Cell differentiation occurs when various genes are expressed to a different extent in different cells. What does it mean for a gene to be "turned off," or not expressed?

A. Transcription into RNA does not occur for that gene.

B. That gene is removed from the cell's DNA.

C. The RNA for that gene is not translated into protein.

D. The proteins sequenced by that gene are broken down inside the cell.

C.

Explanation:

When it is said that a gene is "turned off" this usually means that this particular gene is no longer making the directions that need to be followed in order to make proteins. Therefore the proteins that are needed for a specific job, such as tolerating lactose, are not being produced. So the answer in this question would be that the RNA for that gene is not translated into protein.