Ch 13

Question 1

template strand

Answer 1

strand that is copied

Question 2

primer strand

Answer 2

complementary DNA strand that is being synthesized

Question 3

DNA occurs in the

Answer 3

5–>3 direction

Question 4

Replication fork

Answer 4

point where both strands are being replicated

Question 5

leading strand

Answer 5

strand is synthesized in a conitnous fashion

Question 6

lagging strand

Answer 6

strand must be synthesized in a discontinuous fashion

Question 7

Replication origin

Answer 7

• 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

Question 8

RNAP vs DNAP

Answer 8

• 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

Question 9

helicase

Answer 9

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

Question 10

topoisomerase

Answer 10

removes the knots in DNA

o does not travel with the replication fork

Question 11

DNAP III Core

Answer 11

• 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

Question 12

clamps

Answer 12

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