Question

You are studying a bacterium that utilizes a sugar called athelose. This sugar can be used as an energy source when necessary. Metabolism of athelose is controlled by the ath operon. The genes of the ath operon code for the enzymes necessary to use athelose as an energy source.

You have found the following: The genes of the ath operon are expressed only when the concentration of athelose in the bacterium is high. When glucose is absent, the bacterium needs to metabolize athelose as an energy source as much as possible. The same catabolite activator protein (CAP) involved with the lac operon interacts with the ath operon. Based on this information, how is the ath operon most likely controlled? Drag the labels onto the diagram to identify the small molecules and the states of the regulatory proteins. Not all labels will be used.

Answer 1

For positive control, (a) will be the inactive activator, (b) will be cAMP, and (c) will be the active activator. In other words, the process won't proceed unless the activator has a molecule bound to it. And the specific molecule necessary, in this case, will be cyclic AMP For negative control, (d) will be the active repressor that is MISSING a molecule, (e) will be athelose, and (f) will be the inactive repressor which HAS a molecule attached to it. In other words, this process will be repressed unless a specific molecule attaches to the active repressor to allow the process to start. The specific molecule necessary, in this case, wl be athelose. Once it binds to the repressor, the repressor will detach and become inactivated, allowing the process to start Us ath operon inactive activator small molecule active activator positive control b CAMIP active repressor small molecule inactive repressor negative control athelose O athelose