Which is True of Catabolite Repression

Question

Which is true of catabolite repression?
A)It results in diauxic growth.
B)It results in decreased growth rates.
C)It results in increased growth rates.
D)It occurs because of the toxicity of certain chemicals.
E)It only occurs when lactose is present.

Accepted Answer

Catabolite repression occurs when a preferred carbon source (such as glucose) is present, causing repression of the genes necessary for utilizing other carbon sources. This leads to a temporary halt in growth until the glucose is fully consumed, at which point the cells switch to utilizing the alternative carbon source and resume growth. This phenomenon is called diauxic growth.