Complementary Cycles

Food Stores Chemical Energy Chemical Energy is a form of potential energy due to the arrangement of the atoms within the molecules.

Food Stores Chemical Energy

Accessing the Energy in Food Cellular Respiration – a chemical process that uses oxygen to convert the chemical energy in food into ATP.

Accessing the Energy in Food Cellular Respiration - Aerobic Respiration: requires oxygen Anaerobic Respiration: without oxygen (fermentation)

Cellular Respiration Location – Mitochondria

Cellular Respiration – The Big Picture ent/animations/content/cellularrespi ration.html

Cellular Respiration Stage 1: Glycolysis Takes place in cytoplasm “Splitting Sugar” Glucose splits into 2 Pyruvic Acid molecules. 2 Molecules of ATP are spent, but 4 are made. (Net of 2 ATP molecules made) NAD+ picks up e- and brings to ETC. To e- Transport Pyruvic Acid

Cellular Respiration Stage 2: Krebs Cycle Takes place in mitochondrial matrix. Pyruvic Acid molecules lose molecules of CO 2 and becomes a new substance (citric acid). ATP and electron carriers pick up most of the energy. Electron carriers NAD+ and FAD become NADH and FADH 2

Cellular Respiration Stage 3: Electron Transport Chain (ETC) Takes place on inner membrane of mitochondria. Electrons picked up from Glycolysis and Krebs cycle are delivered here. The ETC uses the electrons to change ADP into ATP. Major source of energy!

Anaerobic Respiration Fermentation: When O 2 is not present, NAD+ is used in a different way and continues to make ATP through Glycolysis.

Anaerobic Respiration Lactic Acid Fermentation – Pyruvate in the muscles are converted to Lactate when muscle cells operate without enough O 2. – Fermentation enables glycolysis to produce ATP as long as glucose lasts. – Lactic Acid build up can cause sore muscles.

Anaerobic Respiration Alcoholic Fermentation – In other organisms (ex. Yeast, fungus) pyruvate is broken down to ethanol (ethyl alcohol). – Glycolysis continues to make ATP. – Used in the preparation of many foods and beverages. – CO 2 released by yeast causes bread dough to rise.