cellular respiration - oxidation of organic molecules, release of energy

• C6H12O6 + 6O2 >> 6 CO2 + 6H2O + ATP + heat
• usually organic molecules taken in, CO2/H2O released as waste
• adenosine triphosphate (ATP) - used as direct source of energy in cellular metabolism
• glycolysis - oxidation of glucose to pyruvate
  • some energy stored in ATP
  • occurs w/ or w/o oxygen, but doesn't continue to citric acid cycle w/o oxygen
• citric acid cycle (tricarboxylic acid cycle or Krebs cycle)
  • oxidizes pyruvate to CO2
  • must use oxygen
  • used by aerobes
  • stores energy in nicotinamide adenine dinucleotide (NAD)
• electron transport chain - makes proton gradients from energy in NAD
  • makes about 18x as much ATP as glycolysis
  • oxygen - final electron acceptor; chain won't work w/o oxygen
  • measuring O2 consumption/ CO2 production also measures the aerobic respiration rate

anaerobes - live w/o oxygen; may even be poisoned by oxygen

• use inorganic electron acceptors
• uses fermentation instead of Krebs cycle to reduce pyruvate
  • makes ethanol in plants/yeast
  • makes lactic acid in animals
• C6H12O6>> 2C2H5OH (ethanol) + 2CO2 + ATP + heat
• C6H12O6>> 2CH3CHOHCOOH + ATP + heat
• produces 18 fewer ATP than aerobic respiration
• pickling - preserves food, involves anaerobic fermentation of sugars to lactic acid
• wine making - invovles alcoholic fermentation by yeasts