Final answer:
The statement that AraC protein recruits RNA polymerase when bound to arabinose is true, as AraC facilitates the initiation of transcription of the ara operon under these conditions.
Step-by-step explanation:
In the regulation of the arabinose operon, the AraC protein indeed recruits RNA polymerase when bound to arabinose. Therefore, the statement describing AraC protein recruiting RNA polymerase when bound to arabinose is true. AraC acts as a transcriptional activator in the presence of arabinose. When arabinose is available, it binds to AraC, which then facilitates the binding of RNA polymerase to the promoter of the ara operon, initiating transcription. This regulatory mechanism is similar to the catabolite activator protein (CAP), which also increases transcription in response to certain environmental conditions. In the case of CAP, it requires binding of cyclic AMP (cAMP) to form a complex that can bind to the promoter and stabilize RNA polymerase binding, hence increasing transcription of genes necessary for the metabolism of alternative sugars such as lactose.