81) Phosphofructokinase is an enzyme involved in glycolysis, which is a metabolic pathway involved in ATP production. It can be allosterically regulated by both ATP and ADP. Why is regulating the activity of this enzyme important? Predict what will happen to the rate of reaction when ATP levels in the cell are high, and predict what will happen when the levels of ADP in the cell are high.

Refer to the figure below, and then answer the question that follows.

82) You have a job as an assistant in a morgue. You are startled (almost to death) when a corpse that recently came in suddenly sits up and remains very stiff. This muscle contraction and stiffness in a dead body is known as rigor mortis. Using your knowledge of the ADP/ATP cycle and its role in muscle contraction, explain why rigor mortis occurs.

Refer to the figure below, and then answer the question that follows.

83) The figure above represents:

A) a metabolic pathway.

B) lowering activation energy.

C) competitive inhibition.

D) allosteric regulation.

Refer to the figure below, and then answer the question that follows.

84) The figure above represents allosteric inhibition. Based on the figure, what could be done to allow the enzyme to function again?

A) add more enzyme

B) add more substrate

C) remove some of the product

D) remove some of the substrate