Open Question
For the following lac operon partial diploids, determine whether the synthesis of lacZ mRNA is 'constitutive,' 'inducible,' or 'uninducible,' and indicate whether the partial diploid is or (able or not able to utilize lactose).
12. Gene Regulation in Prokaryotes
Lac Operon
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What happens to the lac operon when the CAP/cAMP complex binds to the CAP binding site?
A
The lac operon genes are transcribed
B
The lac operon genes are suppressed
C
Lactose is synthesized
Verified step by step guidance1
Understand the role of the lac operon: The lac operon is a set of genes in E. coli that are involved in the metabolism of lactose. It includes genes that code for proteins needed to transport and break down lactose into glucose and galactose.
Identify the components involved: The CAP (catabolite activator protein) and cAMP (cyclic AMP) complex is a regulatory protein that binds to the CAP binding site on the DNA near the lac operon.
Recognize the conditions for CAP/cAMP binding: The CAP/cAMP complex forms and binds to the CAP binding site when glucose levels are low, leading to an increase in cAMP levels.
Determine the effect of CAP/cAMP binding: When the CAP/cAMP complex binds to the CAP binding site, it enhances the binding of RNA polymerase to the promoter of the lac operon, thereby facilitating the transcription of the lac operon genes.
Conclude the outcome: As a result of the CAP/cAMP complex binding, the lac operon genes are transcribed, allowing the cell to utilize lactose as an energy source when glucose is not available.
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