5. Genetics of Bacteria and Viruses

What is a plasmid?

True or False:All bacterial cells within a bacteria colony grown on a plate in a laboratory are genetically identical.

Which of the following is NOT a way scientists can phenotypically identify a bacterial mutation?

How do we know that bacteria undergo genetic recombination, allowing the transfer of genes from one organism to another?

How do we know that genes exist in bacteria and bacteriophages?

Fifteen bacterial colonies growing on a complete medium are transferred to a minimal medium. Twelve of the colonies grow on minimal medium.

The serine biosynthetic pathway is a three-step pathway in which each step is catalyzed by the enzyme product of a different gene, identified as enzymes A, B, and C in the diagram below.

Mutant 1 grows only on min + Ser. In addition to growth on min + Ser, mutant 2 also grows on min + 3-PHP and min + 3-PS. Mutant 3 grows on min + 3-PS and min + Ser. Identify the step of the serine biosynthesis pathway at which each mutant is defective.

Fifteen bacterial colonies growing on a complete medium are transferred to a minimal medium. Twelve of the colonies grow on minimal medium.

The three colonies that do not grow on minimal medium are transferred to minimal medium supplemented with the amino acid serine (min + Ser), and all three colonies grow. Characterize these three colonies.