Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

QUIZ 3 > DNA Replication > Flashcards

DNA Replication Flashcards

1
Q

four basic rules of DNA replication

A

semi conservative, 5’ to 3’ direction, semi-discontinuous, defined origin and proceeds bidirectionally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

DNA synthesis proceeds in _ direction

A

5’ to 3’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

DNA can only add free nucleotides to _

A

3’ -OH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

leading strand

A

continuous synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

lagging strand

A

discontinuous synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

all DNA polymerases require _

A

a primer (usually RNA) that provides a free 3’ OH group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

properties of DNA polymerases

A

template-directed, dNTPs, free 3’-OH group, 5’ to 3’ direction, possess 3’ to 5’ exonuclease activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

e. coli origin of replication

A

only one site in bacteria –> OriC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

oriC

A

AT-rich region with protein-bound region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

helicase

A

breaks hydrogen bonds between two strands of DNA to unwind at OriC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

primase

A

lays down RNA primer and recruits DNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

SSB

A

single stranded binding protein –> binds to prevent reannealing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

gyrase

A

relieves tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

ATP

A

provides energy for helicase and gyrase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

polymerase mechanism

A

positions dNTP so there can be nucleophilic attack by 3’ OH –> pyrophosphate is released

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

DNA pol III

A

synthesizes both leading and lagging strands; has 3’ to 5’ exonuclease activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

ligase

A

seals nick between Okazaki fragments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

DNA polymerase I

A

removes primers from fragments (on 3’) and replaces gap with correct nucleotide –> 5’ to 3’ exonuclease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

DNA polymerase I has both _

A

5’ to 3’ and 3’ to 5’ exonuclease activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does DNA III polymerase ensure proccessivity?

A

has 2 beta subunit encircle the DNA to prevent it from disassociating (pol I will randomly fall off)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

DNA polymerase II

A

DNA repair in 3’ to 5’ direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

quinolones

A

ciproflaxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

quinolone action

A

disrupts type II topoisomerase, inhibiting gyrase from preventing super coiling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

anthrax treatment

A

quinolones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

RNA dependent DNA polymerase

A

reverse transcriptase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

retroviral infection

A

RNA genome that reverse transcribes to DNA –> integrates into host genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

reverse transcriptase does not have _

A

proofreading capability, so if an analog is incorporated, synthesis can be blocked by this “chain terminator”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

drugs for treating AIDS

A

AZT (zidovudine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

AZT (zidovudine)

A

analog of thymine –> HIV reverse transcriptase will bind –> AZT has no 3’ -OH so nothing can be added –> chain terminator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Why does AZT get taken up by reverse transcriptase?

A

it is converted to triphosphate form once in the cells, causing reverse transcriptase to bind with higher affinity than to dTTP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

differences in eukaryotic and prokaryotic DNA

A

eukaryotic genomes are bigger, replication occurs during a small portion of the cell cycle, DNA is bound by histones, chromosomes are linear

32
Q

DNA polymerase alpha

A

replication initiation; only one with primase

33
Q

DNA polymerase delta

A

synthesize lagging strand

34
Q

DNA polymerase beta

A

DNA repair

35
Q

DNA polymerase gamma

A

mitochondrial replication

36
Q

DNA polymerase epsilon

A

leading strand replication

37
Q

G1 phase

A

RNA and protein synthesis only

38
Q

S phase

A

DNA synthesis doubles amount of DNA in the cell

39
Q

G2 phase

A

no DNA synthesis

40
Q

M phase

A

mitosis

41
Q

G0 phase

A

withdrawal from cell cycle

42
Q

ARS

A

autonomous replication sequence containing a conserved 11bp sequence for binding sites of several proteins

43
Q

What happens if ARS is removed/inserted into another DNA?

A

confers DNA replication in a cellular extract

44
Q

proteins that bind ARS

A

ORC and ABF

45
Q

ORC

A

origin recognition complex

46
Q

ABF

A

ARS binding factor

47
Q

What happens during G1 stage?

A

ABF and ORC bind, recruiting other proteins needed –> DNA replication is not activated until these proteins are phosphorylated (by cdk’s)

48
Q

What happens after phosphorylation of ARS proteins?

A

helicase binds to separate strands and begin replication, phosphorylated proteins leave

49
Q

as soon as ARS is replicated _

A

ABF and ORC rebind

50
Q

polymerase alpha is replaced with _

A

pol epsilon on leading strand and pol delta on lagging strand

51
Q

both pol epsilon and pol delta have _

A

3’ to 5’ nuclease activity

52
Q

RNase H

A

digests the RNA primers

53
Q

How are RNaseH gaps filled?

A

DNA polymerase delta

54
Q

RPA

A

helix-destabilizing proteins (same as single stranded binding protein) –> prevents re-annealing to allow polymerases to bind

55
Q

polymerase complex

A

polymerase epsilon, PCNA (clamp), and RFC (clamp loader)

56
Q

PCNA & RFC have same role as _

A

beta subunits on DNA pol III in prokaryotes

57
Q

difference in lagging strand synthesis between prokaryotes and eukaryotes

A

in prokaryotes, DNA pol III does both leading and lagging; in eukaryotes, there are two separate polymerases

58
Q

lagging strand polymerase complex

A

pol delta, RFC, and PCNA

59
Q

telomeres

A

regions of repetitive noncoding DNA plus proteins located at end of linear chromosomes –> prevent DNA from being deleted since chromosomes are shortened each round of replication

60
Q

telomere repeat sequence

A

TTAGGG

61
Q

telomerase

A

extends telomeres

62
Q

telomerase 2 components

A

RNA-directed DNA polymerase, RNA template

63
Q

Which cells have telomerase?

A

germ cells and stem cells and blood cells; usually not somatic

64
Q

somatic cells have a _

A

limited replication potential, so do not need telomerase –> once telomere is gone, cell stops dividing

65
Q

cancer cells

A

express telomerase to provide unlimited dividing potential

66
Q

telomeres too long

A

will live too long, allowing for mutation

67
Q

telomeres too short

A

increases senescence

68
Q

mtDNA replication

A

pre-formed RNA transcripts hybridize to lagging strand as DNA leading strand proceeds –> after leading strand is replicated, polymerase will come back, remove RNA, and start synthesizing lagging strand DNA

69
Q

mechanism of quinolone antibiotics

A

inhibit topoisomerase II (gyrase) –> prevents topoisomerase from removing supercoils, stopping DNA replication

70
Q

influenza

A

replicates with an RNA-dependent RNA-polymerase; RNA virus

71
Q

ribavirin

A

nucleoside analog; anti-viral drug which is active against a number of DNA and RNA viruses –> stops viral RNA synthesis

72
Q

nucleoside analogs

A

arabinosylcytosine, fludarbine, remdesivir

73
Q

fludarabine

A

purine analog that inhibits DNA polymerase; used for chemotherapy

74
Q

arabinosylcytosine

A

cytidine analog, chemotherapy drug

75
Q

remdesivir

A

adenosine analog; interferes with viral RNA-dependent RNA polymerase; used for COVID-19, and ebola

QUIZ 3 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions