Final answer:
Helicase is the enzyme responsible for unzipping DNA by breaking hydrogen bonds between strands during replication, enabling each strand to be used as a template for new DNA.
Step-by-step explanation:
The molecule responsible for 'un-zipping' DNA during replication is an enzyme called helicase. This enzyme systematically breaks the hydrogen bonds between the two strands of DNA, allowing them to separate and serve as templates for the creation of new strands. The process begins during the initiation stage of DNA replication, where helicase plays a crucial role. It's also important to note that topoisomerase enzymes work alongside by relieving any supercoiling that might occur as the DNA unwinds, ensuring that the replication process proceeds smoothly.