Light energy* Chemical bond energy (ATP*)Energy is stored in the chemical bonds of glucoseATP* hydrolysis ADP + Pi + energy*6CO2 + 12H2O (H source) + energy* glucose*
To synthesize organic molecules, it takes energy and reducing power.ATPSource of attachable H.
To retrieve energy from glucose:1. strip away high energy electrons from the chemical bonds of glucose2. this is oxidation (loss of electrons)3. cellular respiration is a two-step process:remove electronsuse the energy in those electrons
Glycolysisoccurs in the cytoplasm of all living organismsenzymatic splitting of glucoseyields 2 pyruvatesnet gain of 2 ATP and 2 NADH*
Substrate-level phosphorylationNet gain of 2 ATP per glucose
2 electrons removed and carried on NADH x2
Pyruvate oxidized (by NAD+)One C removed as CO2Coenzyme A is addedLeaves acetyl-CoA
Acetyl-CoA can have many fates:ATP synthesis (in mitochondrial matrix)fat synthesislipid synthesisamino acid synthesis
2 CO23 NADH1 FADH21 ATPoriginal 4-C sugar
Electron Transport System
Photosynthesis vs. Cellular Respirationsource of high-energy electronsused electrons cannot be recycled in mitochondria
ATP production decreases when ATP is plentiful.
Animal cells convert pyruvate to lactic acid in the absence of O2Makes NAD+ available so glycolysis can continue
Yeast cells convert pyruvate to ethanol in the absence of O2