Here's a breakdown of the key steps involved:
1. Unwinding and Separating the DNA Double Helix: The DNA double helix is unwound and separated by the enzyme helicase. This creates two separate strands, each serving as a template for the new DNA molecule.
2. Primer Binding: Short RNA primers are added to each template strand by the enzyme primase. These primers provide a starting point for DNA polymerase to begin adding nucleotides.
3. Elongation: The enzyme DNA polymerase adds nucleotides to the 3' end of the new DNA strand, using the template strand as a guide. This process is called elongation.
4. Leading and Lagging Strands: Because DNA polymerase can only add nucleotides in the 5' to 3' direction, the new strand is synthesized continuously on one template strand (leading strand). However, on the other template strand (lagging strand), the new strand is synthesized in short fragments called Okazaki fragments.
5. Joining Okazaki Fragments: The Okazaki fragments are joined together by the enzyme DNA ligase, creating a continuous strand of DNA.
6. Proofreading: DNA polymerase has a proofreading function that corrects any mistakes during replication. This ensures the accuracy of the copied DNA.
7. Termination: Once the entire DNA molecule has been replicated, the process is terminated.
Key Enzymes involved in DNA Replication:
* Helicase: Unwinds the DNA double helix.
* Primase: Adds RNA primers to initiate DNA synthesis.
* DNA Polymerase: Adds nucleotides to the new DNA strand.
* DNA Ligase: Joins Okazaki fragments.
Importance of DNA Replication:
DNA replication is essential for cell division. Each daughter cell receives a complete copy of the parent cell's DNA, ensuring genetic continuity.
