BIOL431 Lecture Notes - Lecture 4: Lambda Phage, Regulon, Repressor Lexa

• School: University of Waterloo
• Department: Biology
• Course: BIOL431
• Professor: Michael Lynch

Document Summary

2: most won"t show growth but some colonies might = jackpot. Incorrect assumption: any pressure on the plate won"t affect the outcome (mutations won"t arise in response to that selective pressure but mutations do arise in the absence of selective pressure) Selective pressure here: bacteriophage = bactericidal effect where they infect & lyse the cells so the bacteria can"t mutate fast enough. Better way to test if selective pressure can cause a mutation to said selection = bacteriostatic (stops growth, won"t kill them) by limiting a metabolic component (auxotrophs > phototrophs due to missing aa or carbon/nitrogen source) 1: master plate with a lawn of bacteria that are antibiotic sensitive (wild type strain, no antibiotic on plate) 2: imprint the plate onto the velvet so you copy the lawn. 3: transfer & incubate onto media plates both with and without antibiotic. 4: colony growth on antibiotic plate = antibiotic resistant.