Lecture 11

Question 1

replication origin is in enriched in what?

Answer 1

A + T

Question 2

what are the steps of the initiation of DNA replication?

Answer 2

1 - Origin Recognition Complex (ORC) associates with the replication origin
2 - using CDC6 and CTD1 binding of ORC recruits the replicative helicase Minichromosome Maintenance Proteins (MCM)
3 - MCM forms replication bubble
4 - DNA-binding protein called Replication Protein A (RPA) holds open replication bubble
5 - DNA polymerase and primase are loaded

Question 3

what does the Pol alpha primase do?

Answer 3

initiation of replication and initiation of okazaki fragments

Question 4

what does Pol delta do?

Answer 4

elongation and maturation of okazaki fragments

Question 5

what does Pol epsilon do?

Answer 5

replisome assembly and leading strand synthesis

Question 6

what is the role of topoisomerases?

Answer 6

• they bind and cut ss or ds DNA strands ahead of the replication fork to prevent supercoiling which would eventually halt replication. The cuts are later resealed.

Question 7

what is idopathic pulmonary fibrosis?

Answer 7

• lung scarring that results in abnormal gas exchange characterized by shortness of breath and is undetectable.

Question 8

what is aplastic anemia?

Answer 8

• insufficient amount of red blood cells, wbc, or platelets

- stems cells cannot proliferate