Oxidative phosphorylation

Definition

Oxidative phosphorylation is a metabolic process that occurs in the mitochondria, where adenosine triphosphate (ATP) is generated through the transfer of electrons from electron donors to electron acceptors via a series of redox reactions. This process is essential for energy production in aerobic organisms, coupling the electron transport chain with chemiosmosis to create a proton gradient that drives ATP synthesis.

5 Must Know Facts For Your Next Test

1. Oxidative phosphorylation accounts for approximately 90% of the total ATP produced during cellular respiration.
2. The process involves the reduction of oxygen to form water, which is critical for maintaining the flow of electrons through the electron transport chain.
3. ATP synthase is the enzyme responsible for synthesizing ATP from ADP and inorganic phosphate, utilizing the energy derived from the proton gradient created by oxidative phosphorylation.
4. Dysfunction in oxidative phosphorylation can lead to various diseases, including mitochondrial disorders and certain neurodegenerative diseases.
5. Inhibitors of oxidative phosphorylation, such as cyanide, can be lethal as they prevent ATP production by blocking electron transport and oxygen utilization.

Review Questions

• How does oxidative phosphorylation relate to the overall process of cellular respiration?
  • Oxidative phosphorylation is the final stage of cellular respiration, following glycolysis and the citric acid cycle. During this stage, high-energy electrons from NADH and FADH2 are transferred through the electron transport chain located in the mitochondria. The energy released during these transfers is used to pump protons across the mitochondrial membrane, creating a proton gradient that drives ATP synthesis through chemiosmosis.
• Discuss the role of oxygen in oxidative phosphorylation and its significance in aerobic respiration.
  • Oxygen acts as the final electron acceptor in oxidative phosphorylation, receiving electrons from the electron transport chain. This reduction of oxygen forms water, which is essential for maintaining the flow of electrons through the chain. Without oxygen, the entire process halts, leading to a significant decrease in ATP production and potentially causing cellular death due to energy deprivation.
• Evaluate the impact of mitochondrial dysfunction on oxidative phosphorylation and its broader implications for cellular health.
  • Mitochondrial dysfunction can severely impair oxidative phosphorylation, resulting in decreased ATP production and increased production of reactive oxygen species. This dysfunction may lead to energy deficits in cells, contributing to conditions such as muscle weakness, neurodegeneration, and metabolic disorders. The consequences extend beyond individual cells, affecting overall tissue function and potentially leading to systemic health issues.

Related terms

Electron Transport Chain: A series of protein complexes located in the inner mitochondrial membrane that transfer electrons and pump protons to generate a proton gradient.

Chemiosmosis: The movement of protons across a membrane during cellular respiration, which generates ATP through the enzyme ATP synthase.

Mitochondria: Organelles known as the powerhouses of the cell, where oxidative phosphorylation and other metabolic processes occur.