Consider an experiment in which an Hfr strain of E. coli bacteria with the StrS, his+, met + alleles in its genome is mixed with an F - strain of E. coli with the StrR, his-, and met - alleles in its genome. After the cells have been cultured together for 8 hours, the mixture of cells is plated on minimal media containing Streptomycin.

1. Which genotype do you expect to be most common among the colonies that grow?

O F+: StrR, his + and met+

O F-: StrR, his - and met-

O Hfr: StrR, his + and met+

O F-: StrR, his + and met+

O F+: StrR, his - and met-

Question

Biology

Bryan Good

5 February, 19:33

Consider an experiment in which an Hfr strain of E. coli bacteria with the StrS, his+, met + alleles in its genome is mixed with an F - strain of E. coli with the StrR, his-, and met - alleles in its genome. After the cells have been cultured together for 8 hours, the mixture of cells is plated on minimal media containing Streptomycin.

1. Which genotype do you expect to be most common among the colonies that grow?

O F+: StrR, his + and met+

O F-: StrR, his - and met-

O Hfr: StrR, his + and met+

O F-: StrR, his + and met+

O F+: StrR, his - and met-

+3

Answers (1)

Know the Answer?

Samantha · Answer 1

F-: StrR, his + and met+

Explanation:

Since it is stated that the minimal media contains Streptomycin, therefore:

a.) To be able to grow on this media, the E. coli genome must have StrR allele.

b.) Also remember that only prototrophs can grow on minimal media, thus colonies with mis + and met + (which are prototroph) will be the common growth.

c.) In the conjugation of F - strain with an Hfr strain, F - which contains the StrR allele do not and cannot form F + or Hrf strains but remains F-