Two bacterial populations were prepared in a laboratory. Population A expresses the wild-type regulator protein that controls the transcription of gene X. Population B contains a mutation in the gene for this regulator protein and does not express any form of the protein. Which statement provides a possible hypothesis to explain the gene X expression data shown in the table below? $$\begin{array} { | c | c | c | }
\hline \text { Bacterial population } & \begin{array} { c }
\text { Regulator protein } \
\text { expression }
\end{array} & \text { Gene } X \text { expression } \
\hline \text { A } & \text { wild-type } & + + + \
\hline \text { B } & \text { none } & 0 \
\hline
\end{array}$$

Question

Two bacterial populations were prepared in a laboratory. Population A expresses the wild-type regulator protein that controls the transcription of gene X. Population B contains a mutation in the gene for this regulator protein and does not express any form of the protein. Which statement provides a possible hypothesis to explain the gene X expression data shown in the table below? $$\begin{array} { | c | c | c | } 
\hline \text { Bacterial population } & \begin{array} { c } 
\text { Regulator protein } \
\text { expression }
\end{array} & \text { Gene } X \text { expression } \
\hline \text { A } & \text { wild-type } & + + + \
\hline \text { B } & \text { none } & 0 \
\hline
\end{array}$$

Quizplus · Accepted Answer

The regulator protein must be an activator because gene X is expressed in population A (where the regulator protein is present) and not expressed in population B (where the regulator protein is absent), indicating that the presence of the regulator protein stimulates gene X transcription.

Two Bacterial Populations Were Prepared in a Laboratory A) the Regulator Protein Is an Activator That Is Required