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 are some examples of chemical signals used by organisms?

  1. Pheromones

  2. Hormones

  3. Neurotransmitters

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

Chemical signals used by organisms include pheromones, hormones, and neurotransmitters. Pheromones are chemical signals that are released by an organism to communicate with other members of the same species. Hormones are chemical signals that are produced by glands and travel through the bloodstream to target cells. Neurotransmitters are chemical signals that are released by neurons to communicate with other neurons.

Multiple choice

What is the process by which carbohydrates are broken down into glucose?

  1. Glycolysis

  2. Gluconeogenesis

  3. Glycogenolysis

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

Glycolysis is the process by which carbohydrates are broken down into glucose. It occurs in the cytoplasm of cells.

Multiple choice

What is the process by which glucose is converted into energy?

  1. Glycolysis

  2. Gluconeogenesis

  3. Glycogenolysis

  4. Krebs cycle
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The Krebs cycle is the process by which glucose is converted into energy. It occurs in the mitochondria of cells.

Multiple choice

What is the process by which glucose is released from the liver and muscles?

  1. Glycolysis

  2. Gluconeogenesis

  3. Glycogenolysis

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

Glycogenolysis is the process by which glucose is released from the liver and muscles. It occurs when blood sugar levels are low.

Multiple choice

What is the primary role of the electron transport chain in cellular respiration?

  1. To generate ATP

  2. To produce NADH and FADH2

  3. To transport electrons from NADH and FADH2 to oxygen

  4. To create a proton gradient across the inner mitochondrial membrane
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The electron transport chain's main function is to transfer electrons from NADH and FADH2, generated during glycolysis and the Krebs cycle, to oxygen, the final electron acceptor.

Multiple choice

What is the first complex of the electron transport chain?

  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 the first enzyme complex in the electron transport chain that receives electrons from NADH generated during glycolysis and the Krebs cycle.

Multiple choice

What is the role of coenzymes Q and cytochrome c in the electron transport chain?

  1. They act as electron carriers

  2. They generate ATP

  3. They create a proton gradient

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

Coenzyme Q and cytochrome c are mobile electron carriers that transfer electrons between the different complexes of the electron transport chain.

Multiple choice

Which complex of the electron transport chain pumps protons across the inner mitochondrial membrane?

  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
C Correct answer
Explanation

Complex III, also known as cytochrome c reductase, pumps protons across the inner mitochondrial membrane, contributing to the proton gradient necessary for ATP synthesis.

Multiple choice

What is the final electron acceptor in the electron transport chain?

  1. NADH

  2. FADH2

  3. Oxygen

  4. Coenzyme Q
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Oxygen is the final electron acceptor in the electron transport chain, receiving electrons from cytochrome c oxidase and combining with protons to form water.

Multiple choice

What is the process of ATP synthesis coupled to the electron transport chain called?

  1. Oxidative phosphorylation

  2. Glycolysis

  3. Krebs cycle

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

Oxidative phosphorylation is the process by which ATP is synthesized in the mitochondria using the energy released from the electron transport chain.

Multiple choice

What is the role of ATP synthase in oxidative phosphorylation?

  1. To generate a proton gradient

  2. To transfer electrons

  3. To synthesize ATP

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

ATP synthase is an enzyme complex located in the inner mitochondrial membrane that uses the energy from the proton gradient to synthesize ATP from ADP and inorganic phosphate.

Multiple choice

How many ATP molecules are produced per glucose molecule during oxidative phosphorylation?

  1. 2

  2. 10

  3. 32

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

During oxidative phosphorylation, approximately 32 ATP molecules are produced per glucose molecule, representing the majority of ATP generated during cellular respiration.

Multiple choice

What is the significance of the electron transport chain in cellular respiration?

  1. It generates most of the ATP in the cell

  2. It produces NADH and FADH2

  3. It creates a proton gradient

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

The electron transport chain is crucial in cellular respiration as it generates most of the ATP, produces NADH and FADH2, and creates a proton gradient, which are all essential for energy production.

Multiple choice

Which complex of the electron transport chain contains iron-sulfur proteins?

  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, contains iron-sulfur proteins that participate in the transfer of electrons from NADH to coenzyme Q.

Multiple choice

What is the role of cytochrome c oxidase in the electron transport chain?

  1. To transfer electrons from cytochrome c to oxygen

  2. To generate a proton gradient

  3. To synthesize ATP

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

Cytochrome c oxidase is the final enzyme complex in the electron transport chain that transfers electrons from cytochrome c to oxygen, the final electron acceptor.