Final answer:
The electron transport chain is the phase of cellular respiration that produces approximately 38 ATP molecules. This process follows glycolysis and the Krebs cycle and is driven by the transfer of electrons through a chain that culminates in the synthesis of ATP through oxidative phosphorylation.
Step-by-step explanation:
The phase of cellular respiration that produces approximately 38 ATP molecules is the electron transport chain. This process begins with glycolysis in the cytoplasm, where a glucose molecule is split into two molecules of pyruvate, yielding a small number of ATP. The pyruvate enters the mitochondrion and is converted into acetyl-CoA, which then enters the Krebs cycle, also known as the Citric Acid Cycle. During the Krebs cycle, NADH and FADH2 molecules are generated, which carry electrons to the electron transport chain located in the inner mitochondrial membrane.
As electrons are transferred along the chain and finally, to oxygen, they release energy. This energy is harnessed to pump protons across the mitochondrial membrane, creating a proton gradient that drives the synthesis of ATP through oxidative phosphorylation. The electron transport chain can yield as many as 34 ATP molecules from one glucose molecule. Along with the ATP produced from glycolysis and the Krebs cycle, the total comes to approximately 38 ATP molecules.