Brainscape's Knowledge GenomeTM

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


See full index

BIOL200 > 8. DNA replication > Flashcards

8. DNA replication Flashcards

1
Q

replication fork

A

region at which replication is occurring

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

DNA helicase

A

unwinds DNA strands, beginning at origins

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

DNA polymerase requires…

A

dNTPs and a primer (usually RNA)

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

DNA topoisomerase

A

removes supercoils and reduces torsional stress caused by local unwinding

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

primase

A

specialised RNA polymerase that forms a short RNA molecule complementary to a single-stranded region of unwound duplex DNA

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

leading strand

A

continuous replication in 5’ to 3’ direction by DNA polymerase following the movement of replication fork

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

lagging strand

A

discontinuous replication in opposite direction from movement of replication fork

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

lagging strand replication process

A
  1. DNA elongated from RNA primer by DNA polymerase
  2. Okazaki fragments formed: short, discontinuous fragments consisting of DNA and RNA
  3. RNA part of Okazaki fragments replaced by DNA
  4. 2 adjoining DNA molecules ligated together by DNA ligase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

replisome

A

molecular machinery that carries out DNA replication

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

components of the replisome

A
  • CMG helicase
  • Replication Protein A (RPA)
  • DNA Pol Epsilon
  • PCNA
  • Pol Alpha - Primase complex
  • Pol Delta - PCNA complex
  • RFC - PCNA complex
  • Ribonuclease H and FEN-1
  • Pol Delta
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

CMG Helicase

A
  • binds to leading strand
  • unwinds parent strands at replication fork through ATP hydrolysis
  • contains accessory subunits Cdc45 and GINS complex: inactive without them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Replication Protein A (RPA)

A
  • binds single-stranded DNA to keep its template in optimal conformation for DNA polymerase (Pol Delta)
  • prevents formation of secondary structures on single-stranded DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

DNA Pol Epsilon

A

carries out leading strand DNA synthesis, forming a complex with PCNA

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

PCNA

A
  • prevents Pol Epsilon/Delta from dissociating from the template
  • homotrimeric protein (made of 3 monomers)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Pol Alpha - Primase complex

A
  • primase forms RNA component of primer
  • Pol Alpha extends primer with DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pol Delta - PCNA complex

A
  • on the lagging strand
  • replaces Pol Alpha - Primase complex and completes synthesis of Okazaki fragments
17
Q

RFC - PCNA complex

A

RFC (Replication Factor C) is PCNA loader: opens PCNA ring and loads it at primer on DNA

18
Q

Ribonuclease H and FEN-1

A

displace RNA components at 5’ ends of Okazaki fragments

19
Q

Pol Delta

A

replaces RNA with DNA

20
Q

Origin Replication Complex (ORC)

A

6 subunit protein that marks replication origins and load helices, tightly regulating DNA replication in eukaryote

21
Q

MCM helicase activation/deactivation

A
  • inactive form when loaded in G1 phase of cell cycle
  • activated in S phase of cell cycle through phosphorylation + interactions with other proteins
22
Q

DNA replication process

A
  1. unwinding of DNA by CMG helicase driven by ATP hydrolysis
  2. RPA binds to single-stranded regions
  3. Pol Alpha - Primase complex synthesises primer sequences through base pairing
  4. Pol Epsilon - RFC - PCNA complexes replace Pol Alpha complexes and extend primer sequences
  5. further unwinding and binding of RPA gives rise to 2 replication forks
  6. Pol Epsilon - RFC - PCNA complexes continue to synthesise leading strands
  7. Pol Alpha - Primasse complexes form primers for lagging strand synthesis
  8. primer extension + Pol Alpha-Primase complexe replacement done by Pol Epsilon - RFC - PCNA complexes
  9. primer removal by FEN-1 and ribonuclease H
  10. strands ligated together by DNA ligase
23
Q

DNA replication requires… (3)

A
  • a single stranded DNA sequence
  • a primer base paired to template with a free OH group
  • a source of dNTPs
24
Q

DNA polymerase

A

extends the primer to form a new nucleotide: Pol Alpha does initial elongation, followed by Pol Delta

25
Q

Okazaki fragments

A

discontinuous DNA segments on the lagging strand

26
Q

DNA ligase

A

joins adjacent Okazaki fragments

BIOL200 (6 decks)

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