GENE20001 Lecture Notes - Lecture 17: Replica Plating, Auxotrophy, Genetic Variation
Document Summary
Temperature sensitive mutants e. g. grows at 30 c (even on ampicillin) but not at 37 c. Auxotrophic mutants e. g. unable to grow in the absence of tryptophan. Most bacterial species can grow on very simple defined medium (minimal medium) as they are capable of synthesizing all of the complex biomolecules that they require. A simple source of carbon and energy such as glucose. A simple source of nitrogen such as ammonium (nh4. From these basic components complex molecules such as nucleic acids (dna and rna), amino acids (proteins) and complex carbohydrates (cell wall) can be synthesized. From these most bacteria can build everything they need. Auxotrophs: mutants which can no longer grow on minimal medium but can grow on rich medium. A rich medium normally has a mixture of yeast extract and other hydrolysed substrates, such as casein. It contains all of the basic amino acids, lipids, nucleosides and vitamins. Isolated and identified by a process called screening.
