How Cellular Respiration Powers Your Cells

Cellular respiration begins in the cytoplasm, where glucose molecules undergo their first transformation.Glucose, a six-carbon sugar molecule, is our body's primary energy source.Through a process called glycolysis, this glucose molecule is split into two three-carbon pyruvate molecules.During this process, a small amount of energy is produced in the form of ATP and NADH molecules.Let's break down the key steps of glycolysis. First, glucose enters the process. ATP is used to phosphorylate glucose. Then, the glucose molecule splits into two three-carbon compounds. Finally, energy is captured in the form of ATP and NADH.These pyruvate molecules are now ready to enter the next phase of cellular respiration, which will occur in the mitochondria.These pyruvate molecules will continue their journey in the next phase of cellular respiration.The citric acid cycle occurs inside the mitochondria, the powerhouse of the cell.Pyruvate from glycolysis enters the mitochondria and is converted to acetyl-CoA.This conversion releases a carbon dioxide molecule and produces NADH.Acetyl-CoA then enters the citric acid cycle, also known as the Krebs cycle.Throughout the cycle, several NADH molecules are produced as electrons are transferred from carbon compounds.At one point in the cycle, FADH2 is produced when succinate is converted to fumarate.Carbon dioxide is released at two points in the cycle as the carbon compounds are broken down.The cycle continues to turn, processing more acetyl-CoA and generating more electron carriers.These electron carriers, NADH and FADH2, will deliver their electrons to the electron transport chain in the next stage of cellular respiration.The electron transport chain is located in the inner mitochondrial membrane.The chain consists of four major protein complexes and ATP synthase.NADH and FADH2 from previous steps deliver their high-energy electrons to the chain.As electrons flow through the complexes, their energy is used to pump protons across the membrane.The accumulated protons create a gradient, like water behind a dam. As they flow back through ATP synthase, it rotates like a turbine, producing ATP.This process is highly efficient, producing most of the cell's ATP supply.