SBI4U
UNIT 4 TEST REVIEW: MOLECULAR GENETICS
BIG IDEAS
 DNA contains all the genetic information for any living organism.
 Proteins control a wide variety of cellular processes.
 Genetic research and biotechnology have social, legal, and ethical implications.
1. Compare and contrast DNA and RNA.
2. Make a list of enzymes involved in DNA replication and list their functions. Compare and contrast
DNA replication and PCR.
3. DNA polymerase III can only extend an existing DNA strand in the 5' → 3' direction. Describe the
mechanism that compensates for its inability to initiate a strand.
4. One strand of a DNA molecule contains the nucleotide proportions
15% adenine
30% thymine
20% guanine
35% cytosine
What proportions of the four base pairs would you expect in the double-stranded form of this DNA?
5. Provide two reasons that explain why coupled transcription-translation is not possible in eukaryotes.
6. You have been put in charge of creating a bacterial plasmid for the production of insulin. How
would you achieve this? How would the sequence for insulin used in the plasmid be different from the
sequence in a eukaryote?
7. Briefly describe the five levels of control in eukaryotic cells:
a) epigentic
b) transcriptional
c) post-transcriptional
d) translational
e) post-translational
8. Describe the consequences to eukaryotic protein synthesis if the following were inactivated
a) spliceosomes
b) RNA polymerase
c) poly-A polymerase
d) tRNA
e) ribosomes
9. The following polypeptide sequence has been obtained from a protein found in eukaryotic cells:
leu-gly-pro-val-arg
a) Make a possible mRNA that may have coded for this protein.
b) Explain why more than one sequence may exist.
c) Make the possible pre-mRNA for this protein, clearly indicating what makes it different from (a)
d) Make a possible DNA coding strand for this protein, clearly indicating regulatory sequences that are
present in DNA but absent in mRNA
SBI4U
10. Ribosomes are proteins. What would be the potential consequence of allosterically
inhibiting the E site of a ribosome? Explain.
11. Use the gel electrophoresis results to answer the
following questions
a) how was the DNA used in this gel obtained?
b) how was the digestion performed?
c) how was the pattern obtained?
d) explain how you would know who committed the
crime?
12. Is gene therapy a viable method for treating
most diseases? Explain your answer.
13. An aquaculture research corporation based in
Prince Edward Island has created a variety of GMO
salmon that grows 10 times faster than wild salmon.
a) what are the advantages of this GMO?
b) what are the potential risks?
c) what regulations would you recommend for the use
of this fish in fish-farming operations?
14. Design a primer 10 nucleotides in length that would anneal to the following DNA sequence in a PCR
reaction:
5’- GATGGCGTACCACTGTCGAATGCCCGTAATGTTCCGA-3’
15. Use the gel electophoresis pattern from a dideoxy sequencing to determine the sequence of the
original template DNA.