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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
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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
ArabinoseOperon • 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).