You eat food to get energy…..how does this work? By a process called…… Plants make their food, so to get energy from the food they produce they also use a process called …..

1 st step – Glycolysis (using Latin P&S, glycolysis means – loosening of glucose)  The process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid.  Takes place in the cytoplasm  Creates 2 ATP

2 nd step – the Krebs Cycle  Pyruvic acid is broken down in to carbon dioxide in a series of energy extracting reactions.  Creates NADH and FADH 2 (energy carriers, full batteries)  Takes place in the mitochondria  Creates 2 ATP

3 rd step – Electron Transport Chain  Uses the energy stored in NADH and FADH 2 to create ATP  Takes place in the mitochondria  Creates 32 ATP ATP

Big Picture  Glycolysis + the Krebs Cycle + Electron Transport Chain = CELLULAR RESPIRATION  6O 2 + C 6 H 12 O 6  6CO 2 + 6H energy o This equation is the OPPOSITE of photosynthesis

Cellular Respiration only works if you have oxygen (which we breathe in), but sometimes your body can’t get oxygen quickly enough to do cellular respiration … what happens then?

1 st step – Glycolysis  Glycolysis does NOT require oxygen, so the first step is the same.

2 nd step – Alcoholic Fermentation  Yeasts and a few other microorganisms take the two molecules of pyruvic acid produced in glycolysis and convert it to alcohol, carbon dioxide and NAD +  Pyruvic acid + NADH  alcohol + CO 2 + NAD +  Alcoholic fermentation of yeast is what causes bread to rise. When yeast in the dough runs out of oxygen it begins producing carbon dioxide which forms the air spaces you see in a slice of bread. The small amount of alcohol produced in the dough evaporates.

OR 2 nd step – Lactic Acid Fermentation  In many cells, the pyruvic acid from glycolysis is converted to lactic acid.  Pyruvic acid + NADH  Lactic Acid + NAD +  When you exercise vigorously by running, swimming or riding a bike, your large muscles quickly run out of enough oxygen to do cellular respiration. Instead your muscle cells start doing lactic acid fermentation to make ATP (energy). The build up of lactic acid causes a painful burning sensation.  The only way to get rid of this lactic acid is through a process that requires oxygen. This is why you breathe harder after physical activity.