In an experiment, E. Coli that are auxotrophic for methionine, tryptophan, and adenine biosynthesis are grown...

In an experiment, E. Coli that are auxotrophic for methionine, tryptophan, and adenine biosynthesis are grown on petri dishes containing rich media with all of these nutrients. The bacteria grow into normal colonies. The same bacteria are plated onto media that is lacking those 3 nutrients (minimal media) and no growth is observed. A second strain of E. Coli which is auxotrophic for histodine, and leucine is also able to grow on rich media but not minimal media. After mixing the two strains together for a period of time some colony growth is now onserved on minimal media.

-Provide a likely explanation for what has happened. -Explain the individual steps of the process.

In a second experiment, strain 1 is killed using a lysis buffer, and the lysate is mixed with strain. After incubating for a period of time the cells are plated onto minimal media and some growth is observed.

-Provide a likely explanation for what has happened.

Solutions

Expert Solution

1) strain 1 of E Coli - auxotrophic for methionine, tryptophan, and adenine biosynthesis . They can grow only media containing rich with all of these nutrients. The bacteria grow into normal colonies. No growth observed in petri plate where the nutrient are absent.

Strain second is auxotrophic for histidine or leucine.

But when these stain are mixed together for a period of time , they can grow on minimal media .

This is due to the transfer of genetic material of strain 1 in to stain 2 bacteria via conjugation tube. It's a style of sexual reproduction in bacteria where genome of one bacteria is transferred to another bacteria . After this genome is inserted in to bacterial genome by a process of recombination thus it resume capacity to grow in minimal media.

2) here bacteria are not incubated with each other. Strain 1 is lysed and lysate is incubated with second stain. Here lysate contain DNA of strain 1 when these DNA contsjng lysate incubated with second strain. By the transformation process second strain uptake bacteria 1 DNA from lysate . And after uptake, by the process of recombination some bacteria generated having all the genes and grow on minimal media.

gladiator answered 1 year ago

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