Oxidative phosphorylation

Definition

Oxidative phosphorylation is the final stage of cellular respiration where ATP is produced through the electron transport chain and chemiosmosis. This process involves the transfer of electrons from NADH and FADH2 to oxygen, creating a proton gradient that drives ATP synthesis in mitochondria.

5 Must Know Facts For Your Next Test

1. Oxidative phosphorylation accounts for approximately 90% of the ATP generated during cellular respiration.
2. The process occurs in the inner mitochondrial membrane, where electron transport proteins and ATP synthase are located.
3. Oxygen acts as the final electron acceptor in oxidative phosphorylation, forming water when it combines with electrons and protons.
4. The proton gradient created by the electron transport chain is essential for ATP synthesis, as it drives protons back through ATP synthase.
5. Inhibitors or uncouplers can disrupt oxidative phosphorylation, leading to reduced ATP production and potential cell death.

Review Questions

• How does oxidative phosphorylation relate to the production of ATP during cellular respiration?
  • Oxidative phosphorylation is crucial for ATP production during cellular respiration as it generates most of the ATP molecules. It involves the electron transport chain transferring electrons from NADH and FADH2 to oxygen, creating a proton gradient across the inner mitochondrial membrane. This gradient powers ATP synthase to produce ATP from ADP and inorganic phosphate, making oxidative phosphorylation a key step in energy production.
• What role does the electron transport chain play in oxidative phosphorylation, and how does it contribute to cellular energy efficiency?
  • The electron transport chain plays a central role in oxidative phosphorylation by facilitating the transfer of electrons from carriers like NADH and FADH2 to oxygen. As electrons move through the chain, energy is released and used to pump protons into the intermembrane space, creating a strong proton gradient. This process not only enhances energy efficiency by maximizing ATP yield but also ensures that oxygen is effectively utilized as an electron acceptor, which is vital for aerobic organisms.
• Evaluate how disruptions in oxidative phosphorylation can affect cellular metabolism and overall organism health.
  • Disruptions in oxidative phosphorylation can severely impact cellular metabolism and overall organism health by limiting ATP production. When the electron transport chain is inhibited or uncoupled, cells cannot generate sufficient energy needed for various biochemical processes. This can lead to a buildup of metabolic intermediates, reduced energy availability for vital functions, and can ultimately result in cell death or dysfunction. In multicellular organisms, such disruptions can contribute to diseases related to energy metabolism, affecting organ function and overall health.

Related terms

Electron Transport Chain: A series of protein complexes located in the inner mitochondrial membrane that facilitate the transfer of electrons from electron donors to electron acceptors, ultimately leading to ATP production.

Chemiosmosis:

The movement of protons across a membrane down their concentration gradient, which powers ATP synthase to convert ADP and inorganic phosphate into ATP.

NADH:

A coenzyme that acts as an electron carrier in cellular respiration, produced during glycolysis and the citric acid cycle.