Cell bio Flashcards Preview

STEP 1 > Cell bio > Flashcards

Flashcards in Cell bio Deck (12):
1

What is the function of topoisomerases?

reduce DNA supercoiling by introducing breaks, **negative coiling** and ligation of the breaks

2

What are two major features of heterocromatin? What is the key consequence of these features?

heavily methylated DNA
deacetylated histones

low transcriptional activity

3

What is more likely to introduce faulty repair, double or single stranded DNA breaks?

double

4

hereditary non-polyposis colorectal cancer is associated with impaired _____

mismatch repair

5

what enzyme is responsible for unwinding the double helix?

helicase

6

what removes supercoils in prokaryotic DNA replicaiton?

topoisomerase II (DNA gyrase)

7

what facilitates the stabilization of unwound template strands of DNA during prokaryotic DNA replication?

dingle stranded DNA-binding proteins

8

what enzyme synthesis the RNA during prokaryotic DNA replication?

primase (aka RNA polymerase)

9

what facilitatees 5' to 3' DNA synthesis and also has 3' to 5' exonuclease "proofreading" activity during prokaryotic DNA replication?

DNA polimerase I and III

10

What removes teh RNA primer (5' to 3' exonuclease acvity) and replaces it with DNA during prokaryotic DNA replication??

DNA polimerase I

11

what joinds the okazaki graments (lagging strand) during prokaryotic DNA replication?

DNAse liga

12

what is required for DNA polimerase III to begin 5'=>3' synthesis of DNA?

RNA primer

Decks in STEP 1 Class (77):