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 name of the molecule that carries high-energy electrons from glycolysis and the Krebs cycle to the electron transport chain?

  1. NADH

  2. FADH2

  3. ATP

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

NADH is the molecule that carries high-energy electrons from glycolysis and the Krebs cycle to the electron transport chain. It is produced during the oxidation of glucose and other organic molecules.

Multiple choice

Which of the following is the name of the enzyme that catalyzes the conversion of pyruvate to acetyl-CoA?

  1. Pyruvate dehydrogenase

  2. Citrate synthase

  3. Aconitase

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

Pyruvate dehydrogenase is the enzyme that catalyzes the conversion of pyruvate to acetyl-CoA. This reaction is the first step of the Krebs cycle.

Multiple choice

What is the name of the molecule that carries high-energy electrons from the electron transport chain to NADH?

  1. FADH2

  2. NADH

  3. ATP

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

FADH2 is the molecule that carries high-energy electrons from the electron transport chain to NADH. It is produced during the oxidation of fatty acids and other organic molecules.

Multiple choice

Which of the following is the name of the enzyme that catalyzes the conversion of isocitrate to α-ketoglutarate?

  1. Isocitrate dehydrogenase

  2. Aconitase

  3. Succinate dehydrogenase

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

Isocitrate dehydrogenase is the enzyme that catalyzes the conversion of isocitrate to α-ketoglutarate. This reaction is the second step of the Krebs cycle.

Multiple choice

What is the name of the molecule that carries high-energy electrons from the electron transport chain to cytochrome c?

  1. NADH

  2. FADH2

  3. ATP

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

Cytochrome c is the molecule that carries high-energy electrons from the electron transport chain to cytochrome c oxidase. It is a small, heme-containing protein that is located in the intermembrane space of mitochondria.

Multiple choice

Which of the following is the name of the enzyme that catalyzes the conversion of succinate to fumarate?

  1. Succinate dehydrogenase

  2. Fumarase

  3. Malate dehydrogenase

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

Succinate dehydrogenase is the enzyme that catalyzes the conversion of succinate to fumarate. This reaction is the fourth step of the Krebs cycle.

Multiple choice

What is the name of the molecule that carries high-energy electrons from the electron transport chain to oxygen?

  1. NADH

  2. FADH2

  3. ATP

  4. Cytochrome c oxidase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Cytochrome c oxidase is the enzyme that catalyzes the transfer of electrons from cytochrome c to oxygen. This reaction is the final step of the electron transport chain and results in the production of water.

Multiple choice

Which of the following is the name of the enzyme that catalyzes the conversion of fumarate to malate?

  1. Fumarase

  2. Malate dehydrogenase

  3. Citrate synthase

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

Fumarase is the enzyme that catalyzes the conversion of fumarate to malate. This reaction is the fifth step of the Krebs cycle.

Multiple choice

What is the name of the molecule that carries high-energy electrons from the electron transport chain to FADH2?

  1. NADH

  2. FADH2

  3. ATP

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

NADH is the molecule that carries high-energy electrons from the electron transport chain to FADH2. It is produced during the oxidation of glucose and other organic molecules.

Multiple choice

Which of the following is the name of the enzyme that catalyzes the conversion of malate to oxaloacetate?

  1. Malate dehydrogenase

  2. Citrate synthase

  3. Aconitase

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

Malate dehydrogenase is the enzyme that catalyzes the conversion of malate to oxaloacetate. This reaction is the sixth and final step of the Krebs cycle.

Multiple choice

What is the importance of metabolic flux analysis in industrial biotechnology?

  1. To identify metabolic bottlenecks and optimize metabolic pathways

  2. To determine the stoichiometry of metabolic reactions

  3. To predict the production of metabolites under different conditions

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Metabolic flux analysis is a powerful tool in industrial biotechnology for identifying metabolic bottlenecks, optimizing metabolic pathways, determining the stoichiometry of metabolic reactions, and predicting the production of metabolites under different conditions, enabling the rational design and engineering of microbial strains for improved product formation.