What is the function of helicase?

What is the function of helicase?

• A. Joins Okazaki fragments
• B. Breaks hydrogen bonds to separate DNA strands
• C. Proofreads the new DNA
• D. Adds nucleotides to the growing strand

Answer: (B)

Unwinding the DNA double helix to create single-stranded templates is the essential step in replication, and helicase does this by breaking the hydrogen bonds between base pairs using energy from ATP. This separation opens up the replication fork so that DNA polymerases can access each strand and synthesize new complementary strands. Other enzymes have different roles: ligase joins Okazaki fragments on the lagging strand; proofreading is done by the polymerase’s exonuclease activity to correct mistakes; and DNA polymerase adds nucleotides to the growing strand.

Unwinding the DNA double helix to create single-stranded templates is the essential step in replication, and helicase does this by breaking the hydrogen bonds between base pairs using energy from ATP. This separation opens up the replication fork so that DNA polymerases can access each strand and synthesize new complementary strands. Other enzymes have different roles: ligase joins Okazaki fragments on the lagging strand; proofreading is done by the polymerase’s exonuclease activity to correct mistakes; and DNA polymerase adds nucleotides to the growing strand.