Genes Whose Expression is Turned Off in Response to a Substance

Question

Genes whose expression is turned off in response to a substance in the environment are known as
A) inducible genes.
B) repressible genes.
C) constitutive genes.
D) inducible genes and repressible genes.
E) All of these are correct.

Accepted Answer

Repressible genes are those that are normally turned on but can be turned off in response to a substance in the environment. Inducible genes are those that are normally turned off but can be turned on in response to a substance in the environment. Constitutive genes are those that are always turned on and are essential for basic cellular functions. Hence, only option B is correct.