Cellular Respiration: How Your Body Makes Energy

Welcome to Part 1 of Cellular Respiration, where we'll explore how cells break down glucose to begin the energy production process.Cellular respiration begins with glucose, a six-carbon sugar molecule that we get from the food we eat.The first phase of cellular respiration, called glycolysis, occurs in the cell's cytoplasm. This process involves multiple enzymatic steps.First, glucose is phosphorylated, making it more reactive. Then, the glucose molecule is rearranged into a more unstable form.The unstable six-carbon molecule is then split into two three-carbon compounds.Finally, these three-carbon compounds are modified to form two pyruvate molecules.Throughout this process, the cell captures energy in the form of ATP and NADH. Each glucose molecule yields two ATP molecules and two NADH molecules.While this may seem like a small amount of energy, glycolysis is just the beginning. The pyruvate molecules will continue through the next stages of cellular respiration to generate much more ATP.Inside the mitochondria, pyruvate molecules are transformed into acetyl-CoA.During this conversion, carbon dioxide is released and NADH is produced.The acetyl-CoA then enters the Krebs cycle, a series of eight chemical reactions that form a continuous loop.As molecules move through the cycle, electrons are stripped away and captured by carrier molecules NADH and FADH₂.Throughout the cycle, carbon dioxide is released as a waste product. This CO2 will eventually be exhaled from our lungs.The cycle continues as long as there is more acetyl-CoA to process, generating energy carriers that will be used in the next stage of cellular respiration.The electron transport chain is located in the inner mitochondrial membrane.It consists of four protein complexes and ATP synthase, arranged in a specific sequence.NADH and FADH2 deliver high-energy electrons to the chain.As electrons flow through the complexes, their energy is used to pump protons from the matrix to the intermembrane space.This creates an electrochemical gradient, with a high concentration of protons in the intermembrane space.Protons flow back through ATP synthase, causing it to rotate like a turbine and synthesize ATP.Through this process, one glucose molecule can generate up to thirty-six ATP molecules.This completes the cellular respiration process, efficiently converting the energy from glucose into ATP.