Unit 2: DNA Replication

Question 1

DNA replication in vivo

Answer 1

• DNA replication inside an organism

Question 2

What are the key features of DNA polymerase (3)

Answer 2

• reads the template DNA strand 3’ to 5’
• makes new complementary strand 5’ to 3’
• requires a free 3’ OH group on the end of an existing DNA strand (like a primer) to start

Question 3

semi-conservative replication

Answer 3

• each daughter cell receives one strand of DNA from the parent and the second is freshly synthesized

Question 4

DNA polymerization

Answer 4

• incoming nucleotides are accepted if they correctly base pair with the template
• the 3’ OH of the growing strand attacks the high energy phosphate bond of the incoming nucleotide, providing energy to drive the reaction

Question 5

origin of replication in circular DNA

Answer 5

• OriC, where replication begins in circular DNA until both directions meet up

Question 6

origin of replication in linear DNA

Answer 6

• OriR, multiple origins as linear DNA is very large

Question 7

rate of replication

Answer 7

• 1000 bps/s

Question 8

How does DNA replication separate strands?

Answer 8

• helicase unwinds the strand a bit at a time and the topoisomerase relieves the stress caused by helicase

Question 9

How does DNA replication create primers?

Answer 9

• RNA polymerase called RNA primase does not need a primer in order to make RNA so the cell uses RNA primers for DNA priming of replication