DNA replication: Difference between revisions
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== DNA replication<br> == | == DNA replication<br> == | ||
DNA replication | DNA replication is a duplication process where exact copies of DNA within cells are replicated, with very few errors. Errors occur at a rate of 1 in 10<sup>9</sup><sup></sup><sup></sup> bases per replication. In mitotic division, DNA replication occurs during the S phase. DNA must duplicated before the division takes place to main the chromosome number of the two daughter cell. At the end of the division, two genetically identical daughter cells are produced. DNA replication is semi-conservative.<br> | ||
<br> | <br> | ||
== Key Enzymes<br> == | == Key Enzymes<br> == | ||
[[ | [[DNA helicase|DNA Helicase]] - Unzips double stranded DNA by breaking [[Hydrogen bonds|hydrogen bonds]] between base pairs, to allow other enzymes to access bases. <br> | ||
[[ | [[DNA Primase|DNA Primase]] - Catalyses the polymerisation of short RNA strands (primers) which act as a place for DNA Polymerase III to bind and start replication.<br> | ||
[[ | [[DNA Polymerase|DNA Polymerase III]] - Attatches to primers on open DNA strands and builds a complementary strand, Working from the 5' to the 3' end.<br> | ||
[[ | [[DNA polymerase I|DNA Polymerase I]] - Catalyses DNA replication and posesses a 3' to 5' exonuclease activity, which essentially "proof reads" the replication and lowers error rate.<br> | ||
[[ | [[Dna ligase|DNA Ligase]] - Joins deoxyribose backbone in lagging strand.<br> | ||
<br> | <br> | ||
== References<br> == | == References<br> == | ||
<references /><br> | <references /><br> | ||
http://bioteach.ubc.ca/TeachingResources/MolecularBiology/DNAReplication.swf<br> | http://bioteach.ubc.ca/TeachingResources/MolecularBiology/DNAReplication.swf<br> | ||
http://www.promega.com/products/cloning-and-dna-markers/cloning-tools-and-competent-cells/dna-polymerase-i/<br> | http://www.promega.com/products/cloning-and-dna-markers/cloning-tools-and-competent-cells/dna-polymerase-i/<br> | ||
Revision as of 21:34, 1 December 2011
DNA replication
DNA replication is a duplication process where exact copies of DNA within cells are replicated, with very few errors. Errors occur at a rate of 1 in 109 bases per replication. In mitotic division, DNA replication occurs during the S phase. DNA must duplicated before the division takes place to main the chromosome number of the two daughter cell. At the end of the division, two genetically identical daughter cells are produced. DNA replication is semi-conservative.
Key Enzymes
DNA Helicase - Unzips double stranded DNA by breaking hydrogen bonds between base pairs, to allow other enzymes to access bases.
DNA Primase - Catalyses the polymerisation of short RNA strands (primers) which act as a place for DNA Polymerase III to bind and start replication.
DNA Polymerase III - Attatches to primers on open DNA strands and builds a complementary strand, Working from the 5' to the 3' end.
DNA Polymerase I - Catalyses DNA replication and posesses a 3' to 5' exonuclease activity, which essentially "proof reads" the replication and lowers error rate.
DNA Ligase - Joins deoxyribose backbone in lagging strand.
References
http://bioteach.ubc.ca/TeachingResources/MolecularBiology/DNAReplication.swf