[1] LEC: DNA Replication

Question 1

DNA replication occurs in which phase of the cell cycle?

Answer 1

S phase

Question 2

The single strand binding protein is important in which stage of DNA replication?

Answer 2

initiation

Question 3

This enzyme is important because it destroys and creates bonds ahead of the replication fork to relieve the torsion and stress caused by the replication bubble

Answer 3

topoisomerase

Question 4

The extension of a strand of DNA after the addition of a primer is facilitated by ___

Answer 4

DNA polymerase III

Question 5

Telomerase is important in which step of DNA replication?

Answer 5

Termination

Question 6

If DNA polymerase I were mutated so that all its enzymatic activities were inactive, which part of replication would be most affected?

a. synthesis of okazaki fragments
b. joining of okazaki fragments

Answer 6

b

Question 7

Okazaki fragments are used to elongate the ___ strand ___ (away or towards) the replication fork

Answer 7

lagging
away

Question 8

T/F: During semiconservative replication, the original double helix template remains intact and a new double helix forms

Answer 8

F

Question 9

T/F: the single stranded binding protein destroys the bonds between adenine and thymine to form the replication bubble

Answer 9

F

Question 10

Since the first nucleotides cannot be linked in a newly synthesized strand in DNA replication, ___ is required

Answer 10

RNA primer

Question 11

What would happen when the two replication forks meet each other and fuse?

Answer 11

Termination

Question 12

Telomerases are responsible for the progressive synthesis of telomeric DNA repeats of ___

Answer 12

TTAGGG

Question 13

___ join DNA fragments to the lagging strand

Answer 13

ligases

Question 14

In the replication of DNA, the helix is opened and untwisted by ___

Answer 14

helicase

Question 15

How many replication fork/s is/are there in a replication bubble?

Answer 15

2

Question 16

Sites at which single-stranded DNA is exposed, and at which DNA synthesis occurs

Answer 16

replication fork

Question 17

Direction of DNA replication

Answer 17

5’ to 3’

Question 18

Specialized sites where DNA replication starts

Answer 18

Origin of replication

Question 19

T/F: the origin of replication is where the DNA double helix is opened

Answer 19

T

Question 20

In the initiation phase, the ___ breaks the bonds between the double helix structure

Answer 20

Pre-replication protein complex

Question 21

This protein prevents the reannealing of the single stranded structure and prevents the DNA from being degraded by nucleases

Answer 21

Single stranded binding proteins

Question 22

The enzyme that harnesses the chemical energy from the ATP hydrolysis to separate two DNA strands

Answer 22

helicase

Question 23

The action of this enzyme usually causes tension and torsion

Answer 23

helicase

Question 24

Fights positive supercoils by putting negative supercoils ahead of the replication fork, thus, the torsional strain is released

Answer 24

topoisomerase (II - gyrase)

Question 25

Topoisomerase I are present in what type of organism/s?

Answer 25

eukaryotes

Question 26

Topoisomerase II are present in what type of organism/s?

Answer 26

eukaryotes/prokaryotes

Question 27

Topoisomerase IV are present in what type of organism/s?

Answer 27

prokaryotes

Question 28

Examples of anticancer drugs made from topoisomerase I

Answer 28

Irinotecan, topotecan

Question 29

Examples of anticancer drugs made from topoisomerase II

Answer 29

Etoposide, tenoposide, fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin, ofloxcain, gemifloxacin, delafloxacin)

Question 30

The elongation during replication is in what direction?

Answer 30

5' to 3'

Question 31

They are responsible for copying a short stretch of DNA template strand to produce RNA primer

Answer 31

primase

Question 32

Hydrogen-bonded to template and provides a stable framework to which the nascent chain starts to grow

Answer 32

primase

Question 33

The cut-and-patch process is also called the ___

Answer 33

nick translation

Question 34

Seals the nick between the new strands in the lagging strans

Answer 34

ligase

Question 35

Occurs when the two replication forks moving away from the single origin of replication meet on the opposite side of the circle

Answer 35

termination

Question 36

when the forks approach each other, the replication complex disseminates and ___ occur

Answer 36

termination