Which process occurs in the mitochondria during cellular respiration?

The electron transport chain is indeed the process that occurs in the mitochondria during cellular respiration. This stage takes place in the inner mitochondrial membrane and is critical for the production of adenosine triphosphate (ATP), the energy currency of the cell.

During the electron transport chain, electrons are transferred through a series of protein complexes, known as electron carriers. These electrons come from the reduced coenzymes, NADH and FADH2, which are generated during earlier stages of cellular respiration, specifically during glycolysis and the Krebs cycle. As electrons move through the chain, they release energy, which is used to pump protons (H⁺ ions) into the intermembrane space of the mitochondria. This creates a proton gradient, which ultimately drives ATP synthesis through a process called chemiosmosis via ATP synthase. This production of ATP is the primary goal of cellular respiration, making the electron transport chain a vital step in generating energy for cellular activities.

In contrast, glycolysis occurs in the cytoplasm and is the first step of cellular respiration, fermentation is an anaerobic process that does not require mitochondria, and decarboxylation of glucose does not specifically refer to a process occurring in the mitochondria but involves