DNA Replication Assignment
Your notes and textbook inform you of the functions of all of the enzymes and proteins involved in DNA replication. The questions below deal with situations in which one or more of these proteins has been altered. By knowing what the protein does in the normal situation, you should be able to reason through what happens when the particular protein is altered.
Your answer cannot be as simple as “The DNA would not be replicated.” You have to describe the normal process and then explain how this specific process is altered. You also need to then go on to state whether the process might be slower, or faster or result in a less stable DNA molecule or etc. and indicate which other enzymes of proteins will be affected.
eg. Compared to a normal situation, EXPLAIN what would happen if a mutation occurred that caused
DNA gyrase to stop functioning.
Normally: DNA gyrase releases the tension of the unwound DNA
Mutation: without this release of tension, the replication fork will close and DNA polymerase I,
DNA primase, DNA polymerase III and DNA ligase may not be able to function
All questions are worth 3 marks à 1 mark for the normal situation and 2 mark for the consequences [except question # 2 at 2 marks].
1. Compared to a normal situation, EXPLAIN what would happen if a mutation occurred that allowed
DNA polymerase III to travel equally well 3’ à 5’ and 5’ à 3’.
2. Compared to a normal situation, EXPLAIN what would happen if a mutation occurred that allowed
short segments of DNA to be as sticky as short segments of RNA.
3. Compared to a normal situation, EXPLAIN what would happen if a mutation occurred that resulted
in DNA polymerase I being incapable of bonding to uracil.
4. Compared to a normal situation, EXPLAIN what would happen if a mutation occurred that
prevented DNA ligase from functioning, but did not affect any other enzymes or proteins.
5. Compared to a normal situation, EXPLAIN what would happen if a mutation occurred that
prevented any protein other than enzymes from bonding with DNA.
6. Compared to a normal situation, EXPLAIN what would happen if a mutation occurred that resulted
in DNA polymerase enzymes functioning in numeric order.
7. Compared to a normal situation, EXPLAIN what would happen if a mutation occurred that resulted
in DNA primase being incapable of bonding to uracil.
8. Compared to a normal situation, EXPLAIN what would happen if a mutation occurred that
prevented the enzymes that work with double stranded DNA from functioning.