[02] Thermodynamics in Biology

Question 1

What is the role of thermodynamics in biology?

Answer 1

It helps explain and predict physical and chemical phenomena that occur in biological systems.

Question 2

What does the first law of thermodynamics imply in biological systems?

Answer 2

The total amount of energy in a biological system is conserved; it can be converted from one form to another, but not created or destroyed.

Question 3

What does the second law of thermodynamics imply in biological systems?

Answer 3

Biological processes tend to increase the overall entropy of the universe, though they can create local order.

Question 4

What is Gibbs free energy (ΔG) in biological systems?

Answer 4

The amount of energy capable of doing work during a reaction at constant temperature and pressure.

Question 5

What does a negative ΔG value indicate?

Answer 5

The reaction is spontaneous and releases energy (exergonic).

Question 6

What does a positive ΔG value indicate?

Answer 6

The reaction requires energy to proceed (endergonic).

Question 7

How is ATP related to thermodynamics in biology?

Answer 7

ATP provides energy for endergonic reactions in cells by coupling with them to make the overall ΔG negative.

Question 8

How is entropy related to the functioning of biological systems?

Answer 8

Biological systems increase their order (decrease their own entropy) at the expense of increasing the entropy of their surroundings.

Question 9

What role does thermodynamics play in enzyme function?

Answer 9

Enzymes lower the activation energy of reactions, increasing their rate and making them proceed more efficiently.

Question 10

What is the full form of ATP?

Answer 10

Adenosine Triphosphate.

Question 11

What is the full form of ΔG?

Answer 11

Change in Gibbs Free Energy.

Question 12

What is an example of an endergonic process in biology?

Answer 12

Photosynthesis, which requires energy input to convert carbon dioxide and water into glucose and oxygen.

Question 13

What is an example of an exergonic process in biology?

Answer 13

Cellular respiration, which releases energy by breaking down glucose in the presence of oxygen.

Question 14

What is bioenergetics?

Answer 14

The study of how organisms transform energy.

Question 15

What is the concept of energy coupling in biology?

Answer 15

The use of an exergonic process to drive an endergonic one, typically through the mediation of ATP.

Question 16

What is meant by a “thermodynamically favorable” reaction?

Answer 16

A reaction that results in a decrease in free energy (ΔG<0), and therefore can occur spontaneously.

Question 17

What is meant by a “metabolically favorable” reaction?

Answer 17

A reaction that is favored under the conditions inside a living cell. Not all metabolically favorable reactions are thermodynamically favorable.

Question 18

What is thermodynamic equilibrium in a biological context?

Answer 18

A state in which the rate of the forward reaction equals the rate of the reverse reaction, resulting in no net change in concentrations of reactants or products. Biological systems are rarely at thermodynamic equilibrium.

Question 19

How do cells maintain nonequilibrium states?

Answer 19

Through constant energy input, usually in the form of ATP.

Question 20

How does the second law of thermodynamics apply to the process of life?

Answer 20

While life maintains order and decreases entropy within an organism, it does so by increasing the entropy of the surroundings, resulting in an overall increase in entropy.