4 - Cellular Respiration

Question 1

What are the 3 steps of Aerobic Cellular Respiration?

Answer 1

1. Glycolysis
2. Citric Acid Cycle
3. Oxidative Phosphorylation

Question 2

Where does Glycolysis occur?

Answer 2

Cytosol

Question 3

Where does the Citric Acid Cycle occur?

Answer 3

Mitochondrial Matrix

Question 4

Where does Oxidative Phosphorylation occur?

Answer 4

Inner Membrane

Question 5

Where is mitochondrial DNA inherited from?

Answer 5

Maternally inherited

Question 6

What structure increases the surface area for ATP production in mitochondria?

Answer 6

Cristae

Question 7

What is the net reaction of cellular respiration?

Answer 7

Glucose + O₂ → 6CO₂ + 6H₂O + ATP

Question 8

What is the key regulatory enzyme of glycolysis?

Answer 8

Phosphofructokinase (PFK)

Question 9

What are the two phases of glycolysis?

Answer 9

Energy Investment and Energy Payoff

Question 10

What is the net yield of glycolysis?

Answer 10

2 ATP, 2 NADH, 2 pyruvate per glucose.

Question 11

What happens to pyruvate if oxygen is absent?

Answer 11

It undergoes fermentation

Question 12

What are the total outputs of the Citric Acid Cycle per glucose molecule?

Answer 12

6 NADH, 2 FADH₂, 2 ATP, and 4 CO₂.

Question 13

What is the first step of the Citric Acid Cycle?

Answer 13

Acetyl CoA combines with oxaloacetate to form citrate.

Question 14

What is the final electron acceptor in the ETC? What does it form?

Answer 14

Oxygen, forming water.

Question 15

How does the ETC generate ATP?

Answer 15

By creating a proton gradient that powers ATP synthase.

Question 16

How much ATP is produced by the ETC per glucose molecule?

Answer 16

~34 ATP

Question 17

What is the main purpose of fermentation?

Answer 17

To regenerate NAD⁺ for glycolysis.

Question 18

What are the two types of fermentation and their outputs?

Answer 18

Alcohol fermentation (ethanol + CO₂) and lactic acid fermentation (lactate).

Question 19

When does lactic acid fermentation occur in humans?

Answer 19

During intense exercise when oxygen is low.

Question 20

What is the preferred energy source for cellular respiration?

Answer 20

Glucose

Question 21

What is the difference between catabolic and anabolic reactions?

Answer 21

Catabolic: break molecules for energy; Anabolic: build molecules, consuming energy.

Question 22

The process of storing excess glucose as glycogen

Answer 22

Glycogenesis

Question 23

Where is glycogen stored?

Answer 23

Liver and skeletal muscles.

Question 24

The creation of glucose from non-carbohydrate molecules like proteins and lipids.

Answer 24

Gluconeogenesis

Question 25

What enzyme breaks triglycerides into glycerol and fatty acids?

Answer 25

Lipase

Question 26

What process breaks fatty acids into acetyl CoA?

Answer 26

Beta-Oxidation

Question 27

What does the brain use as a backup energy source when glucose is low?

Answer 27

Ketones

Question 28

When are proteins used as an energy source?

Answer 28

Only when carbohydrates and fats are unavailable.

Question 29

What happens during oxidative deamination?

Answer 29

The amino group is removed from amino acids, and ammonia is converted into urea.

Question 30

Are nucleic acids used for energy?

Answer 30

No, but they can be recycled to form new nucleotides.