In oxidative phosphorylation, what is oxidized and what is phosphorylated?

Verified step by step guidance

1. Understand the process of oxidative phosphorylation: It is the final stage of cellular respiration, occurring in the mitochondria, where energy from electrons is used to produce ATP.
2. Identify what is oxidized: During oxidative phosphorylation, NADH and FADH₂ (electron carriers) are oxidized to NAD⁺ and FAD, respectively, as they donate electrons to the electron transport chain.
3. Explain the role of the electron transport chain: The electrons donated by NADH and FADH₂ move through a series of protein complexes in the inner mitochondrial membrane, releasing energy that is used to pump protons (H⁺) across the membrane, creating a proton gradient.
4. Identify what is phosphorylated: The energy from the proton gradient is used by ATP synthase to phosphorylate ADP (adenosine diphosphate) into ATP (adenosine triphosphate), the primary energy currency of the cell.
5. Summarize the key components: In oxidative phosphorylation, NADH and FADH₂ are oxidized, and ADP is phosphorylated to form ATP, linking the oxidation of electron carriers to the production of energy.

Key Concepts

Oxidative Phosphorylation

Oxidative phosphorylation is a metabolic pathway that occurs in the mitochondria, where ATP is produced as a result of the transfer of electrons from NADH and FADH2 to oxygen via the electron transport chain. This process involves the oxidation of these electron carriers, which releases energy used to pump protons across the mitochondrial membrane, creating a proton gradient.

Oxidation

In the context of oxidative phosphorylation, oxidation refers to the loss of electrons from molecules such as NADH and FADH2. This process is crucial as it allows these molecules to donate electrons to the electron transport chain, ultimately leading to the production of ATP. The oxidized forms of these carriers, NAD+ and FAD, are then recycled back into earlier stages of cellular respiration.

Phosphorylation

Phosphorylation in oxidative phosphorylation specifically refers to the addition of a phosphate group to ADP to form ATP. This process is driven by the energy released from the electron transport chain as protons flow back into the mitochondrial matrix through ATP synthase. This mechanism is known as chemiosmosis, where the energy from the proton gradient is harnessed to synthesize ATP.