The lac operon
A. is an example of negative control.
B. is affected by catabolite repression.
C. produces lactose.
D. is an example of a regulon.
E. is an example of negative control AND is affected by catabolite repression.
Negative control means a regulator molecule is
A. bound and transcription starts.
B. removed and transcription is inhibited.
C. bound and transcription is inhibited.
D. removed and transcription starts.
E. bound and transcription is inhibited AND removed and transcription starts.
Activators
A. are involved in negative control.
B. are involved in positive control.
C. always bind to the promoter.
D. are allosteric proteins.
E. are involved in positive control AND are allosteric proteins.
Glucose
A. is preferentially used over lactose in E. coli as a result of catabolite repression.
B. levels are directly sensed via catabolite repression.
C. levels are the inverse of cAMP levels.
D. levels directly affect the production of lactose dehydrogenase.
E.
is preferentially used over lactose in E. coli as a result of catabolite repression AND glucose levels are the inverse of cAMP levels.
Repressors
A. are involved in negative control.
B. are involved in positive control.
C. always bind to the promoter.
D. bind or do not bind to the operator depending on their shape (conformation).
E. are involved in negative control AND bind or do not bind to the operator depending on their shape (conformation).
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