Which enzyme unwinds the double helix during DNA replication?

Study for the Biology Marking Period 2 Test. Ace your exam with our comprehensive review featuring flashcards and multiple choice questions, all with detailed hints and explanations. Prepare thoroughly and succeed.

Multiple Choice

Which enzyme unwinds the double helix during DNA replication?

Explanation:
Unwinding the DNA double helix at the replication fork is done by DNA helicase, a motor protein that uses energy from ATP to break the hydrogen bonds between base pairs. This separation is what exposes the two template strands so they can be copied by DNA polymerase. Helicase sits at the fork and moves along the DNA, creating the open single strands that replication needs. The other enzymes have different jobs: RNA polymerase makes RNA (in replication, primase—a related enzyme—lays down RNA primers to start synthesis), DNA ligase seals the gaps between newly formed DNA fragments, and DNA topoisomerase relieves the twisting tension ahead of the fork. So the enzyme responsible for unwinding is DNA helicase.

Unwinding the DNA double helix at the replication fork is done by DNA helicase, a motor protein that uses energy from ATP to break the hydrogen bonds between base pairs. This separation is what exposes the two template strands so they can be copied by DNA polymerase. Helicase sits at the fork and moves along the DNA, creating the open single strands that replication needs. The other enzymes have different jobs: RNA polymerase makes RNA (in replication, primase—a related enzyme—lays down RNA primers to start synthesis), DNA ligase seals the gaps between newly formed DNA fragments, and DNA topoisomerase relieves the twisting tension ahead of the fork. So the enzyme responsible for unwinding is DNA helicase.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy