kms

Question 1

Where does cellular respiration take place?

Answer 1

Cytoplasm and mitochondria

Glycolysis occurs in the cytoplasm, while the Krebs cycle and the electron transport chain (ETC) occur in the mitochondria.

Question 2

Where does the process of fermentation take place?

Answer 2

Cytoplasm

Fermentation occurs entirely in the cytoplasm.

Question 3

What are the 2 metabolic pathways a cell can use and what does it depend on?

Answer 3

Aerobic respiration and fermentation.

The pathway depends on the availability of oxygen.

Question 4

Sequence of steps of the Fermentation Pathway:

Answer 4

1. Glycolysis. 2. Conversion of pyruvate to either lactic acid or ethanol and carbon dioxide.

Question 5

Sequence of steps of the Cellular Respiration Pathway:

Answer 5

1. Glycolysis. 2. Pyruvate oxidation. 3. Krebs cycle (citric acid cycle). 4. Electron transport chain (ETC) and oxidative phosphorylation.

Question 6

How many molecules of ATP are released during glycolysis?

Answer 6

4 ATP produced, but 2 ATP are consumed, yielding a net gain of 2 ATP.

Question 7

How many molecules of ATP are produced after the entire Fermentation pathway?

Answer 7

2 ATP per glucose.

Question 8

How many molecules of ATP are produced after the entire Cellular Respiration pathway (from 1 molecule of glucose)?

Answer 8

36–38 ATP.

Question 9

How many molecules of ATP are produced from the Krebs cycle for 1 molecule of pyruvic acid?

Answer 9

1 ATP (or GTP) per pyruvate, so 2 ATP per glucose.

Question 10

Lactic Acid Fermentation equation:

Answer 10

Glucose → 2 Lactic acid + 2 ATP.

Question 11

Alcoholic Fermentation equation:

Answer 11

Glucose → 2 Ethanol + 2 CO₂ + 2 ATP.

Question 12

Cellular Respiration equation:

Answer 12

C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + 36–38 ATP.

Question 13

Main reactant and products of Cellular Respiration:

Answer 13

Reactant: Glucose (C₆H₁₂O₆) and oxygen (O₂). Products: Carbon dioxide (CO₂), water (H₂O), and ATP.

Question 14

Molecules involved in glycolysis:

Answer 14

Start: Glucose. End: 2 Pyruvate, 2 NADH, and 2 ATP (net).

Question 15

ATP molecules in glycolysis:

Answer 15

2 ATP required to start. 4 ATP produced, resulting in a net gain of 2 ATP.

Question 16

Reactants and products of glycolysis:

Answer 16

Reactants: Glucose, 2 NAD⁺, 2 ADP, 2 Pi. Products: 2 Pyruvate, 2 NADH, 2 ATP (net), 2 H₂O.

Question 17

What are NAD⁺ and FAD?

Answer 17

NAD⁺ and FAD are electron carriers.

They accept electrons to become NADH and FADH₂, which transport electrons to the ETC.

Question 18

Why does fermentation occur after glycolysis?

Answer 18

To regenerate NAD⁺ so glycolysis can continue in the absence of oxygen.

Question 19

Types of fermentation and examples:

Answer 19

Lactic Acid Fermentation: Occurs in muscles during intense exercise, producing lactic acid. Alcoholic Fermentation: Occurs in yeast, producing ethanol and CO₂.

Question 20

Reactants and products of lactic acid fermentation:

Answer 20

Reactants: Pyruvate, NADH. Products: Lactic acid, NAD⁺.

Question 21

Reactants and products of alcoholic fermentation:

Answer 21

Reactants: Pyruvate, NADH. Products: Ethanol, CO₂, NAD⁺.

Question 22

Starting molecule entering the Krebs cycle:

Answer 22

Acetyl-CoA.

Question 23

Products of the Krebs Cycle per pyruvate:

Answer 23

3 NADH, 1 FADH₂, 1 ATP (or GTP), 2 CO₂.

Question 24

Products of the Krebs Cycle per glucose:

Answer 24

6 NADH, 2 FADH₂, 2 ATP (or GTP), 4 CO₂.

Question 25

Main purpose of the Krebs cycle:

Answer 25

To generate high-energy electron carriers (NADH, FADH₂) for the ETC.

Question 26

Where do NADH and FADH₂ go after the Krebs cycle?

Answer 26

To the electron transport chain in the inner mitochondrial membrane.

Question 27

What happens to the electrons in the electron carriers?

Answer 27

They are transferred through the ETC, driving proton pumps and creating a proton gradient.

Question 28

ATP from each electron pair:

Answer 28

NADH: ~2.5 ATP. FADH₂: ~1.5 ATP.

Question 29

Energy from the ETC is used to:

Answer 29

Pump protons across the inner mitochondrial membrane, creating a gradient for ATP synthesis.

Question 30

Role of ATP synthase:

Answer 30

ATP synthase uses the proton gradient to convert ADP + Pi into ATP during oxidative phosphorylation.

Question 31

Correct sequence of cellular respiration:

Answer 31

1. Glycolysis. 2. Pyruvate oxidation. 3. Krebs cycle. 4. Electron transport chain and oxidative phosphorylation.

Question 32

Energy sources during a workout:

Answer 32

1. First few seconds: Stored ATP. 2. 10–30 seconds: Creatine phosphate. 3. Minutes: Glycolysis and lactic acid fermentation. 4. Prolonged exercise: Aerobic respiration (carbohydrates, fats).