Biochemistry Notes > Queen Mary, University Of London Biochemistry Notes > Genes and Bioinformatics Notes

Replication And Integration Of Phage Dna Notes

This is a sample of our (approximately) 3 page long Replication And Integration Of Phage Dna notes, which we sell as part of the Genes and Bioinformatics Notes collection, a First (78%) package written at Queen Mary, University Of London in 2013 that contains (approximately) 37 page of notes across 19 different document.

Learn more about our Genes and Bioinformatics Notes

Replication And Integration Of Phage Dna Revision

The following is a plain text extract of the PDF sample above, taken from our Genes and Bioinformatics Notes. This text version has had its formatting removed so pay attention to its contents alone rather than its presentation. The version you download will have its original formatting intact and so will be much prettier to look at.

Circularisation of DNA: Lambda DNA circularises after infection, so genes form a single transcriptional unit. Cos elements, or cohesive ends, are 5' overhangs located on linear DNA that are complementary to one another. By forming base pairs between single-stranded ends, linear DNA molecule can circularise.

DNA Replication during Lytic Cycle: Bidirectional/Theta (th) replication Circularised DNA required. Replication begins at specific site, produces two replication forks, which move in opposite directions around DNA circle and meet at opposite sides. Function is to increase templates available for transcription for next stage of replication. Rolling circle replication Generates long concatemers required to package DNA into phage head. Begins with nick/
single-stranded break (SSB) at origin. 5' end displaced from the strand. Using unnicked (3' end) strand as a template, DNA polymerase replicates around DNA molecule, displacing the nicked strand as single-stranded DNA. Multiple copies made, all joined together.

Packing of DNA in phage head Long concatemers cut at cos sites by phage encoded nuclease to generate singlestranded 5' ends. Enzyme only works on double cos sites (only found in concatemers) and makes overhangs complementary. Tail added to packaged phage head.

****************************End Of Sample*****************************

Buy the full version of these notes or essay plans and more in our Genes and Bioinformatics Notes.