BIOD 210 Module 4 Bacteria and Bacteriophages (Portage learning)

Why are bacteria an excellent tool for genetic research? -Grow extremely quickly -Very easy to isolate one species or strain of bacteria, typically through the selection of antibiotic-resistant strains -Bacteria can be grown in almost any laboratory, typically with little risk, and their source of nourishment is extremely inexpensive 2. Spontaneous mutation Refers to the process by which bacteria undergo random mutations, some of which may be advantageous to survival in an otherwise hostile environment 3. Example of spontaneous mutation E. coli is sensitive to the bacteriophage T1. When T1 invades a bacterial cell to reproduce, it lyses the cell as it releases its progeny. Therefore, a plate of E. coli that is treated with the T1 phage will be almost entirely lysed except for a few colonies that survive the infection and can grow on the plate. If these bacteria are isolated and grown, it will most likely be observed that they have developed a resistance to the T1 infection through mutation. 4. Selection Involves choosing bacterial colonies in conditions where the desired mutation grows but the wild-type does not. Makes mutations in almost any desired gene possible 5. Minimal medium Medium in which bacteria can synthesize all of the necessary organic compounds needed to sustain themselves 6. Prototrophic Refers to bacteria that can grow on minimal media (do not need additional nutrients or reagents to grow) 7. Logarithmic (log) phase The portion of a bacterial growth curve during which active growth leads to a rapid rise in cell numbers 8. stationary phase stage where the number of bacterial cells in the medium is not actively increasing