DNA Structure and Replication Flashcards
(7 cards)
1
Q
Double-ring structure
Adenine, Guanine
A
Purines
2
Q
Single-ring structure
Cytosine, Thymine
A
Pyrimidines
3
Q
Adenine (A) + Thymine (T)
A
2 hydrogen bonds
4
Q
Cytosine (C) + Guanine (G)
A
3 hydrogen bonds
5
Q
Helicase unwinds DNA, creating a replication fork
Topoisomerase prevents supercoiling
Single-strand binding proteins (SSBs) stabilise the unwound strands.
A
Initiation
6
Q
Primase adds an RNA primer
DNA polymerase III synthesizes the new strand 5’ to 3’
Leading strand: Synthesized continuously
Lagging strand: Synthesized in Okazaki fragments, joined by DNA ligase
A
Elongation
7
Q
DNA polymerase I removes RNA primers and replaces them with DNA.
Ligase seals gaps between fragments.
A
Termination
