DNA REPLICATION


Websites:
http://www.freefever.com/animatedgifs/biology.html
http://www.ncc.gmu.edu/dna/replicat.htm
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/D/DNAReplication.html


DNA replication is a process which occurs during cell division. First, the DNA unravels, through the use of helicase enzymes. There are many other enzymes which are utilized to aid in DNA replication. Single-strand binding (SSB) proteins bind to DNA strands, and allow further stablization. Topoisomerases break the DNA molecules at specific areas, to reduce stress on the configuration of the DNA. The RNA primer signals the beginning of DNA replication, and then the DNA polymerase follows. Due to the DNA polymerase, nucleotides are constantly added, in a complementary fashion. The new DNA strand must be synthesized in the 5’ to 3’ manner.
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There are two essential strands in DNA replication. There is the lagging strand, and the leading strand. The leading strand goes toward the replication fork, which is much quicker and efficient than the lagging strand. However, the lagging strand goes away from the replication fork, thus it is considerably slower. It is synthesized in Okazaki fragments. These separate strands are combined through the
usage of DNA ligase. It is essential to know that DNA synthesis is bidirectional. Some enzymes are used to fix errors in DNA as well.

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http://esg-www.mit.edu:8001/esgbio/dogma/repl.html
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http://upload.wikimedia.org/wikipedia/commons/thumb/7/70/DNA_replication_split.svg/297px-DNA_replication_split.svg.png