Final answer:
In the metabolic pathway discussed, the end product D acting as a noncompetitive inhibitor of Enzyme 1 exemplifies feedback inhibition. This results in the decreased conversion of substrate A to product D, and shows that Enzyme 1 possesses both an active site and a regulatory site. Option D is correct.
Step-by-step explanation:
When considering the metabolic pathway described, where the end product D inhibits Enzyme 1 by binding to a separate site from the active site, this scenario exemplifies a case of noncompetitive inhibition, also known as allosteric inhibition.
The presence of product D at a regulatory site of Enzyme 1 induces a conformational change that impairs the enzyme's ability to bind substrate A at the active site. This form of regulation is referred to as feedback inhibition, whereby the accumulation of the end product regulates the pathway's activity.
The inhibitory effect of product D on Enzyme 1 results in a decrease in the conversion of substrate A into the subsequent products, which means there will eventually be less substrate converted to the end product D.
This regulatory mechanism prevents the wasteful production of substance E when it is not needed by the cell, highlighting the importance of feedback control in metabolic pathways.
Given that Enzyme 1 has both an active site for substrate binding and a regulatory site for feedback inhibition by the end product, it can be deduced that all of the provided choices are correct.