Final answer:
Cells turn orange when fan (paternally-imprinted gene) is expressed, as the production of fan protein is responsible for the orange coloration.
So, the correct answer to the question is C) Cells turn orange when fan is expressed.
Step-by-step explanation:
The regulation of gene expression is a fundamental aspect of biology that allows cells to function efficiently and specialize into different cell types. In the context of your question regarding the paternally-imprinted gene fan, the correct answer is that cells turn orange when fan is expressed because the production of fan protein determines the orange coloration of the cells.
Therefore, if fan is not being expressed, the cells would not produce the fan protein and would not turn orange; instead, they would appear blue. So, the correct statement about these cells is: c) Cells turn orange when fan is expressed.
It is important to understand that the phenotype of a cell—which includes its observable characteristics such as color—is determined by the proteins that are expressed.
Since the fan gene is responsible for the production of a protein that turns cells orange, only when fan is active (i.e., being expressed) do the cells exhibit this orange phenotype. Conversely, when the gene is not expressed, the resultant phenotype is different—in this case, blue.
So, the correct answer is C) Cells turn orange when fan is expressed.