DNA helicase

Definition

DNA helicase is an essential enzyme that unwinds the double-stranded DNA helix during DNA replication. By breaking the hydrogen bonds between the nucleotide base pairs, it allows each strand to separate and serve as a template for the synthesis of new DNA strands. This process is crucial for prokaryotic cell division, as it ensures that each daughter cell receives an accurate copy of the genetic material.

5 Must Know Facts For Your Next Test

1. DNA helicase works in both directions along the DNA molecule to ensure efficient unwinding of the double helix.
2. This enzyme requires energy, usually derived from ATP hydrolysis, to perform its function of unwinding DNA.
3. In prokaryotic cells, helicase functions as part of a larger complex, including other enzymes and proteins that are involved in DNA replication.
4. The action of DNA helicase is crucial for preventing tangles and knots in the DNA strands that could interfere with replication.
5. Mutations in the genes encoding helicase can lead to problems in DNA replication, resulting in genomic instability and diseases like cancer.

Review Questions

• How does DNA helicase contribute to the process of DNA replication in prokaryotic cells?
  • DNA helicase plays a critical role in DNA replication by unwinding the double-stranded DNA helix, allowing the two strands to separate. This unwinding is essential because each single strand then serves as a template for new DNA synthesis. Without helicase, the strands would remain coiled together, making it impossible for the replication machinery to access the genetic information needed to duplicate the DNA accurately.
• What would be the consequences of a malfunctioning DNA helicase during prokaryotic cell division?
  • If DNA helicase malfunctions during prokaryotic cell division, it would lead to incomplete or incorrect unwinding of the DNA strands. This could cause difficulties in synthesizing new DNA, ultimately resulting in failure to properly duplicate the genetic material. Such issues could lead to cell division errors, genomic instability, and potentially cell death or malfunction.
• Evaluate the significance of ATP hydrolysis in the function of DNA helicase during prokaryotic cell division and its broader implications for cellular health.
  • ATP hydrolysis is vital for the function of DNA helicase as it provides the necessary energy to break hydrogen bonds between base pairs and unwind the double helix. This energy-driven process ensures efficient and accurate replication of DNA, which is crucial for cellular health. Any disruption in this energy supply could compromise DNA replication fidelity, leading to mutations and potentially resulting in diseases such as cancer or genetic disorders. Therefore, understanding this relationship emphasizes the importance of energy metabolism in maintaining genomic integrity.

Related terms

DNA polymerase:

An enzyme that synthesizes new DNA strands by adding nucleotides complementary to the template strand during DNA replication.

Origin of replication:

The specific location on the DNA molecule where replication begins, marked by specific sequences recognized by initiator proteins.

Okazaki fragments:

Short segments of newly synthesized DNA on the lagging strand during DNA replication, which are later joined together by DNA ligase.