Dna replication D1.1

HL BIO

Step 1

DNA Helicase unwinds the double helix and breaks the hydrogen bonds between complementary strands *3,8

Step 2

1. Gyrase will stabilize the DNA and with single stranded binding proteins will hold the DNA open for replication 

Step 3

DNA primase adds RNA primer to both strands *8

Step 4

DNA polymerase III adds DNA nucleotides starting at the primer using complementary base pairing rules reading 3’ to 5’ and building 5’ to 3’ *3,6,8

Step 5

1. DNA polymerase I removes the RNA primer and replaces it with DNA nucleotides *8 

Step 6

1. DNA ligase glues fragments of DNA together by forming covalent bonds along the phosphodiester backbone 

Step 7

The end result is two double strands formed semiconservatively (half old and half new)

What happens to the leading strand

Formed continuously

Lagging strand

1. formed in Okazaki fragments that must be glued together by ligase