Question 1

Which of the following best describes how enzymes increase the rate of chemical reactions?

Accepted Answer

By lowering the activation energy barrier

Question 2

A metabolic pathway consists of several enzymes working in sequence. If Enzyme 3 is blocked by an allosteric inhibitor, what will happen to the concentration of its substrate?

Accepted Answer

It will increase due to accumulation before the blocked step

Question 3

Which statement about enzymes is FALSE?

Accepted Answer

Enzymes are always part of the final product

Question 4

The hydrolysis of ATP to ADP is described by the following equation: $ \mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy} $. What is the standard free energy change ($ \Delta G $) for this reaction?

Accepted Answer

$ \Delta G = -7.3 \ \mathrm{kcal/mol} $

Question 5

Which of the following is an example of coupling an exergonic reaction to drive an endergonic reaction in cells?

Accepted Answer

Using the energy released from ATP hydrolysis to power muscle contraction

Question 6

Which metabolic pathway is primarily responsible for breaking down molecules to release energy?

Accepted Answer

Catabolic pathway

Question 7

If a cell needs to synthesize new molecules, which type of metabolic pathway will be most active?

Accepted Answer

Anabolic pathway

Question 8

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

ATP hydrolysis releases energy that can be coupled to endergonic reactions

Question 9

A scientist blocks the active site of an enzyme with a competitive inhibitor. What is the most likely outcome?

Accepted Answer

The substrate will outcompete the inhibitor if its concentration is increased

Question 10

Which of the following is TRUE regarding feedback inhibition in metabolic pathways?

Accepted Answer

The final product of the pathway inhibits the first enzyme in the pathway

Question 11

Consider the following scenario: The cell requires 15 units of energy for an endergonic reaction. If ATP hydrolysis releases 7.3 units of energy per molecule, how many ATP molecules must be hydrolyzed to drive the reaction?

Accepted Answer

2 ATP molecules

Question 12

Which of the following statements about metabolic pathways is correct?

Accepted Answer

The product of one reaction often serves as the substrate for the next

Question 13

Which of the following best describes an allosteric inhibitor?

Accepted Answer

It binds to a site other than the active site and changes enzyme conformation

Question 14

If the concentration of an allosteric inhibitor increases, what is the expected effect on the metabolic pathway it regulates?

Accepted Answer

The pathway will slow down due to decreased enzyme activity

Question 15

Which of the following is a correct statement about the role of enzymes in metabolism?

Accepted Answer

Enzymes lower the activation energy required for metabolic reactions

Question 16

Which of the following equations correctly represents the coupling of ATP hydrolysis to an endergonic reaction?

Accepted Answer

$ 	ext{Endergonic Reaction} + 	ext{ATP} ightarrow 	ext{Product} + 	ext{ADP} + 	ext{P}_i $

Question 17

Which of the following is NOT a feature of enzymes?

Accepted Answer

They are consumed in the reaction

Question 18

A patient is given a drug that acts as an allosteric inhibitor for a key enzyme in glucose metabolism. What is the most likely effect?

Accepted Answer

Glucose breakdown will decrease

Question 19

Which of the following best explains why metabolic pathways are often regulated by feedback inhibition?

Accepted Answer

To prevent the accumulation of excess products and conserve resources

Question 20

Which of the following is a correct description of the difference between catabolic and anabolic pathways?

Accepted Answer

Catabolic pathways break down molecules to release energy, while anabolic pathways build complex molecules

Enzymes, Energy, and Metabolism: Study Notes

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