Final answer:
The statements in the question are related to enzyme regulation. The first statement about feedback inhibition is true; the second statement about allosteric binding also holds true, indicating enzyme activity can be reduced. The third statement is false because protein phosphorylation can both increase and decrease enzyme activity, not exclusively increase it.
Step-by-step explanation:
The question pertains to the regulation of enzyme activity, particularly through mechanisms like allosteric inhibition, feedback inhibition, and protein phosphorylation. Here are the statements evaluated:
- Feedback inhibition is defined as a mechanism which down-regulates enzyme activity through the accumulation of a product earlier in the pathway. This statement is true. The end product of a pathway can act as a noncompetitive inhibitor to an enzyme early in the pathway, thus preventing excess production.
- If an enzyme's allosteric binding site is occupied, the enzyme may adopt an alternative conformation that is not optimal for catalysis. This statement is true. Allosteric inhibitors cause a conformational change in the enzyme that can reduce its activity, while allosteric activators can increase enzyme activity.
- Protein phosphorylation is another way to alter the conformation of an enzyme and serves exclusively as a mechanism to increase enzyme activity. This statement is false. Protein phosphorylation can both increase or decrease enzyme activity depending on the specific enzyme and the site of phosphorylation.