Question

When HFR conjugates with an F${}^{-}$ bacterium, the

• A. $F^{-}$ cell will convert to $F^{+}$ but always a recombinant
• B. $F^{-}$ cell will convert to $F^{+}$ but always a not recombinant
• C. $F^{-}$ will remain $F^{-}$ and may or may not be a recombhinant
• D. $F^{-}$ will convert to Hfr without recombination

Answer 1

The correct option is A $F^{-}$ cell will convert to $F^{+}$ but always a recombinant

HFR stands for High-frequency recombination cells. HFR cells are those cells which have its plasmid integrated with the chromosomal DNA. Thus, when the bacteria conjugate with the F${}^{-}$ cells, with the F plasmid genes, the genes which are nearer would also get transferred to the F${}^{-}$ cells. This would lead to the formation of the partial diploid condition in the F${}^{-}$ cells as they may have two sets of certain genes. Hence, these cells can have the possibility of recombination between the homologous genes.

Thus, the correct answer is 'F${}^{-}$ cell will convert to FF${}^{+}$ but always a recombinant'.