Cellular Respiration
How organisms make ATP
Cellular Respiration • The process that produces energy
(ATP) by breaking down food molecules
6O2 + C6H12O6 6CO2 + 6H2O
Glycolysis: the first step in respiration
• Happens in the cytoplasm• Glucose is split into 2 molecules of
pyruvic acid• Results in the net production of 2
ATP
Two Types of RespirationAerobic
• Occurs in the presence of oxygen
• Occurs in the mitochondria
• Krebs cycle – pyruvic acid is broken down into carbon dioxide in a series of energy producing steps (electron transport chain)
• Net ATP production: 34 ATP (per glucose molecule) + 2 ATP (glycolysis) = 36 ATP
Anaerobic• Fermentation – occurs
in the absence of oxygen. Two types:• alcohol fermentation • lactic acid fermentation
• Occurs in the cytoplasm
• Net ATP production: 2 ATP per glucose molecule
Two Pathways to ATPAerobic
1. Glycolysis = 2 ATP2. O2 present =3. Pyruvic acid
enters the mitochondria
4. 34 ATP produced5. Net ATP = 36
Anaerobic1. Glycolysis = 2 ATP2. No O2 present = 3. Lactic acid or
alcohol fermentation
4. No additional ATP produced
5. Net ATP = 2
Mitochondria Drawing• Copy, color, and glue in the
MITOCHONDRIA, figure 4.2 on page 108.
• I’ll check off next class for 10 points.