Chapter 4: Respiration

• Respiration definition

  The chemical process involving a series of chemical reactions that break down nutrient molecules (e.g. glucose) in living cells to release energy
• Types of Respiration

  Anaerobic Respiration

  Aerobic Respiration
• What is Aerobic Respiration

  Using oxygen to break down glucose

  Energy is released in organelles called mitochondria

  Glucose + oxygen → carbon dioxide + water (+ energy)

  C6H12O6 + 6O2 → 6CO2 + 6H2O (+ 36-38 ATP)
• What is Anaerobic Respiration

  Release of energy from glucose in the absence of oxygen

  Occurs when there is not enough oxygen to supply for aerobic respiration

  Short-term energy supply

  Glucose → lactic acid (+ energy)

  C6H12O6 → 2C3H6O3 (+ 2 ATP)
• Anaerobic Respiration - Lactic Acid (Intro)


  It can slowly poison your muscles and cause cramps

  Must be removed from the body

  Continue breathing faster and deeper after vigorous exercise

  Extra O2 to break down lactic acid (oxygen debt)
• Anaerobic Respiration in Yeast

  Yeast respires anaerobically when oxygen is absent

  Produces alcohol and carbon dioxide

  Fermentation

  
  

  Glucose → ethanol + carbon dioxide (+ energy)

  C6H12O6 → 2C2H5OH + 2CO2 (+ energy)
• Using Anaerobic Respiration (Yeast)


  Brewing - Barley grains are used as a source of sugar in beer production

  Glucose → ethanol + carbon dioxide (+ energy)

  C6H12O6 → 2C2H5OH + 2CO2 (+ energy)
• Breadmaking in Anaerobic Respiration


  The dough is mixture of flour, water, salt, sugar, and yeast

  CO2 bubbles are trapped inside the dough causing it to rise

  Heat causes alcohol to evaporate
• Unit for energy in Respiration

  ATP (adenosine triphosphate)

  Energy ‘currency’ in every living cell

  Nucleotide used in cell as coenzyme
• Function of ATP


  Transports chemical energy within cells for metabolism