Anaerobic Respiration and Alternative Pathways for fuel

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Anaerobic Respiration and Alternative Pathways
for fuel
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Cellular Energy

• Animal (and fungi and protist) cells need to
  access the energy stored by photosynthesis.
• They release the energy stored in sugars in a
  process that is the reverse of photosynthesis
• C6H12O6 6O2 --------? 6H2O 6CO2

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Different Pathways after Glycolysis

• There are two main pathways to release energy
  from glucose
• The amount of oxygen available controls the
  pathway
• Plenty of Oxygen Cellular Respiration
• Not much Oxygen Fermentation

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Two types of Fermentation

• Lactic Acid Fermentation Our muscles carry this
  out when they run low on oxygen, producing ATP
  and Lactic Acid
• Alcoholic Fermentation Yeast cells carry this
  out, producing ATP and Alcohol.

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Picture of Pathway

• Glycolysis

Lots of Oxygen
Not enough Oxygen
Cellular Respiration
Alcoholic Fermentation
Lactic Acid Fermentation
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Cellular Respiration

• Oxygen is required
• Takes place in the mitochondria
• Produces 32-34 ATP and releases CO2 and H2O as
  byproducts
• Muscles will do this as long as they dont run
  out of oxygen

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Lactic Acid Fermentation

• Takes place when theres not enough oxygen for
  cellular respiration
• Produces ATP, but also Lactic Acid
• Also regenerates the NAD required to continue
  with glycolysis.
• Muscles do this when they run low on oxygen
• Lactic Acid causes the burning sensation

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Alcoholic Fermentation

• Occurs in organisms that do not carry out
  cellular respiration or lactic acid fermentation
• Produces ATP, but also ethanol and CO2 as
  byproducts.
• Yeast cells do thiswe use them to make beer,
  wine, and bread.

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Our Cells

• Will either do
• Cellular respiration During slow, steady
  exercise
• Lactic Acid Fermentation During strenuous
  exercise like sprinting, or lifting heavy
  weights.
• Do not carry out alcoholic fermentationit would
  kill your cells

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Related Pathways to Energy Production
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• Carbohydrates
• broken into monosaccharide, then broken down for
  energy
• avg. yield of 16 kJ/g of energy
• Proteins
• broken down into amino acids to be used to
  produce cells proteins
• amino groups removed in deamination and converted
  into ammonia (wastes)
• rest of a.a. continue through glycolysis or
  Krebs cycle (depending on composition)

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Lipids

• triglycerides broken into glycerol and fatty
  acids
• glycerol can be converted to glucose (by
  gluconeogenesis) or to DHAP or G3P (which enter
  glycolysis).
• fatty acids go to the matrix of mitochandria and
  undergo ß-oxidation 2 carbons at a time are
  chopped off into acetyl groups which combine with
  co-enzyme A to produce acteyl-coA (used in Krebs
  cycle)
• much more ATP formed than from carbs. ex lauric
  acid (12 C fatty acid) produces 92 ATP
• average yield is 38kJ/g of energy