Which of the Following is an Example of a Cis-Acting

Question

Which of the following is an example of a cis-acting element?
A)$\beta$-galactosidase
B)operator site
C)lacI repressor protein
D)lactose
E)permease

Accepted Answer

A cis-acting element is a DNA sequence that regulates the expression of a nearby gene. The operator site is a cis-acting element because it is a specific sequence of DNA located adjacent to the gene it controls, and its presence or absence affects gene expression. The other options are either proteins or molecules that interact with cis-acting elements but are not themselves cis-acting elements.