Suppose that a repressor regulated the expression of the galA gene. Which of the parenthesis would be correct?
(((supposing hypothetical bacterium gene:
"galA" – encodes an enzyme that is required for cells to digest the sugar galactose/and/
"argB" – encodes an enzyme that is required for cells to produce the amino acid arginine))))
Question:
The repressor for the galA gene (would/would not) bind to DNA in the (presence/absence) of galactose.
To determine whether the repressor for the galA gene would bind to DNA in the presence or absence of galactose, we can use our knowledge of gene regulation.
The galA gene encodes an enzyme required for cells to digest the sugar galactose. In the absence of galactose, the bacterium would need to conserve resources and not produce the enzyme unnecessarily.
In gene regulation, a repressor is a protein that binds to the DNA near the promoter region of a gene, preventing the transcription of that gene. When the repressor binds to the DNA, it forms a complex that blocks the binding of RNA polymerase, which is required for gene expression.
Based on this information, we can deduce that the repressor for the galA gene would bind to DNA in the presence of galactose. When galactose is present, it signals that the bacterium needs to digest the sugar, and therefore the repressor is released from its binding site on the DNA, allowing RNA polymerase to bind and transcribe the galA gene.
So, the correct answer would be: The repressor for the galA gene would bind to DNA in the absence of galactose.