05a: DNA Replication Flashcards Preview

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Flashcards in 05a: DNA Replication Deck (45):
1

T/F: DNA replication is the most accurate biological process.

True

2

DNA replication uses (non-activated/activated) substrates, (X).

Activated;

X = dNTPs

3

4 steps for DNA replication. In what order do they occur?

1. Initiation
2. Priming
3. Synthesis
4. Termination

All occur simultaneously

4

Bacterial DNA has (X) shape and how many start sites for replication?

X = circular

One start site (oriC)

5

OriC is recognized by:

DnaA (initiator protein)

6

Prok:
Initiator protein, (X), combines with (Y) and interacts with DNA in what way?

X = DnaA

Y = Histone-like proteins (and ATP)

Tight association with DNA, so bends it

7

Why does replication bubble form?

DnaA bends DNA and AT-rich repeats near OriC open to form bubble

8

Prok:
DnaB is called (X) and forms complex with (Y), which helps it bind the DNA.

X = helicase

Y = DnaC

9

Prok:
When does DnaA displace from DNA?

Once helicase binds

10

Prok:
(X) bind(s) DNA, preventing its coiling, once primase, aka (Y), binds.

X = SSBs

Y = DnaG

11

T/F: in bacteria, binding of each DNA replication protein to DNA requires ATP.

True

12

Which DNA polymerase initiates strand synthesis in bacteria?

None! No DNA pol can initiate new strand synthesis

13

RNA primer is created in which direction? About how long is it?

5' to 3' direction;

5-10 NT

14

There are (X) number of prokaryotic DNA polymerases. Which ones are critically mainly for panicked cell?

X = 5

DNA polymerase 2, 4, 5

15

DNA polymerase I is known for:

Primer excision (and some repair) in prokaryotes

16

DNA polymerase 3 is known for:

Replication chain elongation (and some repair) in prokaryotes

17

List activities of DNA pol 1.

(Prokaryotes)

1. Polymerase
2. 3' exonuclease (repair)
3. 5' exonuclease (primer excision)

18

What does a polymerase's processivity signify?

Number of NT it can add before dissociating from DNA

19

Which prokaryotic DNA polymerase has the greatest processivity?

DNA pol 3

20

Replication bubble has how many DNA polymerase 3?

2 (one at each end of fork)

21

Which subunit on DNA pol 3 is responsible for proof reading? What's its specific function?

Epsilon (3' exonuclease)

22

Which subunit on DNA pol 3 is responsible for primer excision? What's its specific function?

DNA pol 3 doesn't remove primer - DNA pol 1 does that (5' exonuclease)

23

How many different subunits does DNA pol 3 have?

10

24

Which subunit on DNA pol 3 is responsible for replicating strands?

Polymerase (alpha subunits)

25

T/F: in DNA pol 3, the clamp loader is separate from the core enzyme.

True

26

Which subunit on DNA pol 3 is the sliding clamp?

Beta subunit

27

Which subunit on DNA pol 3 is the clamp loader?

Gamma complex

28

DNA pol 3 replicates (leading/lagging) strand first.

Neither - replicates both strands simultaneously

29

The sliding clamp for DNA pol 3 has inner diameter of (X) and mainly (negative/positive/neutral) AA on inside.

X = 3.5 nm

Negative

30

How can DNA pol 3 detect mismatched bases and correct itself?

Defects change in DNA structure

31

In bacteria, where is the termination site, wrt OriC?

180 degrees from it

32

Nick translation, carried out by (X), removes how many (Y) at a time?

X = DNA pol 1
Y = RNA primer
1 at a time

33

T/F: Nick translation requires ATP.

False - DNA pol 1 uses water (hydrolysis) for 5' exonuclease

34

The nick after primer removal is sealed by:

DNA ligase

35

What's the final step in bacterial termination of DNA synthesis?

Type 2 topoisomerase separates the two interlinking strands of replicated circles and refolds DNA into supercoils

36

DNA pol gamma is responsible for:

Eukaryotic DNA replication in mitochondrion

37

Eukaryotic equivalent to beta subunit on prokaryotic DNA pol (X).

X = 3

Beta subunit is clamp; PCNA in euk

38

DNA pol epsilon is responsible for:

Eukaryotic DNA synthesis of leading strand

39

DNA pol delta is responsible for:

Eukaryotic DNA synthesis of lagging strand

40

Primer removal in eukaryotes is carried out by:

Rnase H and Fen1

41

Helicase in eukaryotes is called:

MCM

42

Origin of replication in euk is called:

ARC (autonomous replicating sequences)

43

T/F: Topoisomerase II requires ATP for its function.

True

44

What makes DNA Pol (X) better suited for primer excision than DNA Pol (Y)?

X = 1
Y = 3

Low processivity

45

T/F: Type II Topoisomerase only adds negative supercoils.

False