OBJECTIVE LIFE SCIENCE
MOLECULAR BIOLOGY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
lactose sensor
|
|
|
sense glucose through hunger signal, cAMP
|
|
|
active the transcription when the glucose is high
|
|
|
stop the transcription of the operon when the glucose is low
|
Detailed explanation-1: -Catabolite activator protein (CAP) acts as a glucose sensor. It activates transcription of the operon, but only when glucose levels are low. CAP senses glucose indirectly, through the “hunger signal” molecule cAMP.
Detailed explanation-2: -Glucose and related sugars repress the transcription of genes encoding enzymes required for the utilization of alternative carbon sources; some of these genes are also repressed by other sugars such as galactose, and the process is known as catabolite repression.
Detailed explanation-3: -Catabolite Activator Protein (CAP): An Activator Regulator Just as the trp operon is negatively regulated by tryptophan molecules, there are proteins that bind to the operator sequences that act as a positive regulator to turn genes on and activate them. For example, when glucose is scarce, E.