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 the change in free energy ($$ \Delta G ) to $$enthalpy ($$ \Delta H $$), entropy ($$ \Delta S $$), and temperature ($$ T $$)?

Accepted Answer

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

Question 7

Which of the following best describes an open system in thermodynamics as it applies to living organisms?

Accepted Answer

A system that exchanges both energy and matter with its surroundings.

Question 8

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

Accepted Answer

Catabolic pathway

Question 9

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

Accepted Answer

Entropy is a measure of the disorder or randomness in a system.

Question 10

A reaction in a cell has $$ \Delta G \u003e 0 . $$What does this imply about the reaction?

Accepted Answer

The reaction is endergonic and requires an input of energy to proceed.

Question 11

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

Accepted Answer

The movement of cilia on the surface of a cell.

Question 12

Why do living organisms never reach equilibrium in their metabolic pathways?

Accepted Answer

Because they are open systems with constant input and output of energy and matter.

Question 13

Which of the following best explains why the breakdown of ATP to ADP and $$ P_i  is $$considered exergonic?

Accepted Answer

It releases free energy that can be used to do cellular work.

Question 14

If a reaction has $$ \Delta H = -20 \; \mathrm{kJ/mol} $$, $$ \Delta S = +0.05 \; \mathrm{kJ/(mol \cdot K)} $$, and $$ T = 300 \; \mathrm{K} $$, what is $$ \Delta G $$ for the reaction?

Accepted Answer

$$ \Delta G = -20 \; \mathrm{kJ/mol} - (300 \; \mathrm{K} 	imes 0.05 \; \mathrm{kJ/(mol \cdot K)}) = -20 - 15 = -35 \; \mathrm{kJ/mol} $$

Question 15

Which of the following scenarios best illustrates the second law of thermodynamics in biological systems?

Accepted Answer

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

Question 16

Which of the following is a spontaneous process in a biological system?

Accepted Answer

A reaction with $$ \Delta G \u003c 0 $$ that increases the entropy of the surroundings.

Question 17

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

Accepted Answer

They catalyze each step, lowering the activation energy required for reactions.

Question 18

A cell is synthesizing a large protein from amino acids. Which type of metabolic pathway is this, and what is the energy implication?

Accepted Answer

Anabolic pathway; energy is consumed.

Question 19

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

Accepted Answer

Magnetic energy stored in a refrigerator magnet.

Question 20

Why do living organisms require a constant input of energy?

Accepted Answer

To maintain order and counteract the increase in entropy.

Metabolism & Energy: Foundations of Biological Energy Transformations

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