Can someone please explain the role of NAHD and FADH2 in cellular respiration, I don't understand, no matter how many diagrams/explanations I read.
Thanks!
Of course! Understanding the role of NADH and FADH2 in cellular respiration can be challenging, but I'll do my best to explain it to you. Cellular respiration is the process by which cells convert glucose (a sugar molecule) into energy in the form of ATP (adenosine triphosphate). NADH and FADH2 play crucial roles in this process. Let's break it down step by step:
1. Glycolysis: The first stage of cellular respiration is glycolysis, which occurs in the cytoplasm of the cell. During glycolysis, a molecule of glucose is broken down to produce two molecules of pyruvate. In this process, two molecules of NAD+ (nicotinamide adenine dinucleotide) are converted to two molecules of NADH. The NADH carries high-energy electrons derived from glucose.
2. Citric Acid Cycle (Krebs cycle): After glycolysis, the pyruvate molecules enter the mitochondria (the powerhouse of the cell). In the citric acid cycle, each pyruvate is converted to acetyl-CoA, which enters a series of biochemical reactions. During these reactions, NAD+ and FAD (flavin adenine dinucleotide) accept high-energy electrons from the breakdown of acetyl-CoA. NAD+ is converted to NADH, and FAD is converted to FADH2. These electron carrier molecules, NADH and FADH2, store the electrons for the final stage of cellular respiration.
3. Electron Transport Chain (ETC): The electron transport chain, located in the inner membrane of the mitochondria, is the final stage of cellular respiration. Here, the high-energy electrons carried by NADH and FADH2 are transferred through a series of protein complexes. As electrons move through the protein complexes, energy is released and used to generate ATP. This process is called oxidative phosphorylation. NADH donates its electrons to the first protein complex, generating three molecules of ATP per pair of electrons. FADH2 donates its electrons to the second protein complex, generating two molecules of ATP per pair of electrons.
In summary, NADH and FADH2 act as carriers of high-energy electrons that are produced during the breakdown of glucose. These electron carriers donate their electrons to the electron transport chain, which generates ATP, the energy currency of the cell. Remember, NADH is produced during glycolysis and the citric acid cycle, while FADH2 is only produced during the citric acid cycle.
I hope this explanation clarifies the role of NADH and FADH2 in cellular respiration!