gel electrophoresis

gel electrophoresis

separates different molecules to analyse different proteins and DNA

general process

place mixture of molecules in agarose gel and apply an electric field

factors affecting movement speed of molecules

net charge of particles, size of molecules and gel composition or pore size

protein electrophoresis

seperates polypeptides produced by different alleles of many genes

protein charge

dependant on ionisation of the R groups on the amino acid residues

protein pH

charge is dependant on pH and is regulated via buffer solution

protein charge seperation

usually negatively charge…seperate due to different net charges

DNA electrophoresis

region of DNA is chosen via VNTR

VNTRs

variable number tandem repeats

DNA preperation

DNA is chopped using restriciton endonucleases and placed on absorbent paper into gel and then heated to separate strands

probes

short sequences of single stranded DNA…contain radioactive isotopes which allow for seperated fragments to be visible