A bacterial growth curve is presented below. The curve represents ________ growth, which is caused by the ________.
A) binary; addition of more growth media after the fulture reaches stationary phase
B) diauxic; addition of more growth media after the fulture reaches stationary phase
C) binary; addition of a needed vitamin after it runs out
D) diauxic; addition of a needed vitamin after it runs out
E) diauxic; growth on two carbon sources resulting in a lag after the preferred substrate is depleted; new genes are then induced and growth resumes

Question

A bacterial growth curve is presented below. The curve represents ________ growth, which is caused by the ________. 
A) binary; addition of more growth media after the fulture reaches stationary phase 
B) diauxic; addition of more growth media after the fulture reaches stationary phase 
C) binary; addition of a needed vitamin after it runs out 
D) diauxic; addition of a needed vitamin after it runs out 
E) diauxic; growth on two carbon sources resulting in a lag after the preferred substrate is depleted; new genes are then induced and growth resumes

Quizplus · Accepted Answer

The growth curve shown has two distinct phases, indicating that the bacteria are growing on two different carbon sources. This is known as diauxic growth. There is a lag phase after the preferred substrate is depleted, followed by induction of new genes and resumption of growth. Therefore, the best choice is E.

A Bacterial Growth Curve Is Presented Below