Question

The labels for ten bacterial strains were mixed up and now you do not know the identity of each strain. You know all strains are auxotrophs and each one has a single, unique mutation. You set up pairwise crosses between bacterial strains and select for exconjugants by plating on MM. Use the information below to determine F-, F+, and Hfr strains. (- means no colonies grow on MM after conjugation, + means few colonies, +++ means many colonies) Please Explain why F- strains: A1, A2, B5 F+ strains: A3, A4, B3, B4 and Hfr strains: B1, B2, A5 B1B2B3B4B5 A1++++++++- A2++++++++- A3----+ A4----+ A5----+++ F- strains: ______________ F+ strains: _________________ Hfr strains:

Answer 1

As auxotrophs are mutants organism which requires particular additional nutrients which normal strains can not,

Hfr A high-frequency recombination cell (Hfr cell) (also called an Hfr strain) is a bacterium with a conjugative plasmid (for example, the F-factor) integrated into its chromosomal DNA

F+have fertity factor and are considered to be inheritable( male) while female have non and do not make pill for conjugation

**The qn is incomplete