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.

The electron transport chain (ETC) is a sequence of protein complexes and electron carriers embedded in the inner mitochondrial membrane. These complexes pass electrons derived from NADH and FADH2 (produced in earlier metabolic pathways like glycolysis and the Krebs cycle) through a series of redox reactions. The energy released from these reactions pumps protons across the membrane, creating an electrochemical gradient used to generate ATP.

Oxygen is the final electron acceptor in the electron transport chain. It combines with the electrons and protons at the end of the chain to form water. Without oxygen to accept the electrons, the chain would become backed up, and no further ATP could be produced through this pathway, making oxygen essential for efficient energy production in aerobic organisms.

The main purpose of the ETC is to generate ATP, which cells use for various biological processes. By transferring electrons through protein complexes and pumping protons across the membrane, the chain creates an electrochemical gradient. This gradient powers ATP synthase to produce ATP from ADP and inorganic phosphate. Additionally, the ETC helps regenerate electron carriers (NAD+ and FAD) required for other metabolic pathways.

The electron transport chain is a critical part of cellular respiration that occurs in the mitochondria. It involves a series of proteins and carriers embedded in the inner mitochondrial membrane that transfer electrons derived from food molecules. The process generates a proton gradient, which drives ATP synthesis, enabling cells to efficiently produce energy to sustain vital functions.