Cellular respiration

• Cells are busy performing cell processes all the time: active transport of many substances needed for their survival, for example
• ATP


  Adenosine triphosphate, the energy currency of cells
• Cells have to make ATP, it doesn't matter what kind of cell you are - prokaryote or eukaryote
• Aerobic cellular respiration


  One way cells can make ATP
• This video is specifically going to go into aerobic cellular respiration in eukaryotic cells
• Mitochondria are going to be kind of a big deal in this aerobic cellular respiration, because some of the process occurs in the mitochondria
• Aerobic cellular respiration


  1. Glycolysis

  2. Pyruvate oxidation

  3. Krebs cycle

  4. Electron transport chain and chemiosmosis
• Glycolysis takes place in the cytoplasm and does not require oxygen
• Glycolysis yields approximately 2 pyruvate, 2 ATP, and 2 NADH molecules
• Pyruvate is transported into the mitochondrial matrix where it is oxidized to acetyl CoA, releasing carbon dioxide and producing 2 NADH
• The Krebs cycle occurs in the mitochondrial matrix and is an aerobic process, producing 2 ATP, 6 NADH, and 2 FADH2
• Electron transport chain and chemiosmosis

  1. Electrons transferred from NADH and FADH2 to protein complexes and electron carriers

  2. Proton gradient generated across inner mitochondrial membrane

  3. Protons flow through ATP synthase, powering it to make ATP

  4. Oxygen is the final electron acceptor, forming water
• The electron transport chain and chemiosmosis step makes a lot more ATP compared to the other two previous steps, with estimates ranging from 26-34 ATP per glucose molecule
• The total net ATP produced from aerobic cellular respiration is estimated to be in the range of 30-38 ATP per glucose molecule
• If there's no oxygen available, some cells can perform fermentation to make ATP
• Cyanide can block a step in the electron transport chain, preventing ATP production, which can be deadly
• There is a demand for increased research on mitochondrial diseases due to the important role of mitochondria in ATP production