Bacterial Genetics & Transformation
description
Transcript of Bacterial Genetics & Transformation
Bacterial Genetics & Transformation
Preparation for the pGlo Lab
Bacterial Genome• Circular• Little protein• Condensed DNA = nucleoid
Mutation as a Source of Genetic Variation
• Bacteria reproduce asexually by binary fission• Mutation can increase genetic diversity when
reproduction rates are high b/c of short generations (fitness)
Genetic Recombination• Combining DNA from two sources • Usually two bacterial cells or bacteria & a phage• http://www.youtube.com/watch?v=MRBdbKFisgI
Conjugation & Plasmids
• Conjugation: Direct transfer of genetic material b/w bacterial cells via a sex pilus that attaches to the recipient
• http://www.biologie.uni-hamburg.de/b-online/library/micro229/terry/images/anim/Fmating.gif
Plasmids
• Small circular piece of DNA, separate from bacterial chromosome can be reversably integrated into the bacteria’s chromosome
• Confer favorable traits
pGLO Bacterial Transformation Lab
• Transform e. coli bacteria• Move genes from one organism to another
with the aid of a plasmid
P GLO Plasmid• pGLO plasmid encodes the gene for GFP and
a gene for resistance to the antibiotic ampicillin
• pGLO gene is turned on (regulated) in the presence of the sugar, arabinose
Gene Regulation
• Not all genes are “on” all the time—why?• Promoter: Located on the DNA template
where RNA polymerase begins transcription of Mrna
• Operon: A cluster of genes controlled by a single promoter
Arabinose Operon
• Bacteria produce three enzymes (araB, araA and araD) to break down arabinose sugar
• The “ara” genes are clustered together and controlled by a single promoter (Pbad).
Expression of Green Fluorsecent Protein
Predict Which Plates Will Glow