1. Anaerobic Respiration and Alternative Pathways for fuel

2. 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 + 6O  6H2O + 6CO2

3. 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

4. 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.

5. Picture of Pathway Glycolysis Lots of Oxygen Not enough Oxygen
Cellular Respiration
Alcoholic Fermentation
Lactic Acid Fermentation

6. Cellular Respiration Oxygen is required
Takes place in the mitochondria
Produces ATP and releases CO2 and H2O as byproducts
Muscles will do this as long as they don’t run out of oxygen

7. Lactic Acid Fermentation
Takes place when there’s 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

8. 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 this—we use them to make beer, wine, and bread.

9. 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 fermentation—it would kill your cells

10. Related Pathways to Energy Production

11. 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 cell’s proteins
amino groups removed in deamination and converted into ammonia (wastes)
rest of a.a. continue through glycolysis or Kreb’s cycle (depending on composition)

12. 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 β-oxidation – 2 carbons at a time are chopped off into acetyl groups which combine with co-enzyme A to produce acteyl-coA (used in Kreb’s 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