The action of helicase creates ??,
DNA fragments and replication bubbles
primers and DNA fragments
primers and replication bubbles
replication forks and replication bubbles
DNA fragments and replication forks
The correct answer and explanation is:
The correct answer is:
replication forks and replication bubbles
Explanation:
Helicase is an essential enzyme in DNA replication. Its primary role is to unwind and separate the double-stranded DNA (dsDNA) into two single strands. This separation is crucial because the two strands of the DNA molecule serve as templates for the synthesis of new complementary strands.
Here’s how helicase contributes to the process:
- Formation of Replication Bubbles: During DNA replication, the helicase enzyme binds to the origin of replication, a specific sequence of DNA. It starts unwinding the DNA in both directions, creating a region where the double-stranded DNA is separated into two single strands. This unwound region forms a “replication bubble.” As helicase continues to unwind the DNA, the replication bubble expands in both directions, allowing the DNA to be copied simultaneously at multiple locations along the DNA molecule.
- Formation of Replication Forks: At the boundaries of the replication bubble, the DNA strands form “replication forks.” These are Y-shaped structures where the DNA is actively being unwound and where the DNA replication machinery (such as DNA polymerase) works to synthesize the new complementary strands. Each replication fork consists of a leading strand, which is synthesized continuously, and a lagging strand, which is synthesized in fragments known as Okazaki fragments.
In summary, helicase creates replication forks (where the DNA strands are actively being separated and replicated) and replication bubbles (the overall unwound region where replication occurs). The unwinding process facilitated by helicase is critical for the entire DNA replication process to proceed efficiently and accurately. Without helicase, DNA replication would be impossible, as the DNA strands would remain coiled and inaccessible for copying.