3.4 kb plasmid vector shown below:
a) To confirm the presence of the fragment of foreign DNA you perform Pst1
restriction enzyme digest. Draw the agarose gel band pattern that you
would expect from the electrophoresis of recombinant and non-
recombinant plasmids digested with Pst1 (Show the positive and negative
electrodes, the direction of band movement and the sizes of the
b) Since the 2kb fragment of foreign DNA is inserted into a tetracycline
resistance gene in a plasmid, will cells containing the resulting
recombinant plasmid be sensitive or resistant to tetracycline? Explain.
TRIGEMINAL NEURALGIA ASSOCIATION NORTHEAST FLORIDA SUPPORT GROUP SUPPORT GROUP MEETING SATURDAY, MARCH 3, 2007 1:00-3:00 PM (Please note the new start time of 1:00 PM) Our first meeting of the year on February 27, 2007 was well attended, with 21 people attending. We welcomed a new member, Elaine Savitsky who was referred to our Support Group by Dr. Margaret Dennis. E
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