FADH2

Definition

FADH2 is a reduced form of flavin adenine dinucleotide, an important electron carrier in cellular respiration. It plays a crucial role in energy production by transporting electrons to the electron transport chain, contributing to the generation of ATP during oxidative phosphorylation.

5 Must Know Facts For Your Next Test

1. FADH2 is produced during the citric acid cycle when succinate is oxidized to fumarate.
2. Each molecule of FADH2 generates approximately 1.5 ATP molecules when it donates electrons to the electron transport chain, which is less than the 2.5 ATP generated from NADH.
3. FADH2 enters the electron transport chain at a lower energy level than NADH, which contributes to its lower ATP yield.
4. In addition to its role in cellular respiration, FADH2 is involved in various biochemical reactions and serves as a cofactor for some enzymes.
5. The conversion of FAD to FADH2 is an essential step in various metabolic pathways, including fatty acid oxidation and amino acid metabolism.

Review Questions

• How does FADH2 contribute to ATP production during cellular respiration?
  • FADH2 contributes to ATP production by acting as an electron carrier that transports high-energy electrons to the electron transport chain. When FADH2 donates its electrons, they move through several protein complexes, leading to the pumping of protons across the inner mitochondrial membrane. This creates a proton gradient that drives ATP synthesis through ATP synthase, ultimately resulting in the production of ATP.
• Compare the roles of FADH2 and NADH in cellular respiration and their impact on ATP yield.
  • Both FADH2 and NADH are crucial for transporting electrons in cellular respiration. However, NADH generates about 2.5 ATP per molecule because it donates its electrons at a higher energy level compared to FADH2, which yields around 1.5 ATP. This difference in entry point into the electron transport chain and energy levels highlights their varying impacts on overall ATP yield during oxidative phosphorylation.
• Evaluate the significance of FADH2's role in metabolic pathways beyond cellular respiration and its implications for overall energy metabolism.
  • FADH2's role extends beyond just cellular respiration; it also participates in various metabolic pathways, including fatty acid oxidation and amino acid metabolism. Its ability to act as a cofactor for certain enzymes allows it to facilitate key biochemical reactions that are essential for maintaining energy balance in cells. Understanding FADH2's broader significance helps highlight its importance not only for energy production but also for regulating various metabolic processes necessary for life.

Related terms

NADH:

NADH is another electron carrier that, like FADH2, plays a significant role in cellular respiration by shuttling electrons to the electron transport chain.

Electron Transport Chain: The electron transport chain is a series of protein complexes located in the inner mitochondrial membrane that transfer electrons from NADH and FADH2 to oxygen, ultimately producing ATP.

Oxidative Phosphorylation: Oxidative phosphorylation is the metabolic pathway where ATP is produced as a result of transferring electrons through the electron transport chain and using the energy released to synthesize ATP.