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Bio102: Introduction to Cell Biology and Genetics
Aerobic Respiration
Key Terms:
Metabolic pathway
ATP, ADP
Carbohydrates
Oxidation Reaction
Reduction Reaction
Glycolysis
Citric Acid Cycle
Electron Transport
Oxidative Phosphorylation
Co-enzyme
NAD+ and NADH
FAD and FADH2
Pyruvate
Acetyl-CoA
ATP Synthase
Key Concepts:
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Metabolism is a series of energy transfers.
Follow the movement of Energy through different molecules.
Follow the movement of Carbon atoms.
Lecture Outline:
Metabolic pathway = sequence of enzyme-catalyzed reactions that accomplish a specific purpose
oxidation and reduction reactions
other short-term energy storage molecules include NADH and FADH2
Overview of Aerobic Respiration:
1. Glycolysis
glucose  pyruvate
2. Citric Acid Cycle
pyruvate  CO2 and reduced coenzymes
3. Electron Transport
red. coenzymes are re-ox.; e- passed to O2; H+ gradient
4. Chemiosmosis
H+ gradient drives ATP synthesis
Glycolysis is universal, anaerobic and cytosolic
2 ATP in; 4 ATP out & 2 reduced coenzymes
glucose (six carbons, C6)  2 moleucles of pyruvate (three carbons, C3)
Citric Acid Cycle, in the mitochondria
Pyruvate crosses into mitochondrial matrix and is converted to acetyl-CoA in a Transition Step
Metabolic pathway that is arranged as a cycle
entry of a C2 to change a C4 to a C6
two oxidative decarboxylations (CO2 released each time)
four oxidations (three with NAD+, one with FAD)
one 'direct' generation of ATP (via GTP)
Electron Transport
Purpose is to generate a proton (H+) gradient and re-oxidize the reduced coenzymes
inner mitochondrial membrane (or the plasma membrane in prokaryotes)
energy is released as electrons are passed, some of that energy is captured
protons are pumped across the membrane, from inside to outside
proton gradient has been created: high concentration of protons outside, low inside
this is an effective form of storing energy
Chemiosmosis
harvest energy out of proton gradient and make (lots) of ATP
enzyme is ATP Synthase
yield: 3 ATP per NADH or 2 ATP per FADH2
Oxidative Phosphorylation = Electron Transport + Chemiosmosis