BIOL 209 1st Edition Lecture 18 Outline of Last Lecture I. Question/Answer’sII. Controlling Gene ExpressionIII. SelectionIV. MutationsIV. Counterating MutationsA. ProofreadingB. Repair MechanismsOutline of Current Lecture I. Question/Answer’sII. RecombinationA. ConjugationB. TransformationC. TransductionCurrent LectureI. Question/Answer’sA. What’s a mutagen? Something that will lead to a mutationB. What’s a toxicant? Something that will make you sick, but not necessarily change your genomeC. What repair mechanisms are useful for reducing the frequency of spontaneous mutations? DNA polymerase proofreading (enzymes recognize & go back via excision repair)D. Which is useful for reducing the frequency of induced mutations? Excision repairE. Which identifies a gene transfer mechanism that requires both the donor and recipient cells to be alive at the time of gene transfer? ConjugationF. Which procedure could distinguish gene transfer by transduction and gene transfer by transformation? Treat the mixture of cells with an enzyme that degrades free DNAII. Recombination: conjugation, transformation, and transduction – gene transfer from one bacterial organism to another – homologous recombination requires some similarity between donor and recipient DNA… New cell arises different from donor & original recipient genome… Necessary for maintaining new genome, otherwise DNA transferred will degradeA. Conjugation1. Direct2. Plasmid transferThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.3. F factor encodes information for a conjugated pili that mediates attachment between donor & recipient cellsa. Plasmids are small, circular DNA – AKA F factor, fertility – can have antibiotic resistance, virulence, metabolic functions, etc.4. Conjugation H factor transfer – plasmid DNA is integrated into genome and during conjugation, the donor cell attempts to transfer a copy of entire genome – doesn’t really happena. What happens to the donor DNA that gets transferred? It gets recombined (integrated into the chromosome)B. Transformation1. Indirect2. Griffith’s experiment (ex. of horizontal gene transfer)3. Cells take up free DNA with receptor cells – DNA binding proteins & recombines into competent DNA in the cellC. Transduction1. Indirect2. Bacteriophages pick up viral or host genome parts (random event) and introduce them to a new
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