DNA Replication

http://serc.carleton.edu/microbelife/research_methods/genomics/replication.html

Summary:

        DNA replication is a process when one strand of DNA makes an identical copy of its own DNA. We all know that DNA stores genetic info, and 1 strand of DNA is a double helix with 4 nucleotide base pairs: A,C,G, and T. We know that A pairs with T and C pairs with G. In DNA replication, DNA produces an identical copy of DNA. First, the enzyme 'helicase' splits the double helix in half, breaking the hydrogen bonds between base pairs and separating them from each other. We know that the sugar phosphate-backbones run in opposite directions (antiparallel), and one backbone runs in 5' to 3', and the other one runs in 3' to 5'. A new strand can only be created from the backbone running in 5' to 3'. After the splitting of the double helix, DNA polymerase comes in and creates complementary strands for each backbone (for 5', a 3' is created, and for a 3', a 5' is created). DNA polymerase also creates complementary base pairs between the 2 setes of backbones. on the old 3' backbone, several okazaki fragments are created and connected by DNA ligase, which also connects the base pairs to the backbones. After this, DNA polymerase checks for errors, and if any, repairs them. Finally, 2 identical DNA strands are created. Each DNA strand has one new backbone and one old backbone. DNA replication is necessary for cell division, in which 2 daughter cells need 2 identical copies of DNA when a parent cell splits.

Relevance to Class:    

        In term 2, we all studied how DNA can duplicate itself and produce its own identical copy. We learned about DNA polymerase, antiparallel backbones (3' and 5'), 4 nucleotide base pairs, and how they all connect in the process of DNA replication. In the class notes, we studied the DNA structure (4 base pairs A,T,C,G and sugar phosphate-backbones). We learned that in a DNA strand,  A pairs with T and C pairs with G, and how DNA is a double helix (2 strands wrapped around each other). This was all included in the Molecular Genetics Unit in term 2, which is right before the Evolution of Life unit.

Information:
URL: http://serc.carleton.edu/microbelife/research_methods/genomics/replication.html
Date modified: 1-9-13
Author: N/A

By: Hemanth Katragadda