Biology

Cellular Respiration and Enzymes

1,551 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 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.

Multiple choice

Which enzyme catalyzes the phosphorylation of 1,3-bisphosphoglycerate to 3-phosphoglycerate?

  1. phosphoglycerate kinase

  2. glyceraldehyde-3-phosphate dehydrogenase

  3. triose phosphate isomerase

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

Phosphoglycerate kinase catalyzes the phosphorylation of 1,3-bisphosphoglycerate to 3-phosphoglycerate.

Multiple choice

What is the role of phosphoglycerate mutase in glycogenesis?

  1. converts 3-phosphoglycerate to 2-phosphoglycerate

  2. converts 2-phosphoglycerate to 3-phosphoglycerate

  3. converts phosphoenolpyruvate to pyruvate

  4. converts pyruvate to phosphoenolpyruvate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Phosphoglycerate mutase catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate.

Multiple choice

Which enzyme catalyzes the dehydration of 2-phosphoglycerate to phosphoenolpyruvate?

  1. enolase

  2. phosphoglycerate kinase

  3. phosphoglycerate mutase

  4. glyceraldehyde-3-phosphate dehydrogenase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Enolase catalyzes the dehydration of 2-phosphoglycerate to phosphoenolpyruvate.

Multiple choice

What is the role of pyruvate kinase in glycogenesis?

  1. converts phosphoenolpyruvate to pyruvate

  2. converts pyruvate to phosphoenolpyruvate

  3. converts glucose-6-phosphate to fructose-6-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

Pyruvate kinase catalyzes the conversion of phosphoenolpyruvate to pyruvate.

Multiple choice

Which enzyme catalyzes the transfer of the glycosyl unit from UDP-glucose to glycogen?

  1. glycogen synthase

  2. glycogen phosphorylase

  3. glycogen branching enzyme

  4. glycogen debranching enzyme
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Glycogen synthase catalyzes the transfer of the glycosyl unit from UDP-glucose to glycogen.

Multiple choice

What is the role of glycogen branching enzyme in glycogenesis?

  1. creates branch points in the glycogen molecule

  2. removes branch points from the glycogen molecule

  3. transfers the glycosyl unit from UDP-glucose to glycogen

  4. converts glucose-6-phosphate to fructose-6-phosphate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Glycogen branching enzyme creates branch points in the glycogen molecule.

Multiple choice

Which enzyme catalyzes the removal of branch points from the glycogen molecule?

  1. glycogen debranching enzyme

  2. glycogen branching enzyme

  3. glycogen synthase

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

Glycogen debranching enzyme catalyzes the removal of branch points from the glycogen molecule.

Multiple choice

What is the role of glycogen phosphorylase in glycogenesis?

  1. catalyzes the breakdown of glycogen to glucose-1-phosphate

  2. catalyzes the synthesis of glycogen from glucose-1-phosphate

  3. creates branch points in the glycogen molecule

  4. removes branch points from the glycogen molecule
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Glycogen phosphorylase catalyzes the breakdown of glycogen to glucose-1-phosphate.