Cellular Respiration

Process by which cells release energy from molecules of food. Carbohydrates, fats and proteins all contain energy This energy is released gradually in a series of reactions controlled by enzymes. Release energy is stored as ATP for later use. ATP is the currency of the cell.

The Chemical Equation C 6 H 12 O CO 2 + 6H 2 O + 38 ATP Glucose + Oxygen Carbon Dioxide + Water + Stored Energy 2 ATP are used to make this process take place Net Gain = 36 ATP for 1 molecule of Glucose

4 Main Steps in Respiration Glycolysis Intermediate Reaction Krebs Citric Acid Cycle Electron Transport System

Glycolysis 2 ATP are used to start the process Glucose is split into 2 3-carbon pyruvic acid molecules Some Hydrogen is released 4 ATP are made, a net gain of 2 ATP It occurs in virtually all cells. In eukaryotes, it occurs in the cytosol.cytosol

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Intermediate Reaction Takes place in the mitochondria (powerhouse of the cell) Breakdown of the 2 3-carbon pyruvic acid molecules 2 carbon fragments, acetic acid are formed and 2 CO 2 and more hydrogen are released Acetic Acid is carried by Acetyl CoA to Kreb Cycle

Krebs Citric Acid Cycle Breakdown Continues Four more CO2 are released Many more Hydrogen are released and picked up by NAD+ to form NADH Two more ATP are made

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Electron Transport System Hydrogen atoms are transferred to bond with oxygen atoms to make water 32 ATP are made e - power e - carriers Water wheel Net Result 36 ATP produced

Oxygen is vital! It is the final acceptor of electrons – without it the process stops. Pyruvic acid is converted to lactic acid, which accumulates in muscles causing fatigue and soreness.

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