Question 1

Which of the following best describes metabolism in living organisms?

Accepted Answer

The sum of all chemical reactions occurring within a living organism.

Question 2

Which statement correctly distinguishes between catabolic and anabolic pathways?

Accepted Answer

Catabolic pathways break down complex molecules and release energy, while anabolic pathways build complex molecules and consume energy.

Question 3

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

Accepted Answer

The energy stored in the chemical bonds of glucose.

Question 4

According to the first law of thermodynamics, which of the following is true?

Accepted Answer

Energy can be transformed from one form to another but cannot be created or destroyed.

Question 5

A chemical reaction has a $$ \Delta G  ($$change in free energy) of $$ -15 \; \mathrm{kJ/mol} . $$What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and will occur spontaneously.

Question 6

Which equation correctly relates free energy change to enthalpy, entropy, and temperature?

Accepted Answer

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

Question 7

Which of the following best explains why living organisms do not reach equilibrium in their metabolic pathways?

Accepted Answer

They are open systems with a constant flow of materials and energy.

Question 8

During cellular respiration, glucose is broken down and energy is released. Which type of metabolic pathway and energy transformation does this represent?

Accepted Answer

Catabolic pathway; chemical energy to kinetic/thermal energy

Question 9

Which of the following statements about entropy ($$ S ) is $$correct?

Accepted Answer

Entropy is a measure of disorder, and spontaneous processes increase the entropy of the universe.

Question 10

A reaction has $$ \Delta H = +10 \; \mathrm{kJ/mol} $$, $$ \Delta S = +0.05 \; \mathrm{kJ/(mol \cdot K)} $$, and occurs at $$ T = 300 \; \mathrm{K} . $$Calculate $$ \Delta G $$ and determine if the reaction is spontaneous.

Accepted Answer

$$ \Delta G = -5 \; \mathrm{kJ/mol} $$, spontaneous

Question 11

Which of the following best describes an endergonic reaction?

Accepted Answer

A reaction that absorbs energy and has a positive $$ \Delta G .$$

Question 12

In a hydroelectric dam, water at a high elevation has potential energy. When the water flows down and turns turbines, what type of energy transformation occurs?

Accepted Answer

Potential energy is converted to kinetic energy.

Question 13

Which of the following is a real-life example of the second law of thermodynamics in biological systems?

Accepted Answer

During metabolism, some energy is lost as heat, increasing the entropy of the surroundings.

Question 14

Which of the following best defines bioenergetics?

Accepted Answer

The study of how energy flows through and is used by living organisms.

Question 15

A metabolic pathway involves several steps, each catalyzed by a different enzyme. What is the main advantage of this multi-step process?

Accepted Answer

It allows for regulation and control at each step, increasing efficiency and flexibility.

Question 16

Which of the following is NOT a form of energy relevant to biological systems?

Accepted Answer

Magnetic energy

Question 17

If a reaction in a cell is nonspontaneous, what must be true about its $$ \Delta G $$ and energy requirements?

Accepted Answer

$$ \Delta G  is $$positive and energy must be supplied for the reaction to proceed.

Question 18

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

Accepted Answer

To maintain order and perform work, counteracting the tendency toward increased entropy.

Question 19

Which of the following is an example of an anabolic pathway?

Accepted Answer

Synthesis of proteins from amino acids.

Question 20

A cell is performing a reaction with $$ \Delta H = -20 \; \mathrm{kJ/mol} $$ and $$ \Delta S = -0.04 \; \mathrm{kJ/(mol \cdot K)}  at$$ $$ T = 310 \; \mathrm{K} . $$Calculate $$ \Delta G $$ and determine if the reaction is spontaneous.

Accepted Answer

$$ \Delta G = -7.6 \; \mathrm{kJ/mol} $$, spontaneous

Metabolism & Energy: Foundations of Bioenergetics

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