Chemical Pathways

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

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

Steps of Cellular Respiration Glycolysis Kreb Cycle Electron Transport Chain

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

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

Alcoholic Fermentation CO2 and alcohol as wastes yeast

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