DNA Replication | Molecular Basis of Inheritance | Biology | Khan Academy
Khan Academy India - English・11 minutes read
DNA replication before cell division is crucial to ensure daughter cells receive the correct amount of DNA. It occurs in the S phase of the cell cycle in the interface, involving enzymes and molecules, with Helicase unwinding the helix and Topoisomerase preventing supercoiling.
Insights
- **DNA replication before cell division ensures accurate distribution of genetic material:** The process of DNA replication, occurring during the S phase of the cell cycle, involves enzymes like helicase and topoisomerase to unwind and protect DNA strands, ensuring daughter cells receive the correct genetic information.
- **Significance of multiple origins of replication and replication forks:** Efficient DNA replication in organisms like humans relies on the presence of multiple origins of replication and replication forks, essential for the accurate and timely synthesis of new DNA strands during cell division.
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Recent questions
What is DNA replication?
DNA replication is the process where a cell makes an identical copy of its DNA before cell division. This ensures that each daughter cell receives the correct amount of genetic material.
When does DNA replication occur?
DNA replication occurs during the S phase of the cell cycle, which is part of the interphase. This is when the cell prepares for division by duplicating its DNA.
How does DNA replication start?
DNA replication starts with helicase, an enzyme that unwinds the double helix structure of DNA and separates the two strands. This creates a replication fork where new DNA strands can be synthesized.
What is the role of topoisomerase in DNA replication?
Topoisomerase is responsible for preventing supercoiling of DNA strands during replication. It helps relieve the tension that builds up as the DNA helix unwinds.
Why are multiple origins of replication important?
Multiple origins of replication are crucial for efficient DNA replication in organisms like humans. They allow for replication to occur simultaneously at different points along the DNA strand, speeding up the process.
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Summary
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"DNA Replication: Ensuring Accurate Cell Division"
- Before cell division, DNA replication is crucial to ensure daughter cells receive the correct amount of DNA.
- DNA replication occurs in the S phase of the cell cycle within the interface, involving enzymes and molecules.
- DNA is a double helical structure with two strands running in opposite polarities.
- Replication involves separating the two strands for synthesis of new strands, as shown in Meselson and Stahl's experiment.
- Helicase initiates the process by unwinding the helix and separating the strands.
- Topoisomerase prevents supercoiling of DNA strands during replication.
- Single-stranded binding proteins protect the vulnerable single DNA strands from degradation.
- Multiple origins of replication and replication forks are essential for efficient DNA replication in organisms like humans.
