Oxidative Phosphorylation

Definition

Oxidative phosphorylation is the metabolic pathway that generates ATP from ADP and inorganic phosphate through the electron transport chain and chemiosmosis, using oxygen as the final electron acceptor. This process takes place in the mitochondria and is a critical part of cellular respiration, linking the oxidation of nutrients with the production of energy.

5 Must Know Facts For Your Next Test

1. Oxidative phosphorylation is responsible for producing about 90% of the ATP generated during cellular respiration, making it crucial for energy metabolism.
2. The process begins when electrons from NADH and FADH2 are transferred through the electron transport chain, which pumps protons into the intermembrane space of mitochondria.
3. Oxygen is essential for oxidative phosphorylation as it serves as the final electron acceptor, forming water when it combines with electrons and protons.
4. The proton gradient created across the inner mitochondrial membrane drives protons back into the mitochondrial matrix through ATP synthase, producing ATP.
5. Inhibition of oxidative phosphorylation can lead to decreased ATP production and may result in cell death, highlighting its vital role in cellular energy homeostasis.

Review Questions

• How does oxidative phosphorylation connect to other metabolic pathways involved in cellular respiration?
  • Oxidative phosphorylation is intricately linked to glycolysis and the citric acid cycle (Krebs cycle) through its reliance on NADH and FADH2 produced during these processes. Glycolysis breaks down glucose to pyruvate, generating NADH, while the citric acid cycle further oxidizes pyruvate derivatives, also generating NADH and FADH2. These electron carriers then feed their electrons into the electron transport chain during oxidative phosphorylation, illustrating a clear flow of energy through metabolic pathways.
• Evaluate the role of oxygen in oxidative phosphorylation and its importance in aerobic metabolism.
  • Oxygen plays a crucial role in oxidative phosphorylation as it acts as the terminal electron acceptor in the electron transport chain. This function allows for efficient transfer of electrons that ultimately leads to the pumping of protons across the inner mitochondrial membrane. In aerobic metabolism, oxygen's presence enables organisms to produce a significant amount of ATP compared to anaerobic processes. Without oxygen, the electron transport chain would become backed up, halting ATP production and leading to cellular energy deficiency.
• Analyze how disruptions in oxidative phosphorylation can affect overall cellular metabolism and health.
  • Disruptions in oxidative phosphorylation can severely impact cellular metabolism by reducing ATP production, which is essential for numerous cellular functions such as biosynthesis, signal transduction, and maintenance of ion gradients. Such disruptions may arise from mitochondrial diseases or exposure to toxins that inhibit components of the electron transport chain. The resultant energy deficit can lead to cellular dysfunction, contributing to a range of health issues including neurodegenerative diseases, muscle weakness, and metabolic disorders. Therefore, maintaining healthy oxidative phosphorylation is vital for overall health.

Related terms

Electron Transport Chain: A series of protein complexes located in the inner mitochondrial membrane that transfer electrons from electron donors to electron acceptors via redox reactions, creating a proton gradient.

Chemiosmosis: The movement of protons across a membrane, which drives the synthesis of ATP via ATP synthase, fueled by the proton gradient established during oxidative phosphorylation.

ATP Synthase: An enzyme that catalyzes the conversion of ADP and inorganic phosphate into ATP using the energy derived from the proton gradient created by the electron transport chain.