Midterm 3 Review Questions

The process of DNA replication requires that each of the parental DNA strands be used as a __________ to produce a duplicate of the opposing strand.

• Catalyst
• Enzyme
• Template
• Copy

Identify which form of DNA repair this figure illustrates.

• Homologous Recombination
• Nonhomologous end joining
• mismatch repair
• excision repair

What role does DNA topoisomerase play?

• It binds the DNA polymerase to the template stand
• It fuses the Okazaki fragments together in the lagging strand
• It relieves tension built up at the replication fork
• None of the above

During DNA replication, the ____________ is synthesized discontinuously because it grows away from the replication fork, and the ___________ is synthesized continuously because it grows towards the replication fork.

• DNA, RNA
• RNA, DNA
• leading strand, lagging strand
• lagging strand, leading strand

What is the name of the enzyme labeled D?

• topoisomerase
• helicase
• DNA polymerase
• ligase

DNA polymerase can only add new nucleotides in one direction. Which direction is it?

• 3' to 5"
• 5' to 3'

Which of the following facts about telomeres is/are true?

• Telomeres are found at the ends of chromosomes.
• Telomeres protect the ends of chromosomes from degradation.
• Telomeres are made up of coding DNA sequences that contribute to protein production.
• Telomeres shorten with each round of cell division due to the removal of non-coding DNA.

In the image, you can see that the lagging strand ends up with gaps on the end after the RNA primers are removed. How does telomerase fix this end-replication problem?

• Telomerase uses its RNA template to allow repeating sequences to be added to the ends of the chromosome.
• Telomerase removes nucleotides on the end of the chromosome to remove overhangs.
• Telomeres use the other strand of DNA as a template to replicate the ends.
• None of the above

One common form of DNA damage is called ____________, it is the loss of an amino group from a cytosine in DNA to produce the base uracil

• Hydration synthesis
• Amino conversion
• Depurination
• Deamination

Which of the following steps in DNA repair comes last? 1. The nick or break in the helix is sealed by DNA ligase, the same enzyme that joins the Okazaki fragments during replication of the lagging DNA strand. 2.The damaged DNA is recognized and removed by one of a variety of mechanisms. 3. A repair DNA polymerase binds to the 3ʹ-hydroxyl end of the cut DNA strand. It then fills in the gap by making a complementary copy of the information stored in the undamaged strand.

• 1
• 2
• 3