DNA Replication Shit

Question 1

In prokaryotes, what cuts both strands of the DNA simultaneously?

Answer 1

Type II Topoisomerase

Question 2

What happens after the strands are cut in prokaryotes?

Answer 2

The ends of the DNA are separated and a second DNA duplex passes through the break.

Question 3

What happens after the second DNA Duplex is passed through the break in prokaryotes?

Answer 3

The cut DNA is re-ligated

Question 4

Which are faster: DNA Polymerases in prokaryotes or eukaryotes?

Answer 4

Prokaryotes (1000k bases/sec vs 50 bases/sec)

Question 5

DNA Polymerase requires a BLANK which is a short segment of nucleotides attached to the template strand. What is blank?

Answer 5

RNA Primer

Question 6

What does a primer contain that allows dNTPs to combine with?

Answer 6

A free 3’ OH group

Question 7

What synthesizes and places the RNA primer onto the DNA strand?

Answer 7

Primase

Question 8

What protein relieves twisting forces on the DNA helix?

Answer 8

Topoisomerase

Question 9

What protein opens the double helix?

Answer 9

Helicase

Question 10

What stabilizes single strands of DNA?

Answer 10

Single-strand DNA-binding proteins (SSBP)

Question 11

What DNA Polymerase is most common in bacteria?

Answer 11

DNA Polymerase III

Question 12

What DNA Polymerase is most common in humans?

Answer 12

DNA Polymerase d

Question 13

What direction is the lagging strand being synthesized? (Not asking about prime ends)

Answer 13

Away from replication fork discontinuously

Question 14

What are the discontinuous fragments of DNA called?

Answer 14

Okazaki Fragments

Question 15

What replaces the RNA Primer with them with nucleotides?

Answer 15

DNA Polymerase I

Question 16

What removes the primer on the leading strand?

Answer 16

DNA Polymerase I

Question 17

What fills in the gaps in the sugar phosphate backbone?

Answer 17

DNA Ligase

Question 18

What is the entire machine that is responsible for DNA replication called?

Answer 18

Replisome

Question 19

What does telomerase do?

Answer 19

It extends the unreplicated end of the lagging strand which allows more of it to be replicated (has its own RNA template) by DNA polymerase

Question 20

What protein proofreads DNA?

Answer 20

DNA Polymerase III

Question 21

What direction is DNA Polymerase III exonuclease activity?

Answer 21

3’-5’

Question 22

In E. Coli, how do they proofread DNA?

Answer 22

Methylated adenines allow the E. Coli to tell which strand was the original and to correct the one without a methylated adenine

Question 23

What does UV damage create?

Answer 23

Thymine dimers

Question 24

What is nucleotide excision?

Answer 24

Removing a large chunk of bases that have an error and replacing them with new bases

Question 25

What is the difference between a ddNTP and a dNTP and what are ddNTPs used for?

Answer 25

DdNTP lacks a hydroxyl group on the 3’ carbon, it is used to stop polymerization which allows for DNA sequencing

Question 26

What terminus does the 5’ end of the mRNA code for?

Answer 26

The N-terminus (basically its made first)

Question 27

What is a non-synonymous mutation?

Answer 27

One that changes the coded polypeptide chain

Question 28

What is a synonymous mutation?

Answer 28

A mutation that doesn’t change the encoded polypeptide chain