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 overall efficiency of oxidative phosphorylation in converting glucose to ATP?

  1. 10%

  2. 20%

  3. 30%

  4. 40%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Oxidative phosphorylation is a highly efficient process, with an overall efficiency of approximately 40%, meaning that around 40% of the energy stored in glucose is converted into ATP.

Multiple choice

Which complex of the electron transport chain is also known as the rotenone-sensitive complex?

  1. Complex I (NADH dehydrogenase)

  2. Complex II (Succinate dehydrogenase)

  3. Complex III (Cytochrome c reductase)

  4. Complex IV (Cytochrome c oxidase)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Complex I, also known as NADH dehydrogenase, is also referred to as the rotenone-sensitive complex because it is inhibited by the chemical rotenone.

Multiple choice

What is the role of the proton gradient in oxidative phosphorylation?

  1. To generate ATP

  2. To transfer electrons

  3. To create a proton gradient

  4. To produce NADH and FADH2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The proton gradient across the inner mitochondrial membrane drives the synthesis of ATP by ATP synthase through a process called chemiosmosis.

Multiple choice

What is the first stage of cellular respiration?

  1. Glycolysis

  2. Krebs Cycle

  3. Electron Transport Chain

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

Glycolysis is the first stage of cellular respiration, where glucose is broken down into two molecules of pyruvate.

Multiple choice

What is the primary function of glycolysis?

  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
C Correct answer
Explanation

The primary function of glycolysis is to generate pyruvate, which is then used in the Krebs Cycle.

Multiple choice

How many molecules of ATP are produced during glycolysis?

  1. 2

  2. 4

  3. 6

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

During glycolysis, 2 molecules of ATP are produced.

Multiple choice

What is the second stage of cellular respiration?

  1. Glycolysis

  2. Krebs Cycle

  3. Electron Transport Chain

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

The Krebs Cycle, also known as the Citric Acid Cycle, is the second stage of cellular respiration.

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.