1. Initiation: The process begins when an enzyme called helicase breaks the hydrogen bonds between complementary DNA strands. This unwinds the DNA double helix and creates two single-stranded DNA molecules. Each of these strands serves as a template for replication.
2. Primer Synthesis: Before replication can begin, short pieces of RNA called primers must be synthesized. Primers are complementary to the template strand and provide a starting point for DNA polymerase, the primary enzyme involved in DNA replication.
3. Elongation: DNA polymerase binds to the template strand and begins to add nucleotides (the building blocks of DNA) one by one. It matches each incoming nucleotide with its complementary base on the template strand, following the base-pairing rules (adenine with thymine and guanine with cytosine). This process continues, and new DNA strands are synthesized in the 5' to 3' direction.
4. Termination: DNA polymerase extends the new DNA strand until it reaches a termination signal or the end of the template strand. Once elongation is complete, the newly synthesized DNA strand is released, and the replication process is repeated on the other template strand.
5. Proofreading: As DNA replication proceeds, it is essential to ensure that errors are minimized. DNA polymerase has proofreading capabilities and can correct any incorrect nucleotide insertions. It removes mismatched nucleotides and replaces them with the correct ones, maintaining the fidelity of DNA replication.
6. Ligation: After replication, there may be gaps or nicks between the newly synthesized DNA fragments. These gaps are filled in by another enzyme called ligase. Ligase joins the fragments together, creating a continuous and complete DNA molecule.
Once DNA replication is complete, there are now two identical copies of the original DNA molecule. Each daughter cell receives one of these copies during cell division, ensuring that genetic information is passed on accurately to future generations of cells.
