Mitochondria Energy Production

This is simplified. Search something up if you want more.

Obviously, Mitochondria produce energy (specifically, ATP) through what we intake: oxygen and things in food. The general process is that the mitochondria uses oxygen to turn glucose, fatty acids, and sometimes amino acids into usable energy, called aerobic respiration.

  The TCA and ETC cycles (tricarboxylic acid and electron transport chains, respectively) take the molecules from the breakdown of food and combine them with oxygen, which produces energy.

  In depth, it is complex. Glucose metabolism, or glycolysis, is an important part/variation. First, the glucose is converted to a compound called pyruvate through some chemical reactions. Pyruvate is then transported into the mitochondrial matrix, where another set of reactions convert it to acetyl-CoA. Then the real stuff happens, because acetyl CoA is the start of the entire TCA cycle, where the last extraction of energy from food is best. This cycle will yield carbon dioxide, which we exhale. It also gives us some different energy molecules, NADH and FADH2. The breakdown of fatty acids also yield acetyl CoA, which goes through the TCA cycle. After this, oxidative phosphorylation begins. It takes place in the mitochondria’s inner membrane. The high energy electrons from NADH and FADH2 are transferred through a series of carriers in the Electron Transport Chain, and ultimately react with oxygen to yield water. With each step in the ETC, the energy released from these electron transfer reactions is used to pump protons to the intermembrane space.

This creates a high concentration of protons between the different membranes and a low concentration in the matrix. This concentration gradient is stored potential energy. The high concentration of protons wants to flow “downstream,” into specialized “channels,” which then create adenosine triphosphate (ATP), the great energy molecule that allows you to be here alive.

  Now, this is probably a lot first time. So, we will model this last part, verbally. We have the ocean, or reservoir, trying to push past the dam (intermembrane space) since it is so dense/heavy. Then, it pushes past the “ATP synthase,” aka the turbines which generate “electricity,” or ATP for the city, or cell.

  You might be wondering about this Electron Transport Chain. It is made from four membrane bound complexes we call proton pumps. Electrons flow down the ETC, where the protons are also pumped. Complex 1 accepts electrons from energy molecule NADH, and passes them to coenzyme QoQ10, which receives electrons from Complex number 2. From then, Q10 passes electrons to Complex 3, which passes them to cytochrome c. Cytochrome c passes electrons to Complex 4. It (Complex 4) then takes the electrons and two hydrogen ions, then reacts them together with oxygen to form water.

And that is the simplified process.