DNA Replication Initiation and Termination Flashcards Preview

Molecular Biology > DNA Replication Initiation and Termination > Flashcards

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

Where replication starts

A

origin of replication

A-T rich regions, easier to open

2
Q

once DNA strands are separated, this area is called

A

replication bubble

3
Q

bacteria have how many origins?

A

1 origin

takes 30-40 minutes to duplicate genome

4
Q

how is bacterial initiation regulated

A

only initiates when sufficient nutrients are available

hemimethylation of newly synthesized DNA

5
Q

what initiates bacterial DNA replication

A

initiator protein binds to origin of replication

6
Q

eukaryote origin of replication

A

multiple origins of replication,

activated in clusters called Replication Units

7
Q

DNA replication occurs in what phase

A

S phase only

8
Q

eukaryotic origin licensing

A
  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
Q

Bacteria DNA replication termination

A

Tus-Ter complex blocks the helicase and terminates replication

10
Q

telomeres have a repetitive sequence

A

G-rich sequences GGGTTGG

11
Q

extends the telomeres

A

telomerase, carries its own RNA template

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