What is the role of NADH in cellular respiration?

NADH serves as an electron carrier in cellular respiration, facilitating the transfer of energy within cells.

In the process of cellular respiration, NADH plays a crucial role as an electron carrier. This process is fundamental to all living organisms as it is the primary method by which cells extract energy from nutrients. The energy is stored in the form of adenosine triphosphate (ATP), which is used to power various cellular activities.

Cellular respiration consists of several stages, including glycolysis, the Krebs cycle, and the electron transport chain. NADH is involved in both the glycolysis and the Krebs cycle. During glycolysis, glucose is broken down into two molecules of pyruvate, generating a small amount of ATP and reducing NAD+ to NADH. In the Krebs cycle, the pyruvate is further broken down, producing more NADH.

The NADH molecules produced in these stages then move to the electron transport chain, which is the final stage of cellular respiration. Here, NADH donates its electrons to the first protein complex in the chain. This triggers a series of redox reactions, where electrons are transferred from one molecule to another. These reactions create a flow of protons across the mitochondrial membrane, generating a gradient. The energy from this gradient is used to synthesise ATP from ADP and inorganic phosphate.

In essence, NADH acts as a shuttle, carrying high-energy electrons from glucose and other nutrients to the electron transport chain, where their energy is harnessed to produce ATP. Without NADH, the transfer of energy within cells would not be possible, making it a vital component of cellular respiration.