Biology 1002B Chapter Notes - Chapter 12: Citric Acid, Escherichia Coli, Operon
24 Apr 2016
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Heterotrophic growth, colony of e. coli, no photosynthesis, must be reduced carbon used for growth. Cells contain glucose, growth media also contains citrate (fe-citrate). Citrate is required because it keeps iron in solution, required for e. coli to survive. Citrate not used to metabolism, but to keep iron. Shake cells on shaker, to create lots of oxygen, they are not anaerobic. Cells will suck it all in, after 8 hours, cells have stopped growing. Sit for 16 hours until you subculture again. Evolution is about adapting to specific circumstances, and filling niches. If the cell could develop a way to use citrate. Huge selective advantage of mutation occurring to be able to use citrate, which no one is using. The generations increase and become able to have higher density, then plateaus. Cit+ phenotype allows for an increased culture density after the presence of glucose has depleted. Cit+ allows for the e. coli to use citrate as an energy source/carbon source, by magic.
