Question 1

Which of the following best explains why a large, complex molecule like a protein contains more potential energy than a small molecule such as glucose?

Accepted Answer

Complex molecules have more chemical bonds, which store more energy that can be released during catabolic reactions.

Question 2

Which statement best describes why most energy transformations in living organisms are not 100% efficient?

Accepted Answer

Some energy is always lost as heat due to the second law of thermodynamics.

Question 3

A cell uses ATP to drive an endergonic reaction. Which equation correctly represents the coupling of ATP hydrolysis to this reaction?

Accepted Answer

$$ \Delta G_{total} = \Delta G_{reaction} + \Delta G_{ATP\ hydrolysis} $$

Question 4

Which of the following would most likely increase the rate of an enzyme-catalyzed reaction?

Accepted Answer

Increasing the temperature to just below the enzyme's denaturation point.

Question 5

A scientist observes that a reaction in a test tube proceeds faster when the reactants are mixed. What is the most likely explanation?

Accepted Answer

Mixing increases the frequency of collisions between reactant molecules, increasing reaction rate.

Question 6

Which of the following is an example of an exergonic reaction in biological systems?

Accepted Answer

Hydrolysis of ATP to ADP and inorganic phosphate.

Question 7

If a plant is placed in a sealed chamber with only green light, what is the most likely outcome?

Accepted Answer

The plant will photosynthesize poorly because chlorophyll reflects green light.

Question 8

Which of the following best describes the role of enzymes in metabolic pathways?

Accepted Answer

Enzymes lower the activation energy, allowing reactions to occur at cellular temperatures.

Question 9

A person is unable to produce sufficient insulin. Which metabolic process is most directly affected?

Accepted Answer

Regulation of blood glucose levels.

Question 10

Which of the following statements about entropy is correct?

Accepted Answer

Entropy tends to increase in isolated systems, leading to greater disorder.

Question 11

Which equation correctly represents the change in free energy for a chemical reaction?

Accepted Answer

$$ \Delta G = \Delta H - T \Delta S $$

Question 12

A cell is placed in a hypertonic solution. What will most likely happen to the cell?

Accepted Answer

Water will leave the cell, causing it to shrink.

Question 13

Which of the following is a real-world example of an anabolic pathway?

Accepted Answer

Synthesis of proteins from amino acids during muscle growth.

Question 14

A patient is given a drug that blocks the active site of an enzyme. What type of inhibition is this?

Accepted Answer

Competitive inhibition.

Question 15

Which of the following best explains why living organisms require a constant input of energy?

Accepted Answer

To maintain order and counteract the tendency toward entropy.

Question 16

Which process is most directly responsible for the release of oxygen into the atmosphere by plants?

Accepted Answer

Photolysis of water during photosynthesis.

Question 17

A scientist wants to increase the yield of a product in a metabolic pathway. Which strategy would be most effective?

Accepted Answer

Increase the concentration of substrate and ensure optimal enzyme conditions.

Question 18

Which of the following is true about the energy changes in the conversion of glucose to carbon dioxide and water?

Accepted Answer

It is an exergonic process that releases energy for cellular work.

Question 19

Which of the following would most likely occur if the entropy of a system decreases?

Accepted Answer

The system becomes more ordered and less spontaneous.

Question 20

A cell is observed to have a high concentration of product and a low concentration of substrate. What is the most likely effect on the metabolic pathway?

Accepted Answer

Feedback inhibition will slow or stop the pathway.

Ch. 5: The Working Cell – Essay Questions Study Guide

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