1. Chemical Pathways

2. Chemical Energy & Food How much energy is present in food?
one gram of sugar glucose releases 3811 calories of heat energy when burned
calorie: amount of energy needed to raise the temperature of 1 gram of water 1 ºC
Calorie (food labels) = 1000 calories

4. Cellular Respiration
process that releases energy by breaking down glucose in the presence of oxygen
6O2 + C6H12O6  6CO2 + 6H2O + Energy

5. Steps of Cellular Respiration
Glycolysis
Kreb Cycle
Electron Transport Chain

6. Glycolysis Occurs in the cytoplasm doesn’t require oxygen
1 molecule of glucose is broken in ½  2 pyruvic acid
ATP Production: 2 ATP used in glycolysis
4 ATP molecules are produced
Net Gain: 2 ATP molecules
NADH Production
NAD+ - electron carrier
4 high-energy electrons: NAD+  NADH

9. Fermentation w/no O2: glycolysis is followed by fermentation
Anaerobic: process without oxygen
NADH  NAD+ by moving high energy electrons to pyruvic acid
Allows glycolysis to produce more ATP

10. Alcoholic Fermentation
CO2 and alcohol as wastes
yeast

11. Lactic Acid Fermentation
pyruvic acid from glycolysis  lactic acid
produces by muscles during rapid exercise when your body cannot produce enough oxygen