DNA Replication Initiation and Termination

Question 1

Where replication starts

Answer 1

origin of replication

A-T rich regions, easier to open

Question 2

once DNA strands are separated, this area is called

Answer 2

replication bubble

Question 3

bacteria have how many origins?

Answer 3

1 origin

takes 30-40 minutes to duplicate genome

Question 4

how is bacterial initiation regulated

Answer 4

only initiates when sufficient nutrients are available

hemimethylation of newly synthesized DNA

Question 5

what initiates bacterial DNA replication

Answer 5

initiator protein binds to origin of replication

Question 6

eukaryote origin of replication

Answer 6

multiple origins of replication,

activated in clusters called Replication Units

Question 7

DNA replication occurs in what phase

Answer 7

S phase only

Question 8

eukaryotic origin licensing

Answer 8

1. ORC (origin recognition complex) made of 6 subunits, binds to the origin
2. hexameric MCM helicase (2-7) is loaded by Cdc6 and Cdt1 to form the prereplication complex
3. Cdc6 is phosphorylated, then degraded. ORC is phosphorylated. THIS PREVENTS FIRING AGAIN. INITIATION IS REGULATED

Question 9

Bacteria DNA replication termination

Answer 9

Tus-Ter complex blocks the helicase and terminates replication

Question 10

telomeres have a repetitive sequence

Answer 10

G-rich sequences GGGTTGG

Question 11

extends the telomeres

Answer 11

telomerase, carries its own RNA template

elongates DNA in 5’-3’ direction, leaves longer 3’ end