Biology

Cellular Respiration and Enzymes

1,721 Questions

Explore key concepts of cellular respiration, including glycolysis, the Krebs cycle, and the electron transport chain. These questions also cover ATP production, anaerobic respiration, and essential metabolic pathways. This topic forms a core part of the biology syllabus for many competitive examinations.

Glycolysis and metabolic pathwaysKrebs cycle processesElectron transport chainATP production countAnaerobic respiration products

Cellular Respiration and Enzymes Questions

Multiple choice

What is the primary function of the Krebs Cycle?

  1. To produce ATP

  2. To produce NADH and FADH2

  3. To generate pyruvate

  4. To release carbon dioxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The primary function of the Krebs Cycle is to produce NADH and FADH2, which are high-energy electron carriers.

Multiple choice

How many molecules of ATP are produced during the Krebs Cycle?

  1. 2

  2. 4

  3. 6

  4. 8
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During the Krebs Cycle, 2 molecules of ATP are produced.

Multiple choice

What is the third stage of cellular respiration?

  1. Glycolysis

  2. Krebs Cycle

  3. Electron Transport Chain

  4. Oxidative Phosphorylation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Electron Transport Chain is the third stage of cellular respiration.

Multiple choice

What is the primary function of the Electron Transport Chain?

  1. To produce ATP

  2. To produce NADH and FADH2

  3. To generate pyruvate

  4. To release carbon dioxide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The primary function of the Electron Transport Chain is to produce ATP through a process called oxidative phosphorylation.

Multiple choice

How many molecules of ATP are produced during the Electron Transport Chain?

  1. 32

  2. 34

  3. 36

  4. 38
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During the Electron Transport Chain, 32 molecules of ATP are produced.

Multiple choice

What is the final stage of cellular respiration?

  1. Glycolysis

  2. Krebs Cycle

  3. Electron Transport Chain

  4. Oxidative Phosphorylation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Oxidative Phosphorylation is the final stage of cellular respiration.

Multiple choice

What is the primary function of oxidative phosphorylation?

  1. To produce ATP

  2. To produce NADH and FADH2

  3. To generate pyruvate

  4. To release carbon dioxide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The primary function of oxidative phosphorylation is to produce ATP through the transfer of electrons from NADH and FADH2 to oxygen.

Multiple choice

How many molecules of ATP are produced during oxidative phosphorylation?

  1. 2

  2. 4

  3. 6

  4. 8
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

During oxidative phosphorylation, 32 molecules of ATP are produced.

Multiple choice

What is the total number of ATP molecules produced during cellular respiration?

  1. 36

  2. 38

  3. 40

  4. 42
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During cellular respiration, a total of 38 molecules of ATP are produced.

Multiple choice

Which molecule is the final electron acceptor in the Electron Transport Chain?

  1. Oxygen

  2. Hydrogen

  3. Carbon Dioxide

  4. Glucose
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Oxygen is the final electron acceptor in the Electron Transport Chain.

Multiple choice

What is the name of the molecule that carries high-energy electrons from glycolysis to the Krebs Cycle?

  1. Pyruvate

  2. Acetyl CoA

  3. NADH

  4. FADH2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Acetyl CoA is the molecule that carries high-energy electrons from glycolysis to the Krebs Cycle.

Multiple choice

Which enzyme is responsible for the initial phosphorylation of glucose in glycogenesis?

  1. hexokinase

  2. glucokinase

  3. phosphofructokinase

  4. pyruvate kinase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Glucokinase is the enzyme that catalyzes the phosphorylation of glucose to glucose-6-phosphate, the first step in glycogenesis.

Multiple choice

Which enzyme catalyzes the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate?

  1. phosphofructokinase

  2. fructose-1,6-bisphosphatase

  3. aldolase

  4. triose phosphate isomerase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Phosphofructokinase catalyzes the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate.

Multiple choice

Which enzyme catalyzes the isomerization of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate?

  1. triose phosphate isomerase

  2. aldolase

  3. glyceraldehyde-3-phosphate dehydrogenase

  4. phosphoglycerate kinase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Triose phosphate isomerase catalyzes the isomerization of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate.

Multiple choice

What is the role of glyceraldehyde-3-phosphate dehydrogenase in glycogenesis?

  1. converts glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate

  2. converts 1,3-bisphosphoglycerate to glyceraldehyde-3-phosphate

  3. converts dihydroxyacetone phosphate to glyceraldehyde-3-phosphate

  4. converts fructose-1,6-bisphosphate to dihydroxyacetone phosphate and glyceraldehyde-3-phosphate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Glyceraldehyde-3-phosphate dehydrogenase catalyzes the oxidation of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate.