Replication
Replication is the process by which DNA copies itself. It occurs during the S Phase of cell division. This process produces an exact copy of a section of DNA and can take place on multiple points along the molecule.
The first chemical that helps with the process is called Helicase. This chemical breaks the hydrogen bonds connecting the bases and causes the helix to unwind. Then, another compound called DNA Polymerase moves along the molecule and substitutes in complementary base pairs for each strand of DNA forming two DNA molecules from one that are identical. A proofreading molecule then moves along the DNA and substitutes in any strands that were incorrectly placed during replication. For example, if a Cytosine base were substituted in as the complementary partner of an Adenine base instead of a Thymine, the Cytosine would be removed and a Thymine added in its place. Then, helicase again forms the hydrogen bonds between the DNA strands and re-winds the DNA structure to form the double helix. This process ensures that an exact copy of DNA is passed on ot each new succession of cells produced. |
Attribution: Madprime @ en.wikipedia.org. Used under creative commons with permission. |