What is the role of NADH and FADH2 in the electron transport chain?

NADH and FADH2 act as electron carriers in the electron transport chain, transferring high-energy electrons to power ATP production.

NADH and FADH2 are crucial components of cellular respiration, specifically in the process known as the electron transport chain (ETC). The ETC is the final stage of cellular respiration, where the majority of ATP (adenosine triphosphate) is produced. ATP is the primary energy currency of the cell, used to power various cellular processes.

NADH and FADH2 are produced in earlier stages of cellular respiration, namely glycolysis, the Krebs cycle, and the transition reaction. During these stages, glucose and other molecules are broken down, and in the process, high-energy electrons are transferred to NAD+ and FAD, forming NADH and FADH2. These molecules are then used in the ETC to transfer these high-energy electrons to a series of protein complexes located in the inner mitochondrial membrane.

The role of NADH and FADH2 in the ETC is to donate these high-energy electrons to the first protein complex in the chain. As these electrons are passed along the chain, they lose energy, which is used to pump protons (H+ ions) across the mitochondrial membrane, creating a proton gradient. This gradient is then used to power ATP synthase, an enzyme that synthesises ATP from ADP and inorganic phosphate.

In summary, NADH and FADH2 play a vital role in the ETC as electron carriers. They transfer the high-energy electrons obtained from the breakdown of glucose and other molecules to the ETC, where the energy is used to create a proton gradient. This gradient is then used to power the production of ATP, the cell's main source of energy. Without NADH and FADH2, the ETC would not function, and ATP production would be severely impaired, affecting the cell's ability to carry out its functions.