Thermodynamics (1)

Question 1

Anabolism

Answer 1

Biochemical reactions that make larger molecules from smaller subunits (ex. dehydration synthesis reactions).

Question 2

Catabolism

Answer 2

Biochemical reactions that break-down large molecules to make smaller subunits (ex. hydrolysis reactions).

Question 3

Metabolism

Answer 3

All biochemical reactions that take place within an organism.

Question 4

Energy

Answer 4

The ability to do work (move an object) or heat an object, measured in Joules (J) or kilocalories (kcal).

Question 5

Kinetic Energy

Answer 5

The energy of an object is due to its motion.

Question 6

Potential Energy.

Answer 6

The energy that is stored in an object due to its relative position, charge, or stress

Question 7

First Law of Thermodynamics (Law of Conservation of Energy)

Answer 7

Energy cannot be created nor destroyed; only converted from one form to another. (Energy Into System Energy Out of System)

Question 8

Enthalpy (H)

Answer 8

The total energy (sometimes called heat) content of a substance.

Question 9

ΔH

Answer 9

The change in the amount of heat in a reaction system as reactants turn into products.

Question 10

Exothermic Reaction

Answer 10

A chemical reaction that overall releases energy. ΔH is a negative value

Question 11

Endothermic Reaction

Answer 11

A chemical reaction that overall absorbs energy. ΔH is a positive value

Question 12

Entropy (S)

Answer 12

The amount of disorder/randomness in a system.

Question 13

ΔS

Answer 13

The change in entropy of a system as reactants turn into products.

Question 14

Second Law of Thermodynamics

Answer 14

Reactions that increase the entropy (ΔS > 0) of the universe are favoured.

Question 15

Spontaneous Reaction

Answer 15

A reaction that will occur on its own without an external source of energy.

Question 16

What is Gibbs Free Energy (G) and how is ΔG calculated?

Answer 16

Gibbs Free Energy (G) is the useful (free) energy within a system. The change in free energy (ΔG) is calculated as:

ΔG =ΔH−T ΔS

where:

ΔG = free energy change (J)
ΔH = enthalpy change (J)
T =temperature (K)
ΔS = entropy change (J/K)

Question 17

Q: What do the values of
ΔG indicate about a reaction?

Answer 17

ΔG<0: Reaction is exergonic (spontaneous).

ΔG>0: Reaction is endergonic (not spontaneous) and requires an external energy source.

ΔG=0: Reaction is at equilibrium.

Question 18

what does this picture represent:

Answer 18

endergonic reaction requires an external energy source to complete. Overall, it absorbs energy.

Question 19

what does the picture represent:

Answer 19

exergonic reaction does not require an external energy source to complete. Overall, it releases energy.

Question 20

Q: How does the ΔG of cellular respiration relate to energy production?

Answer 20

Cellular respiration has
kJ/mol
ΔG=−2870kJ/mol, making it a spontaneous process that releases energy from glucose. This energy is used to synthesize ATP, a more readily available energy source for cells.

Question 21

How does the ΔG of photosynthesis relate to energy absorption?

Answer 21

Photosynthesis has
ΔG=2870kJ/mol, making it a non-spontaneous (endergonic) process. It absorbs energy from sunlight to synthesize glucose.

Question 22

What is the ATP-ADP cycle?

Answer 22

The ATP-ADP cycle is how cells get and use energy. ATP loses a phosphate to become ADP, releasing energy for the cell to use. ADP is then turned back into ATP using energy from food.

Question 23

What happens when ATP is used to provide energy?

Answer 23

When ATP provides energy, it is coupled with another reaction that uses the released energy to perform work or drive the process forward.