NADH2 and FADH2 Full Form

In the electron transport chain phase of cellular respiration, the chemicals FADH2 and NADH are used to convert oxygen or food molecules into energy. The process of using oxygen and food molecules to produce energy, carbon dioxide, water, and waste products is known as cellular respiration. Respiration is the process through which humans transform food into energy by utilising water and oxygen. Glycolysis, the Krebs cycle, and the electron transport chain are the three metabolic processes of respiration. We won’t go into great depth about these three phases right now. We’ll instead concentrate on two molecules, FADH2 and NADH, and how they’re used in respiration.

NADH and FADH2 play a role in a number of metabolic processes. The Krebs cycle generates both NADH and FADH2. By oxidative phosphorylation, NADH creates three ATP molecules, whereas FADH2 produces two. In the ETS, NADH transports electrons to complex I, while FADH2 transports electrons to complex II. 

What Are FADH2 and NADH?

The redox cofactor FADH2, which stands for Flavin adenine dinucleotide, is generated during the last steps of the electron transport chain process. FADH2, or flavin adenine dinucleotide, is a redox cofactor that is produced throughout the Krebs cycle and used in the electron transport chain, the final stage of respiration. Electrons produced in the Glycolysis and Krebs Cycle are transported to the Electron Transport Chain by a high-energy electron carrier.

Six molecules of NADH and two molecules of FADH2 are created throughout the respiration process. A little amount of energy is created in the form of ATP during the respiration cycle, which is used to synthesise these two molecules through the reduction and oxidation of FAD and NAD+. In the last stage of respiration, when the majority of the energy is lost and created from mitochondria, these two chemicals are utilised in the movement of electrons in the electron transport chain.

Function of NADH and FADH2

In human bodies, NADH and FADH play an important role in cellular energy generation. The food we eat cannot be used directly as a source of energy. Metabolism, which entails a sequence of chemical events, aids in the conversion of energy from meals into energy that our bodies can utilise. This immediately available energy is stored in the nucleotide ATP (adenosine triphosphate). The ATP molecule, often known as the cell’s energy currency, is the primary source of energy storage in cells.

During respiration, reduction-oxidation processes in the Krebs cycle produce FADH2 and NADH from FAD and NAD+, as shown below:

This cycle creates FADH2 and NADH by releasing modest quantities of energy in the form of adenosine triphosphate, or ATP. The Krebs cycle works in a similar way to a wheel. Energy is generated and released every time it completes one full cycle. The NAD+ and FAD are brought in at important times during the cycle and connected to other electrons, resulting in the synthesis of NADH and FADH2, as shown in the diagram.

NADH and FADH2 in Cellular Respiration

The creation of ATP is an important aspect of cellular respiration (the process of creating energy from food), and both NADH and FADH2 are engaged in this process. Every NADH molecule creates 3 ATP molecules during cellular respiration, whereas each FADH2 molecule produces 2 ATP molecules. Glycolysis, acetyl CoA production, Krebs cycle, and electron transport chain are all part of the cellular respiration process. Sugar is broken down in glycolysis to produce pyruvate as the result. Pyruvate is a three-carbon molecule that transforms into acetyl coenzyme-A. (CoA). Acetyl CoA is oxidised in the Krebs cycle, releasing high-energy electrons. NADH and FADH2, respectively, are formed when these electrons and hydrogen atoms mix with NAD+ and FAD molecules.

The electron carriers NADH and FADH2 donate their electrons to the electron transport chain. The electron transport chain is a set of chemical events in which electrons from high-energy molecules like NADH and FADH2 are transferred to low-energy molecules like oxygen (energy acceptors). In cellular respiration and other activities such as photosynthesis, the electron transport chain is the principal source of energy. The electron transport chain is found in the cell’s energy centres, the mitochondrion. The NADH and FADH2 electrons that are displaced are essentially high-energy electrons. The energy released during the transport of these electrons is utilised to create ATP. The electron transport chain, which is indicated by the synthesis of ATP in the inner mitochondrial membrane, is the final stage of cellular respiration.

Conclusion

NADH and FADH2 are responsible for donating electrons to the electron transport chain. During the electron transport chain, they both give electrons by supplying a hydrogen molecule to the oxygen molecule to generate water. The glycolysis and Kreb cycles both produce NADH. Only the Krebs cycle produces FADH2.