Question

1. The clamp loader loads the sliding clamp onto the DNA. Review the steps listed below. Which step would come SECOND?

a) ATP binds to the y (gamma) subunits, which undergo a conformation change.

b) Double-stranded DNA passes through the ß clamp.

c) They (gamma) — p clamp —ATP complex binds primed DNA.

d) Y (gamma) subunits bind to and open the clamp.

e) Single-stranded DNA passes through the side of the ß clamp loader gap.

2. Which of the following describes the approximate chromosomal location of the termination of replication in bacteria?

a) Termination occurs at oriC once the replication fork has advanced the entire length of the chromosome.

b) Termination occurs at a location one-quarter around the chromosome.

c) Termination occurs at a location halfway around the chromosome.

d) Termination occurs at random locations where replication forks collide.

e) Termination occurs at the first Ter site encountered by the replication fork.

3. Eukaryotic DNA replication initiates replication at multiple origins of replication simultaneously. How is eukaryotic replication initiated to ensure simultaneous initiation at multiple origins?

a) A Pre-replication complex (preRC) is formed at all hemimethylated origins.

b) The Pre-replication complex (preRC) forms in Go phase.

c) Cyclin-dependent protein kinase (CDK) enzymes are active during formation of PreReplication Complex (preRC).

d) Cyclin-dependent protein kinase (CDK) enzymes activate the Pre-RC to allow for coordinated activation of replication once other replication factors associate to form the Replication Complex (RC).

e) None of these answers is correct.

4. Eukaryotes solve the problem of replicating the ends of their linear chromosomes by:

a) terminal redundancy whereby each end of the chromosome is duplicated allowing recombination.

b) using a protein as a primer.

c) by covalently linking the two strands at each end of the linear chromosome to form a circle.

d) enzyme activity that uses an RNA template and reverse transcription in a series of repeating cycles.

e) all of the above.

5. Why is primase required for replication?

a) DNA polymerases cannot begin DNA synthesis without a primer containing a free 3 OH.

b) DNA polymerases can only begin DNA synthesis if they are stimulated by dimerization with a primase subunit.

c) Primase is required to recruit helicase to the site of DNA synthesis.

d) Primase is required for proofreading DNA during replication.

e) Primase is required for removal of RNA primers during replication.

Answer 1

1. (e) Single-stranded DNA passes through the side of the ß clamp loader gap.

2. (e) Termination occurs at the first Ter site encountered by the replication fork.

3. (c) Cyclin-dependent protein kinase (CDK) enzymes are active during formation of PreReplication Complex (preRC)

4 (e) e) all of the above.

5 (a) DNA polymerases cannot begin DNA synthesis without a primer containing a free 3 OH.