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

http://www.sumanasinc.com/webcontent/animations/content/cellularrespiration.html

Cellular RespirationStage 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-

Tran

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tPyruvic Acid

Cellular RespirationStage 2: Krebs Cycle

•Takes place in mitochondrial matrix.•Pyruvic Acid molecules lose molecules of CO2 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 FADH2

Cellular RespirationStage 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 O2 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 O2.–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.–CO2 released by yeast causes bread dough

to rise.