When glucose is high, cAMP is low; CAP does not bind the lac operator, and RNA polymerase does not bind the lac promoter. CAP is only active when glucose levels are low, which means the cAMP levels are high, and therefore the lac operon can only be transcribed at high rate when glucose is absent. The importance of this is that the bacteria only turns on the lac operon and start using lactose only after they have used up all the preferred energy source which is glucose.
An example i can think of is...
the amount of salt present in human cells cytoplasm suggests we evolved from species in the sea
<span>a. chemicals produced by neurons that function as hormones—neurohormones
b. chemicals that act locally on nearby cells—paracrine factors
c. chemicals secreted by presynaptic terminal—neurotransmiters
d. influences same cell type from which it is secreted—autocrine agent
e. chemical secreted into the blood by specialized cells; travels some distance to target tissues—endocrine hormones</span>
Answer: False
Explanation: You're supposed to have numerically more smaller units than bigger units, since a lot of these smaller units are combined to create a single larger unit.
Organ systems is the answer