DNA Replication Copying the genetic code DNA Replication

DNA Replication Copying the genetic code

DNA Replication Copying the genetic code § Unpack the Chromosomes § Unzip the DNA § Base pairing at the replication fork § Leading strand vs Lagging strand

Making Copies

Making Copies

copied copy during cell division Sister Chromatids (identical copies)

(deactivated or mitotic) inactive DNA Accessing the DNA in use

Accessing the DNA

DNA Structure

Complementary Base Pairing

Complementary Base Pairing

Identical Parent and Daughter Strands

Replication Bubbles 3’ 5’ 3’ helicase 5’

Replication Bubbles 5’ 3’ 3’ 5’

Replication Bubbles 5’ 3’ 3’ 5’

Replication Bubbles Replication Fork 3’ 5’ copies 3’ 5’ Replication Fork

Replication Bubbles

Releasing the Tension

Releasing the Tension § Topoisomerase cleaves and uncoils DNA ahead of helicase § Single-stranded DNA binding proteins (SSB) prevent DNA from coiling back up

DNA Replication Primase 5’ 3’ DNA Polymerase III RNA primer 3’ 5’

DNA Replication 5’ 3’ Leading Strands 3’ 5’ § The leading strands grow toward the replication fork

DNA Replication 5’ 3’ 3’ 5’

DNA Replication 5’ 3’ Lagging Strands 3’ 5’ § The lagging strands grow away from the replication fork

DNA Replication DNA Ligase DNA Polymerase I 5’ 3’ 3’ 5’

DNA Repliaction 5’ 3’ 3’ 5’