DNA Replication Initiation and Termination Flashcards Preview

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Flashcards in DNA Replication Initiation and Termination Deck (11):
1

Where replication starts

origin of replication
A-T rich regions, easier to open

2

once DNA strands are separated, this area is called

replication bubble

3

bacteria have how many origins?

1 origin
takes 30-40 minutes to duplicate genome

4

how is bacterial initiation regulated

only initiates when sufficient nutrients are available
hemimethylation of newly synthesized DNA

5

what initiates bacterial DNA replication

initiator protein binds to origin of replication

6

eukaryote origin of replication

multiple origins of replication,
activated in clusters called Replication Units

7

DNA replication occurs in what phase

S phase only

8

eukaryotic origin licensing

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

9

Bacteria DNA replication termination

Tus-Ter complex blocks the helicase and terminates replication

10

telomeres have a repetitive sequence

G-rich sequences GGGTTGG

11

extends the telomeres

telomerase, carries its own RNA template
elongates DNA in 5'-3' direction, leaves longer 3' end