6. When the end product of a pathway inhibits catalysis of the first step of that pathway, this phenomenon is called A. reversible covalent modification. B. feedback inhibition. C. metabolic channeling. D. non-competitive inhibition.

B) Feedback inhibition

Explanation:

Feedback inhibition is a situation in which the end product of a reaction controls the action of the enzyme that helped produce it. In this process the end products formed at the end of a sequence of reactions participate in inhibiting the activity of the enzymes that helped synthesis the end product. Some examples of products that are used in feedback inhibition are CTP, citrate and Isoleucine. While negative feedback is used in the context of inhibition, negative feedback may also be used for promoting a certain process.

Therefore, when the end product of a pathway inhibits catalysis of the first step of that pathway, this phenomenon is called Feedback inhibition.

d. cellulose and starch