Ch 13 Flashcards
1
Q
template strand
A
strand that is copied
2
Q
primer strand
A
complementary DNA strand that is being synthesized
3
Q
DNA occurs in the
A
5–>3 direction
4
Q
Replication fork
A
point where both strands are being replicated
5
Q
leading strand
A
strand is synthesized in a conitnous fashion
6
Q
lagging strand
A
strand must be synthesized in a discontinuous fashion
7
Q
Replication origin
A
- Where DNA synthesis begins
- Begins when a protein binds to a unique DNA sequence found at all replication origins
- Two replication forks emerge from a replication origin and proceed in opposite direction away from each other
8
Q
RNAP vs DNAP
A
- RNA polymerases can start RNA synthesis from scratch
- DNA polymerase cannot start from scratch and always need a bit of RNA or DNA (primers) attached to the DNA strand in order to insert a dNTP
9
Q
helicase
A
unwinds the DNA strand
o shaped like a donut in E.coli
o surrounds the lagging strand
o moves in the 3’-5’ direction peeling off the leading strand
10
Q
topoisomerase
A
removes the knots in DNA
o does not travel with the replication fork
11
Q
DNAP III Core
A
- Forms when alpha subunit interacts with other peptides
- Includes epsilon and theta
- Has a high affinity for DNA but falls off after inserting 50 dNTPs on average
12
Q
clamps
A
o Interact with DNAPs to make sure that they don’t fall off during DNA synthesis
• Beta clamp
Shaped like a donut and completely encircles ds-DNA
