Final answer:
DNA helicase is the enzyme responsible for 'unzipping' DNA by breaking hydrogen bonds during replication. These bonds are weak, enabling the separation of DNA strands to serve as templates for new DNA synthesis.
Step-by-step explanation:
The enzyme responsible for 'unzipping' the DNA during the process of replication is known as DNA helicase. This enzyme initiates the replication process by breaking the hydrogen bonds between the base pairs of the DNA double helix. Once these bonds are broken, the two strands are separated, allowing each strand to serve as a template for the formation of new DNA strands.
The hydrogen bonds are weak compared to covalent bonds, yet they cumulatively provide enough strength to hold the two strands of the DNA double helix together. However, the relative weakness of hydrogen bonds is precisely what allows the DNA strands to be separated easily during replication.
As DNA helicase unwinds the DNA, it breaks the hydrogen bonds, and DNA binding proteins then stabilize the unwound strands to prevent premature reannealing. Additional enzymes such as topoisomerases alleviate the tension due to winding/unwinding and reseal any breaks. Following initiation, DNA polymerases play a key role in elongating the new strands by adding nucleotides in a sequence complementary to the parental DNA template.