Questions and Answers

Which statement about the citric acid cycle is correct? 1. The citric acid cycle oxidizes glucose to carbon dioxide. 2 The citric acid cycle produces most of the ATP that is subsequently used by the electron transport chain. 3 The citric acid cycle depends on the availability of NAD+, which is a product of glycolysis. 4 The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle. 5 The oxidation of compounds by the citric acid cycle requires molecular oxygen.

Which of the following statements about the electron transport chain is NOT correct

A It is located in the inner mitochondrion membrane

B Cytochrome c accepts electrons from complex I

C Cytochrome oxidase (complex IV) accepts electrons from Cytochrome c

D Coenzyme Q accepts electrons from complex I and complex II

Which of the following steps in cellular respiration is associated with release of maximum number of ATP molecules?

A Glycolysis

B Kreb’s cycle

C Oxidative phosphorylation

D Reduction of NADP

Which of the following is the correct sequence of events in cellular respiration?

a. glycolysis, citric acid cycle, electron transport chain

b. glycolysis, preparatory reaction, citric acid cycle, electron transport chain

c. glycolysis, electron transport chain, preparatory reaction

d. citric acid cycle, glycolysis, electron transport chain, preparatory reaction

e. citric acid cycle, electron transport, glycolysis, preparatory reaction

Place the following events of the electron transport chain in order.

Rank the items from the event that occurs first to the event that occurs last.

Oxidation of NADH

Reduction of oxygen and formation of water

Release of energy for

ATP synthesis

Electrons leave the electron transport chain

Electrons enter the electron transport chain

Which of the following events takes place in the electron transport chain? Select one:

a. energy is stored in the form of NADH

b. the harnessing of energy from high-energy electrons derived from glycolysis and the citric acid cycle

c. the breakdown of an acetyl group to carbon dioxide

d. the breakdown of glucose into six carbon dioxide molecules

e. substrate-level phosphorylation

Which of the following events takes place in the electron transport chain?

a) The breakdown of glucose into six carbon dioxide molecules.

b) The breakdown of NADH and FADH2 to carbon dioxide.

c) Harnessing energy from high-energy electrons derived from glycolysis, pyruvate oxidation, and the Krebs cycle.

d) Substrate-level phosphorylation.

The proteins of the ETC are located in the inner mitochondrial membrane. This placement allows the transfer of electrons and the establishment of a proton gradient by pumping protons from the mitochondrial matrix into the intermembrane space. This gradient is then used by ATP synthase, another membrane protein, to produce ATP.

Yes, the ETC requires oxygen to function effectively. Oxygen is the final electron acceptor, and its role ensures the chain’s continuity by preventing the accumulation of electrons in the system. Without oxygen, the chain would cease, stopping ATP production through oxidative phosphorylation, and forcing cells to rely on less efficient processes like anaerobic glycolysis.

The electron transport chain takes place in the inner mitochondrial membrane in eukaryotic cells. This membrane is highly folded into structures called cristae, which increase its surface area, allowing a higher density of the protein complexes and other components involved in electron transfer and ATP synthesis. In prokaryotic cells, the chain is located in the plasma membrane.