Replication of DNA
Replication is the process of copying a double-stranded DNA molecule to produce two indentical DNA molecules. DNA replication is one of the most fundamental processes that occurs within a cell.
This can only happen if the DNA in a cell can be perfectly copied before it divides, so that each 'daughter' cell obtains a complete set of identical genetic information.
1. DNA unwinds at the origin of replication.
2. New bases are added to the complementary parental strands.One new strands is made continuosly,
while the other strand is made by pieces.
3. Primers are removed, new DNA nucleotides are put in place of the primers and the backbone is sealed by DNA ligase.
In DNA replication there are 5 important enzymes in the process
Enzymes involved in DNA replication:
~ Helicase: Unwinds the DNA.
~ Primase: synthesize RNA primers.
~DNA polymerase III: Adds nucleotides in the 5' to 3' direction.
~ DNA polymarase I: Replaces RNA primers with DNA
~DNA ligase: Joins Okazaki fragments.
Characteristic of DNA :
- Semi-conservative: Each replicated molecule has one old strand and one new strand.
- Specific Replication: Starts at the point of origin and follows a specific direction.
- High accuracy DNA: Polymerase has proofreading capabilities to minimize errors.
DNA replication is a fundamental process that maintains the continuity of genetic information from generation to generation. Without this process, cells would not be able to reproduce or perform their functions properly. Understanding DNA replication is not only important in molecular biology, but also in medical fields, such as gene therapy and the diagnosis of genetic diseases.
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