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Cellular Respiration Pre-lecture
Know the following parts of a mitochondria
Intermembrane space
Cristae – folds in the inner membrane
Matrix – interior most region
The stages of Cellular Respiration
The 4 stages of cellular respiration:
1. Glycolysis (glucose  2 pyruvate)
• Occurs in the cytosol
2. Pyruvate oxidation (pyruvate acetyl CoA) This stage is
often included as part of the citric acid cycle
• Occurs in the mitochondrial matrix
3. The citric acid cycle (completes the breakdown of glucose)
• Occurs in the mitochondrial matrix
4. Oxidative phosphorylation (accounts for most of the ATP
synthesis)
• Occurs in the innermembrane / cristae
Cell respiration Overall Reaction
Glycolysis : Energy investment phase
Investment Phase
4 ADP & 2 NAD+
2 ATP
Glucose
Payoff phase
2 G3P
2 ADP
2Pyruvate
4 ATP
2 NADH + H+
• Aerobic respiration consumes organic molecules and O2 and
yields ATP
• Fermentation is a partial degradation of sugars that occurs
without O2
• Anaerobic respiration is similar to aerobic respiration but
consumes compounds other than O2
Redox Reactions: Oxidation & Reduction
Chemical reactions that transfer electrons
Oxidation - substance loses electrons (is oxidized)
Reduction - substance gains electrons, (is reduced) (the
amount of positive charge is reduced)
•The electron donor is called the reducing agent
•The electron receptor is called the oxidizing agent