What are the steps involved in DNA replication ?
Biology · High School · Tue Nov 03 2020
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DNA replication is a crucial process in which a cell creates an identical copy of its entire DNA. The steps involved in DNA replication are:
1.Initiation: DNA replication begins at specific sites on the DNA molecule called origins of replication. Enzymes, including helicase, unwind and separate the two strands of the DNA double helix, creating a replication fork.
2.Primer Synthesis: Short RNA primers are synthesized by the enzyme primase. These primers provide a starting point for DNA polymerase to begin synthesizing new DNA strands.
3.DNA Polymerization: DNA polymerase synthesizes new DNA strands by adding complementary nucleotides to the template strands. It elongates the DNA strands in a 5' to 3' direction by adding nucleotides to the 3' end of the growing chain.
Two types of strands are synthesized during replication:
- Leading Strand: Synthesized continuously in the 5' to 3' direction toward the replication fork.
- Lagging Strand: Synthesized discontinuously in short segments called Okazaki fragments in the 5' to 3' direction away from the replication fork.
5.Okazaki Fragment Processing: DNA polymerase synthesizes short Okazaki fragments on the lagging strand. DNA ligase joins these fragments by forming phosphodiester bonds, creating a continuous strand.
6.Proofreading and Repair: DNA polymerases have proofreading abilities to detect and correct errors that occur during replication. Other repair mechanisms in the cell ensure accurate replication and fix any mistakes or damaged sections in the newly synthesized DNA.
7.Termination: Replication proceeds bidirectionally until the entire DNA molecule is replicated. The process continues until it reaches termination points, completing the synthesis of two identical DNA molecules.
DNA replication ensures accurate transmission of genetic information from one generation of cells to the next during cell division. The process is highly regulated and essential for the growth, development, and functioning of living organisms.