Cellular Respiration
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What is Cellular Respiration?
Cellular respiration is the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen to produce energy. The process is represented by this formula: O2+C6 H12 O6 ---> CO2 + H2O + ATP. Cellular respiration occurs in the mitochondria.
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This photo represents the relationship between photosynthesis and cellular respiration. Photosynthesis provides the Oxygen (O2) and Glucose (C6H12O2) for cellular respiration. Then cellular respiration uses those reactants to make Carbon- Dioxide (CO2) and H2O, which are reactants for Photosynthesis.
Structure of Mitochondriamitochondira.jpgThe Two Types of Cellular Respiration:
  • Aerobic Respiration:
  • requires oxygen.
  • occurs in the mitochondria.
  • the more efficient way of producing energy, because it produces from 36- 38 ATP per glucose, as oppose to Anaerobic which only produes 2 ATP per glucose.
  • occurs in three steps: gylcolysis, krebs cycle and the elctron transport chain.
    • Glycolysis:
      • Glycolysis takes place in the cytoplasm and is the first step to both aerobic and anaerobic respiration. It is the process that turns it's reactant, glucose, into it's product, pyruvate and 2 ATP. The goal of this process is simply just the first step of releasing energy. Once glycolysis produces the pyruvate, the pyruvate is transported inside the mitochondria and is then converted into Acetyl Co-A, where it proceeds into the Krebs Cycle.
    • Krebs Cycle:
      • The Krebs Cycle, also known as the 'Citric Acid Cycle' occurs in the mitochondria's matrix. The Krebs Cycle works by taking its reactant from glycolysis, Acetyl Co-A, and produces energy carriers, 2 ATP, NADH, FADH2, and it's waste product, CO-2.
    • Electron Transport Chain:
      • The Electron Trasport Chain (ETC) is the third, and final step of aerobic respiration. It takes place in the mitochondira's cristae. By using it's reactants from the Krebs Cycle, NADH and FADH2, the Electron Transport Chain produces 34 ATP and a waste product of water. Electrons are released from the energy carriers, and the energy from the electrons is used to make the ATP.
        aerobic_respiration.jpg
        This photo shows how glycolisis, the krebs cycle, and electron transport chain all work together to form the aerobic respiration process. The goal of all of them is to produce more energy.

  • Aneraerobic Respiration:
  • Otherwise known as, Fermentation.
  • Takes place in the absence of oxygen.
  • Two Types:
    • Alcoholic Fermentation:
      • Who uses this? Yeast.
      • Where does this occur? In the cytoplasm.
      • Reactants: Glucose.
      • Products: 2 ATP, CO2 and Ethanol
    alc.jpg
    This shows Alcoholic Fermentation.
    • Lactic Acid Fermentation
      • Who uses this? Certain types of bacteria, animal muscle cells.
      • Where does this occur? Cytoplasm.
      • Reactants: Glucose.
      • Products: 2 ATP and Lactate.
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This is the process of Lactic Acid Fermentation