Question

What occurs when a $F^{+}$ bacterium conjugates with $F^{–}$ bacterium?

• A. $F^{+}$ gets modified into $F^{–}$
• B. $F^{–}$ gets modified into $F^{+}$
• C. $F^{–}$ gets modified into $F^{–}$
• D. Hfr gets modified into $F^{-}$

Answer 1

The correct option is B $F^{–}$ gets modified into $F^{+}$

Bacteria carrying the F plasmid (fertility plsamid) are designated $F^{+}$ and those lacking it are designated as $F^{-}$. $F^{+}$ and $F^{-}$ cells can conjugate. When conjugation occurs, the $F^{+}$ cells can act as F donors. The F plasmid DNA replicates and the newly synthesized copy of F molecule is transferred to the $F^{-}$ recipient. However, a copy of the plasmid always remains in the donor cell. The recipient cell, after procuring the F plasmid, gets converted into $F^{+}$. The transfer of the F plasmid from $F^{+}$ to $F^{-}$ is so rapid that the F plasmid can spread like wildfire from strain to strain throughout a bacterial population.