Brainscape's Knowledge GenomeTM

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


See full index

ML2001: Introductory Molecular Biology > DNA Metabolism - Replication > Flashcards

DNA Metabolism - Replication Flashcards

1
Q

What is the function of Polymerases?

A

Synthesis DNA

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

What is the function of Nucleases?

A

Digest DNA
(endo and exonucleases)

Endo - cleave in middle; Exo - cleave at end

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

What is the function of Ligases?

A

Ligate (join) DNA fragments

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

When does DNA replication occur?

A

During cell division

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

When does DNA synthesis occur?

A

During S phase of cell cycle

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

What are the SIX fundamental rules for DNA replication?

A
  1. Semi-conservative
  2. Starts at origins
  3. Always synthesised 5’ to 3’
  4. Semi-discontinuous
  5. Synthesised by DNA Polymerases
  6. Very accurate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How many origins of replication do Eukaryotic cells have?

A

Multiple

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

How many replication forks does E. coli have?

A

2

(Bidirectional)

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

What end are nucleotides added to during DNA synthesis?

A

3’ end of new strand

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

What direction are template strands read in?

A

3’ to 5’ end

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

Which strand of DNA is synthesised continuously?

A

Leading strand

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

Which strand of DNA is synthesised in fragments?

A

Lagging strand

(Ozaki fragments)

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

Which DNA Polymerase is involved in adding nucleotides to the 3’ end of DNA?

A

DNA Pol I

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

What is required for DNA Polymerase to synthesise DNA?

A
  • Template strand
  • Free 3’ OH
  • Primer (RNA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why do mistakes in DNA synthesis only occur 1 in 10^9 to 10^10 bases?

A

Base Pairing:
Only correct base pairs fit in enzyme active sites

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

What improves the accuracy of DNA synthesis?

A

Intrinsic 3’ to 5’ exonuclease activity in DNA Polymerase
(Proofreading)

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

What is the specialised function of DNA Pol I?

A

5’ to 3’ exonuclease activity

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

What is the function of Klenow?

A

Proof reading & Polymerisation

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

What part of Pol I does the Insertion and Postinsertion sites sit?

A

Palm

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

How does the polymerase proofread in DNA replication?

A
  • Forward movement is impeded
  • Polymerase repositions to remove and replace mis-paired nucleotide
20
Q

How does the polymerase proofread in DNA replication?

A
  • Forward movement is impeded
  • Polymerase repositions to remove and replace mis-paired nucleotide
21
Q

How many enzymes and proteins are involved in DNA replication in E. coli?

A

20 plus DNA Pol III

22
Q

What is the DNA synthesis complex known as in E. coli?

23
Q

What is the function of Helicases?

A

Separate parent DNA strands (ATP)

24
Q

What is the function of Topoisomerases?

A

Control separation stress and twisting

25
Q

What is the function of Single Strand DNA Binding Proteins?

A

Stabilise strands

26
Q

What is the function of Primases?

A

Lay down RNA primer

27
Q

What is the function of DNA Pol I?

A

Replaces RNA primer with DNA

28
Q

What is the function of DNA Ligases?

A

Close nicks

29
Q

What are the THREE stages of DNA Replication?

A
  1. Initiation
  2. Elongation
  3. Termination
30
Q

What is the Initiation phase of DNA replication?

A

Regulated process so that DNA replication occurs only one in every cell division

31
Q

Where does initiation occur in E. coli?

A

At Ori C - origin of replication site

32
Q

How many base pairs does the replication of origin, Ori C, contain in E. coli?

33
Q

What is the DNA Unwinding Element (DUE) on the E. coli replication of origin site?

A

Three 13bp A-T rich repeats

34
Q

Where does the key initiator protein DnaA bind to on the E. coli origin of replication site?

A

Five 9bp repeats
(R1 - R5)

35
Q

What are the steps for the Initiation Phase of DNA replication in E. coli?

A
  1. DnaA (ATPase) binds to R1-R5 sites
  2. Denatures DNA at A-T rich DNA Unwinding Element (DUE)
  3. DnaB (helicase) binds unwound DNA
  4. Unwinds DNA in both directions
  5. SSB proteins and Topoisomerase II stabilise DNA strands
  6. Thousands of bases become unwound
36
Q

What are the steps for LEADING strand synthesis in the Elongation phase of DNA replication?

A
  1. Primase synthesises 10-60 nucleotide RNA primer at origin
  2. Nucleotides added successively by DNA Pol III
  3. Synthesis proceeds continuously
  4. Keeps pace with replication fork
37
Q

What is the name of the protein complex on the lagging strand in the Elongation phase of DNA replication?

38
Q

What are the steps for LAGGING strand synthesis in the Elongation phase of DNA replication?

A
  1. Primer synthesised at intervals
  2. Each primer extended by Pol III
  3. Synthesis extends as far as previous primer
  4. RNA primers removed
  5. Replaced with DNA by Pol I
  6. Nicks closed with DNA ligase
39
Q

Why does DNA Pol III holoenzyme has three sets of core subunits?

A

So one or two Okazaki fragments can be synthesised simultaneously, along with the leading strand

40
Q

Where do the replication forks meet in the Termination phase of DNA replication in E. coli?

A

At the terminus region:
Ter sequences

41
Q

What complex arrests replication in the Termination phase of DNA replication in E. coli?

A

Ter-Tus complex

42
Q

What enzyme is involved in the separation of circles in the Termination phase of DNA replication in E. coli?

A

Topoisomerase IV

43
Q

How many times does DNA replicate per cell division cycle in Eukaryotes?

44
Q

What controls the replication of DNA in Eukaryotes?

A

Cyclins & Cyclin-dependent kinases

45
Q

How many polymerases are involved in DNA replication in Eukaryotes?

A

Five or more

46
Q

What is the function of DNA Pol a?

A

Primer synthesis

47
Q

What is the function of DNA Pol d?

A

Leading and lagging strand synthesis (PCNA)

Acts like Pol III

48
Q

What is the function of DNA Pol e?

A

DNA repair

ML2001: Introductory Molecular Biology (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions