How does PCR work? (1 Viewer)

[SadCeliac]

I understand that it replicates DNA/a gene through a cyclic process (Denaturing, Annealing, Something??? --somewhere here DNA is heated and cooled?) but I don't quite know what each stage does / how it actually works. I also know that it needs lots of free nucleotides to work

Also, how would I contrast it with Recombinant Plasmid replication? E.g., for a 3 mark question

 

[SadCeliac]

I understand that it replicates DNA/a gene through a cyclic process

Update: I think this summarises it, but I would like someone's clarification <3

DENATURING >> ANNEALING >> EXTENSION

PCR requirements:
- DNA sample
- primers
- free nucleotides
- Taq polymerase enzyme
- buffer

Process:
- Heat to high temp (95degrees)
- Denaturing occurs (strands separate)
- Cool to lower temp (55 degrees)
- Annealing occurs (primers bind to template DNA)
- Heat slightly (to 72degrees)
- Extension occurs (new strand is synthesised)
- Repeat

 

[Big_Kev]

yep exactly - u can also apply this to Sanger sequencing (the initial steps bcoz DNA must be amplified through PCR) but yuh overall nice

 

[SadCeliac]

yep exactly - u can also apply this to Sanger sequencing (the initial steps bcoz DNA must be amplified through PCR) but yuh overall nice

okok - so literally just

seperate the strands >> add primers >> extend with taq polymerase

 

[SadCeliac]

Gene cloning is faster and more simple. PCR is more expensive and makes more copies.

I would have thought that recombinant gene cloning using plasmids is more complex and slower than PCR?