Fadh2

Definition

FADH2, or flavin adenine dinucleotide in its reduced form, is a crucial electron carrier in cellular metabolism that plays a vital role in energy production. It is produced during several metabolic pathways, including the citric acid cycle (Krebs cycle) and the beta-oxidation of fatty acids. FADH2 contributes to the generation of ATP through oxidative phosphorylation in the mitochondria, ultimately powering various cellular processes.

5 Must Know Facts For Your Next Test

1. FADH2 is generated during the conversion of succinate to fumarate in the citric acid cycle, where it acts as a cofactor for the enzyme succinate dehydrogenase.
2. Unlike NADH, which donates electrons to Complex I of the electron transport chain, FADH2 donates electrons to Complex II, resulting in less ATP production per molecule.
3. Each molecule of FADH2 can produce approximately 1.5 ATP when processed through the electron transport chain.
4. FADH2 is not only involved in energy metabolism but also participates in redox reactions and the detoxification of reactive oxygen species.
5. Deficiencies in FAD or issues with FADH2 metabolism can lead to various metabolic disorders affecting energy production.

Review Questions

• How does FADH2 contribute to ATP production during cellular respiration?
  • FADH2 contributes to ATP production by donating electrons to Complex II of the electron transport chain. This transfer of electrons leads to a series of redox reactions that ultimately pump protons into the intermembrane space, creating a proton gradient. As protons flow back into the mitochondrial matrix through ATP synthase, ATP is synthesized. The energy yield from FADH2 is slightly lower than that from NADH, producing approximately 1.5 ATP molecules per FADH2.
• Compare and contrast the roles of FADH2 and NADH in cellular metabolism.
  • FADH2 and NADH are both crucial electron carriers in cellular metabolism, but they differ in their sources and efficiency in ATP production. FADH2 is generated mainly during the citric acid cycle and beta-oxidation, while NADH is produced during glycolysis and other pathways. Additionally, FADH2 donates electrons at Complex II of the electron transport chain, resulting in a lower ATP yield compared to NADH, which donates electrons at Complex I. This difference impacts how effectively cells can convert energy stored in nutrients into usable ATP.
• Evaluate the significance of FADH2 in relation to metabolic disorders affecting energy production.
  • FADH2 plays a critical role in energy metabolism, and disruptions in its production or utilization can lead to metabolic disorders. For instance, deficiencies in enzymes involved in generating FADH2 may impair the citric acid cycle or fatty acid oxidation, resulting in decreased ATP production and energy deficits. Such conditions can manifest as muscle weakness, fatigue, or more severe metabolic disturbances. Understanding FADH2's role helps highlight potential therapeutic targets for managing these metabolic disorders and improving energy homeostasis.

Related terms

NADH:

NADH, or nicotinamide adenine dinucleotide in its reduced form, is another key electron carrier that functions similarly to FADH2, providing electrons to the electron transport chain for ATP production.

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 generate ATP through oxidative phosphorylation.

Oxidative Phosphorylation: Oxidative phosphorylation is the metabolic process by which cells generate ATP using energy derived from the transfer of electrons through the electron transport chain.