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!
Certainly! NAHD (nicotinamide adenine dinucleotide) and FADH2 (flavin adenine dinucleotide) are molecules that play a crucial role in cellular respiration, specifically in the process of generating energy.
To understand their role, let's first discuss cellular respiration briefly. Cellular respiration is the metabolic process by which cells convert organic molecules, such as glucose, into energy in the form of ATP (adenosine triphosphate). ATP is the primary source of energy for cellular functions.
During the process of cellular respiration, glucose is broken down through several interconnected metabolic pathways, including glycolysis, the Krebs cycle (also known as the citric acid cycle), and the electron transport chain. These pathways occur in the mitochondria of cells.
Now, let's focus on NAHD and FADH2:
1. NADH (the reduced form of NAD+):
- In glycolysis, glucose is broken down into two molecules of pyruvate. During this process, glucose undergoes a series of chemical reactions, leading to the production of NADH.
- In the Krebs cycle, each pyruvate enters the mitochondria and gets converted to acetyl-CoA. Acetyl-CoA then participates in a series of reactions, releasing carbon dioxide and hydrogen atoms. NAD+ plays a crucial role in accepting these hydrogen atoms, becoming reduced to NADH.
- The NADH molecules formed in glycolysis and the Krebs cycle transfer the high-energy electrons and protons (hydrogen ions) they carry to the electron transport chain.
2. FADH2:
- In the Krebs cycle, some of the reactions involve a molecule called FAD. FAD accepts hydrogen atoms, becoming reduced to FADH2.
- Similar to NADH, FADH2 also carries high-energy electrons and protons to the electron transport chain.
Now, let's discuss their role in the electron transport chain:
The electron transport chain is a series of protein complexes embedded in the inner membrane of the mitochondria. It functions to transfer the high-energy electrons from NADH and FADH2 along a series of redox reactions. As the electrons flow through the protein complexes, they release energy, which is used to pump protons (hydrogen ions) across the membrane, creating a proton gradient.
The final acceptor of these electrons is oxygen, which combines with the protons to form water. This process generates a large amount of energy that is used to produce ATP through a process called oxidative phosphorylation.
In summary, NAHD and FADH2 play a crucial role in cellular respiration by carrying high-energy electrons and protons to the electron transport chain. This process ultimately leads to the production of ATP, the energy currency of the cell.