One gram of the sugar glucose when burned in presence of oxygen releases 3811 calories of heat energy. A calorie is the amount of energy needed to raise the temperature 1 gram of water 1 degree Celsius.

1 Kcal = 1000 calories. It gradually release the energy from glucose and other food compounds.

Electron Transport Chain Glycolysis Pathway that releases only a small amount of energy. Krebs Cycle Glycolysis Oxygen Electron Transport Chain Alcoholic No Oxygen Fermentation Lactic

Cellular Respiration Glycolysis + Krebs Cycle Electron Transport Chain _________________________ Cellular Respiration

Cellular Respiration The process that releases energy by breaking down glucose and other food molecules in the presence of oxygen. 6O2+C6H12O6 6CO2 + 6H2O + Energy Oxygen + glucose Carbon dioxide + water + energy

Glycolisis The process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3- carbon compound.

Glycolisis needs 2 ATP to divide Glucose but in return gives 4 ATP. ATP production Glycolisis needs 2 ATP to divide Glucose but in return gives 4 ATP.

NADH Production NAD+ or nicotinamide adenine dinucleotide. It accepts a pair of high- energy electrons. And form NAD+ goes to NADH until transferred to the next molecule.

Glycolysis does not require oxygen Glycolysis does not require oxygen. It can supply energy to cells when oxygen is not available. But when all of the available NAD+ molecules are filled up it cannot keep glycolysis going, and ATP stops.

Fermentation When oxygen is not present it follows another passage. It releases energy from food molecules by producing ATP in the absence of oxygen. Anaerobic – not in air.

Alcoholic Fermentarion Pyruvic acid + NADH alcohol +CO2 + NAD+

Lactic Acid Fermentation Pyruvic acid + NADH Lactic Acid + NAD+