Atmungskette / Oxidative Phosphorylierung / Chemiosmose - [Zellatmung, 5/6] - [Biologie, Oberstufe]

This video discusses the process of oxidative phosphorylation, the final step in cellular respiration. The terms respiratory chain and chemiosmosis, which some of you may have searched for, are also closely related to this process. The entire process of ATP synthesis, which occurs in the presence of oxygen, is called oxidative phosphorylation. (Remember that even in the absence of oxygen, under anaerobic conditions, the cell has ways of generating energy, but these result in a low energy yield of ATP.) The process of oxidative phosphorylation, which takes place in the inner mitochondrial matrix, consists of two steps, which can be summarized as follows: Electron transport: The molecules NADH and FADH2, which were produced in the previous steps of cellular respiration and capture the electrons released by the glucose molecule during oxidation, are reintroduced at this point. Both molecules then donate their electrons. These electrons flow through a series of different protein complexes in what is known as the electron transport chain or respiratory chain. This electron flow drives the active transport of hydrogen protons (protons because they are positively charged) from the mitochondrial matrix across the membrane into the intermembrane space. This creates a concentration difference (concentration gradient) on both sides of the membrane: many protons outside the membrane, few protons inside. Chemiosmosis: If there were no mechanism that allowed the positively charged hydrogen atoms to return to the mitochondrial membrane, the aforementioned concentration gradient between the two sides of the membrane would continue to widen. Such a mechanism exists: Via a channel protein—ATP synthase—the protons can diffuse back into the mitochondrial matrix, following their concentration gradient (i.e., from the area of ​​higher concentration to the area of ​​lower concentration). The diffusion of H+ ions is coupled to the synthesis of ATP. Chemiosmosis The exact process of oxidative phosphorylation, with its two sub-steps, is discussed in detail in the video :)