Consider the regulation of galactose metabolism through GAL4. Which of the following would result from a mutation that allowed GAL3 to bind to GAL80 in the absence of galactose?
A) Transcription of the genes involved in galactose metabolism would occur both in the presence and in the absence of galactose.
B) GAL80 would be able to bind to GAL4, and transcription of the genes involved in galactose metabolism would be repressed.
C) GAL4 would no longer be able to bind to the DNA; thus, transcription of the genes involved in galactose metabolism would occur.
D) GAL80 would no longer be able to stimulate transcription of the genes involved in galactose metabolism.
E) There would be no change in the regulation of galactose metabolism because GAL3 normally binds to GAL80 to cause a conformation change in GAL80.

Question

Quizplus · Accepted Answer

GAL3 binding to GAL80 in the absence of galactose would prevent GAL80 from inhibiting GAL4, leading to transcription of galactose metabolism genes regardless of galactose presence.

Consider the Regulation of Galactose Metabolism Through GAL4