the procces in witch an animals cells use oxygen and digested food molecules to release an energy in is called?
The process you are referring to is called cellular respiration. It is a series of metabolic reactions that occur in the cells of animals (as well as plants and some microorganisms) to generate energy in the form of ATP (adenosine triphosphate). To explain how this process works, let's break it down into three main steps:
1. Glycolysis: This is the initial step of cellular respiration that occurs in the cytoplasm of the cell. Glucose (a type of sugar) is broken down into two molecules of pyruvate. This process also generates a small amount of ATP and NADH (a coenzyme).
2. Krebs cycle (or citric acid cycle): The pyruvate molecules produced in glycolysis are transported into the mitochondria, where they undergo further reactions. In the Krebs cycle, each pyruvate is fully oxidized, releasing carbon dioxide, generating ATP, NADH, and FADH2 (another coenzyme).
3. Electron transport chain (ETC): The NADH and FADH2 molecules produced in glycolysis and the Krebs cycle carry high-energy electrons to the inner membrane of the mitochondria. The ETC is a series of protein complexes that transfer these electrons along with protons across the membrane, creating an electrochemical gradient. As the electrons move through the ETC, energy is released and used to produce a large amount of ATP through a process called oxidative phosphorylation. At the end of the ETC, oxygen acts as the final electron acceptor, combining with hydrogen ions to form water.
Overall, cellular respiration is a vital process that allows cells to convert the potential energy stored in glucose and other fuel molecules into a more usable form of energy, ATP. It is essential for the survival and functioning of organisms.