Question 1

Which of the following best describes the Second Law of Thermodynamics as it applies to biological systems?

Accepted Answer

Every energy transfer or transformation increases the entropy (disorder) of the universe.

Question 2

A cell breaks down glucose in the presence of oxygen to produce carbon dioxide and water, releasing energy. This process is an example of which type of metabolic pathway?

Accepted Answer

Catabolic pathway

Question 3

Which of the following statements about ATP is correct?

Accepted Answer

ATP hydrolysis releases energy that can be used to drive endergonic reactions.

Question 4

A reaction has a negative free energy change ($$\Delta G \u003c 0). $$What does this indicate about the reaction?

Accepted Answer

The reaction is spontaneous and can perform work.

Question 5

Which of the following is an example of kinetic energy in a biological system?

Accepted Answer

A muscle contracting to move a limb.

Question 6

Which statement best explains why enzymes are necessary for metabolic reactions in living organisms?

Accepted Answer

Enzymes lower the activation energy barrier, allowing reactions to occur more rapidly at body temperature.

Question 7

A protein's function is most directly determined by which of the following?

Accepted Answer

Its three-dimensional shape, which is determined by its amino acid sequence.

Question 8

Which of the following best describes the role of feedback inhibition in metabolic pathways?

Accepted Answer

It prevents the overaccumulation of the end product by inhibiting an early enzyme in the pathway.

Question 9

Which of the following scenarios illustrates the First Law of Thermodynamics?

Accepted Answer

A bear eats fish, converting the chemical energy in the fish to kinetic energy for running.

Question 10

If an enzyme is exposed to a temperature much higher than its optimal range, what is the most likely outcome?

Accepted Answer

The enzyme will denature, losing its specific shape and function.

Question 11

Which of the following is true about chemical equilibrium in a reaction?

Accepted Answer

The forward and reverse reactions occur at the same rate.

Question 12

A scientist adds a noncompetitive inhibitor to an enzyme-catalyzed reaction. What is the most likely effect?

Accepted Answer

The inhibitor binds to a site other than the active site, changing the enzyme's shape and reducing its activity.

Question 13

Which of the following best describes energy coupling in cells?

Accepted Answer

Using the energy released from exergonic reactions to drive endergonic reactions.

Question 14

Which of the following is an example of potential energy in a biological context?

Accepted Answer

A molecule of glucose before it is metabolized.

Question 15

What is the main reason why some energy is always lost as heat during energy transformations?

Accepted Answer

The Second Law of Thermodynamics states that every energy transfer increases entropy, and some energy is always lost as heat.

Question 16

Which of the following best explains why ATP is considered a renewable resource in cells?

Accepted Answer

ATP can be regenerated from ADP and inorganic phosphate through cellular respiration.

Question 17

A reaction has a positive free energy change ($$\Delta G \u003e 0). $$Which of the following is true?

Accepted Answer

The reaction is endergonic and requires energy input.

Question 18

Which of the following is a correct statement about enzyme specificity?

Accepted Answer

Enzymes are specific to their substrates due to the unique shape of their active site.

Question 19

Which of the following best describes the induced fit model of enzyme function?

Accepted Answer

The enzyme changes shape slightly to fit the substrate more snugly upon binding.

Question 20

Which of the following is an example of allosteric regulation of an enzyme?

Accepted Answer

A molecule binds to a site other than the active site, stabilizing the enzyme's active or inactive form.

Energy, Metabolism, and Enzymes in Biological Systems

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