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Unformatted text preview: 2 3 4 5 6,7 Bacterial Genetics Why Study Bacteria?- It is simpler, easier to study- DNA can be manipulated Manipulated to produce things like insulin- If we get to understand bacteria more, we can help fight the pathogenic kinds Culturing Bacteria- Different mediums to culture bacteria with: Broth Includes: o Water o Carbon Source: Usually glucose o Salts: These are used to get the elements Good for quick growth Not good for selection Cannot select a particular bacteria Agar Contains broth solution, along with the agar: o Preparation Add it to a powder as a hot liquid: while its still hot, you can pour it into a form and as it cools, it turns into a semi-solid Then take a small amount of bacteria and spread it onto the surface o Advantages for the semi-solid state Allows nutrients and wastes to diffuse Allows the bacteria to land as individuals on the broth This is especially good because they cant move o Then, as they grow and divide, colonies form o Theyre identical because they came from the asexual reproduction of one cell. This allows us to choose the bacteria we want Once weve chosen the bacteria we want to produce, put it into broth To grow this bacteria rapidly- Strains of bacteria: Strains are like breeds, different varieties between a species Their strains have different alleles at their genes Different phenotypes One can distinguish between different strains by growing in different media Different types: Wild-type Strain/Allele These are the most common Have functional alleles In terms of media, the wild- type strain can grow on the simplest type of media for that speicies minimal media Metabolism helps wild-type bacteria make own amino acids. Biochemical pathway of functional alleles catalyzing functional enzymes Prototrophic Strain o Can live and grow on minimal media o All wild-type strains are prototrophic o But, not all prototrophic strains are necessarily wild-type o So, the strain has some wild-type , but not all Auxotrophic Strain o Cannot live on minimal media , it dies o It has an error of Anabolism (building up): Pathways that start with little, basic components and build more complicated ones o Therefore, one of these pathways is non-functional: Cannot make an amino acid, vitamin, etc Carbon-Source Mutant o This has an error of Catobolism (breaking down) It cannot break down a particular carbon source (a sugar, but not glucose) o A break down of a carbon source(a sugar) provides carbon and energy to use for other things o However, this cannot be a glucose mutant Most cells use glucose whenever possible Cells that dont use glucose die Glucose metabolism is central to metabolism Most cells are able to break down other sugars Since this cell cannot break one of the other sugars, it is a carbon source mutant to some particular kind of sugar Antibiotic Resistant/Sensitive Strains...
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