Unwinding

• DNA helicase separates the double stranded DNA into single strands, by breaking the hydrogen bonds between the nitrogen base pairs.
• Two replication forks within the DNA are created. Topoisomerase relaxes supercoiling in front of the replication fork.
• The separated parental strands may now act as templates.
• Single stranded binding proteins attach to the strands preventing them from reforming the double helix.