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Problem: When the level of glucose in the environment is low, abundant cyclic adenosine monophosphate (CAMP) binds the catabolite activator protein (CAP) to form the CAP-cAMP complex, which binds DNA. When CAP-CAMP binds DNA, the efficiency of RNA polymerase binding is increased at the lac operon promoter, which increases transcription of the structural genes. However, when glucose levels are high, the CAP-CAMP complex does not form and RNA polymerase cannot bind to the promoter efficiently.Is the lac operon inducible or repressible? A. inducibleB. cannot determineC. repressibleWhat type of protein regulates structural-gene expression as a result of glucose level?A. repressorB. activatorC. cannot determineWhat type of overall gene regulation occurs as a response to glucose level?A. positiveB. negativeC. neither

FREE Expert Solution

Inducible Operon: turned on in the presence of the metabolite (ex. lac operon is turned on in the presence of lactose)

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Problem Details
When the level of glucose in the environment is low, abundant cyclic adenosine monophosphate (CAMP) binds the catabolite activator protein (CAP) to form the CAP-cAMP complex, which binds DNA. When CAP-CAMP binds DNA, the efficiency of RNA polymerase binding is increased at the lac operon promoter, which increases transcription of the structural genes. However, when glucose levels are high, the CAP-CAMP complex does not form and RNA polymerase cannot bind to the promoter efficiently.


Is the lac operon inducible or repressible? 

A. inducible
B. cannot determine
C. repressible

What type of protein regulates structural-gene expression as a result of glucose level?

A. repressor
B. activator
C. cannot determine

What type of overall gene regulation occurs as a response to glucose level?

A. positive
B. negative
C. neither

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Our tutors have indicated that to solve this problem you will need to apply the Lac Operon concept. You can view video lessons to learn Lac Operon. Or if you need more Lac Operon practice, you can also practice Lac Operon practice problems.

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Based on our data, we think this problem is relevant for Professor Moscarella's class at UMASS.