If glucose is available in the environment of E. coli, the cell responds with very low concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of the following would you expect would then be a measurable effect?
a. decreased concentration of the lac enzymes.
b. increased concentration of the trp enzymes.
c. decreased binding of the RNA polymerase to sugar metabolism-related promoters.
d. decreased concentration of alternative sugars in the cell.
e. increased concentrations of sugars such as arabinose in the cell.

E. Increased concentrations of sugars such as arabinose in the cell.

Explanation:

Here, after different tests and many different combinations of carbon and nitrogen sources, on a reasonable variety of laboratory and naturally occurring strains, it was found that under some poor nitrogen sources such as certain amino acids, glucose becomes one of the worst carbon sources, supporting lower growth rate than other sugars. This is due to very low cAMP levels that are suboptimal for growth: growth can be improved by experimentally increasing cAMP levels, by either adding external cAMP, genetically manipulating cAMP levels, or inhibiting glucose uptake.

Increased concentrations of sugars such as arabinose in the cell would be a measurable effect. The correct option is E.

Explanation:

Escherichia coli is a type of bacteria that responds to concentration of glucose in its surroundings or environment which is regulated by Cyclic Adenosine monophosphate (cAMP). When glucose concentration is high, the cAMP concentration decreases. Also cAMP increases with decreases glucose concentration. In this state( decreased glucose in the surrounding),E.coli makes use of arabinose which serves as an alternative source of carbon for energy to the bacteria. This secondary source of carbon( arabinose) increases when the primary source is exhausted. Therefore. Increased concentrations of sugars such as arabinose in the cell would be a measurable effect. I hope this helps, thanks.

b would be the right answer