Energy and Biosynthesis

Question 1

What do cells derive energy from?

Answer 1

The environment.

Question 2

What role do activated carrier molecules play in cells?

Answer 2

They store and transfer energy in chemical bonds.

Question 3

Why do animals need to eat?

Answer 3

To obtain energy.

Question 4

What is the purpose of metabolism?

Answer 4

To convert food into energy and building blocks for cellular processes.

Question 5

What happens to cells and organisms without energy?

Answer 5

They die.

Question 6

How do chemical reactions occur?

Answer 6

Through the interaction of molecules.

Question 7

What is the first law of thermodynamics?

Answer 7

Total energy in the universe is constant.

Question 8

What is the second law of thermodynamics?

Answer 8

Free energy in the universe declines over time, leading to increased disorder (entropy).

Question 9

What is free energy (G)?

Answer 9

Energy that can do work at constant temperature and pressure.

Question 10

What does the Gibbs Free Energy equation represent?

Answer 10

ΔH = ΔG + TΔS.

Question 11

What does a negative ΔG indicate?

Answer 11

A spontaneous reaction.

Question 12

What is an example of a spontaneous reaction?

Answer 12

ATP → ADP + P releases free energy.

Question 13

What allows unfavorable reactions to occur?

Answer 13

Coupling to favorable reactions.

Question 14

What are reaction chains?

Answer 14

Biological reactions occurring in sequences where each step contributes to the overall metabolic goal.

Question 15

What is activation energy?

Answer 15

The energy required to start a reaction.

Question 16

How do enzymes influence activation energy?

Answer 16

They lower activation energy and speed up reactions.

Question 17

Define oxidation in terms of electrons.

Answer 17

Loss of electrons.

Question 18

Define reduction in terms of electrons.

Answer 18

Gain of electrons.

Question 19

What is the most stable form of carbon?

Answer 19

CO₂.

Question 20

What is the most stable form of hydrogen?

Answer 20

H₂O.

Question 21

What is the glucose oxidation reaction?

Answer 21

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP).

Question 22

What is stepwise oxidation?

Answer 22

Gradual electron transfer that releases energy in controlled steps.

Question 23

What is hydrogenation?

Answer 23

Addition of hydrogen to an organic molecule (reduction).

Question 24

What is the purpose of activated carrier molecules?

Answer 24

Store and transfer energy in chemical bonds.

Question 25

What is the most abundant energy carrier?

Answer 25

ATP (Adenosine Triphosphate).

Question 26

What does the hydrolysis of ATP release?

Answer 26

~ -13 kcal/mol energy.

Question 27

How much ATP is recycled per day in a human?

Answer 27

~ 50 kg.

Question 28

What do NADH and NADPH carry?

Answer 28

High-energy electrons from oxidation reactions.

Question 29

What is the oxidized form of NADH?

Answer 29

NAD⁺.

Question 30

What is the reduced form of NAD?

Answer 30

NADH.

Question 31

What does acetyl-CoA transfer?

Answer 31

Acetyl groups in metabolism.

Question 32

What is ATP hydrolysis?

Answer 32

ATP in water undergoes hydrolysis, releasing free energy.

Question 33

What is required for ATP regeneration?

Answer 33

Input of energy (e.g., from food oxidation).

Question 34

What do cells follow to maintain energy balance?

Answer 34

The laws of thermodynamics.

Question 35

What determines reaction spontaneity?

Answer 35

Free energy (ΔG).

Question 36

What role do oxidation-reduction reactions play?

Answer 36

They are critical for energy transfer.

Question 37

How do enzymes facilitate biological reactions?

Answer 37

By lowering activation energy.

Question 38

Fill in the blank: The oxidation of glucose can be summarized as C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + _______.

Answer 38

Energy (ATP).