Some genes are important enough to be called "molecular switch" or "master" genes. What is the purpose of these genes? A. They control when other genes are expressed
B. They determine the organization of the genome
C. They regulate cell metabolism
D. They modulate the rate of translation

Genes called "molecular switch" or master genes have the purpose of control when other genes are expressed (option A).

Explanation:

Master gene is so named because it has the function of controlling the behavior of other genes, organizing their functions and regulating when they can be expressed.

The name of molecular switch is synonymous with the master gene, since its activation determines the genetic regulation necessary to establish cell differentiation and even the determination of the sex of some species.

The other options are not correct because:

    B. Master genes do not determine the organization of the genome .

    C. Regulation of cell metabolism depends of substances as hormones and enzymes.

    D. The rate of translation does not depend on the activity of master genes.