What is the role of FADH in Complex 2 of the electron transport chain?

FADH2 is an important electron carrier in the electron transport chain, particularly in Complex II, also known as succinate dehydrogenase. In this complex, FADH2 donates electrons that it has acquired from the Krebs cycle. When FADH2 donates these electrons, it does not release protons (H+) into the inter-membrane space. Instead, the electrons are transferred through the electron transport chain, leading to the production of energy in the form of ATP.

It's essential to understand that FADH2 is involved in the transfer of electrons to the chain, not in directly producing ATP or interacting with oxygen. It does not act as a primary electron acceptor in this context; rather, it donates electrons to the electron transport chain, which ultimately contributes to the generation of a proton gradient that drives ATP synthesis.

Though FADH2 contributes significantly to the overall process of cellular respiration and energy generation, the specific function within Complex II is to donate electrons, which is essential in understanding how energy is harnessed by cells.