Cellular Respiration

Redox Reactions

Transfer of electrons

Oxidation

Loss of electrons

Reduction

Gain of electrons

Glucose is…

Oxidized to CO₂

Oxygen is…

Reduced to H₂O

Formula for Cellular Respiration

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Substrate-level phosphorylation

reactions that directly phosphorylate ADP to ATP

Dehydrogenation

Redox reaction; transfer of hydrogens to NAD+ or FAD

Decarboxylation

Carboxyl group removed and CO₂ released

Preparation reactions

molecules rearrange to prepare for reactions 

Where does glycolysis occur?

Cytosol 

Glycolysis breaks down a six carbon glucose molecule into…

2 three carbon molecules (pyruvate)

Glycolysis Products

2 ATP (net)

2 Pyruvate

2 NADH + 2H⁺

Glycolysis Reactants 

2 ATP (Energy Investment) 

4 ADP + 4P (Energy Payoff)

2 NAD⁺ + 4 e^- + 4 H⁺  (Energy Payoff) 

Aerobic Respiration

requires oxygen; cellular respiration

Anaerobic Respiration

Does not use oxygen

Fermentation

inefficient process used when other pathways cannot be used 

Location of pyruvate oxidation (Acetyl-CoA)

Mitochondrial Matrix

Pyruvate Oxidation Reactants

2 Pyruvate

NAD⁺

Coenzyme A (CoA)

Pyruvate Oxidation Products 

2 Acetyl CoA

CO₂ 

2 NADH 

Location of Citric Acid Cycle

Mitochondrial Matrix

Beginning of Krebs Cycle

Acetyl CoA (2 carbon) + Oxaloacetate (4 carbon) = Citric Acid (6 carbon)

Products of Citric Acid Cycle 

2 CO₂ (waste product) 

3 NADH (goes to ETC) 

1 FADH₂ (goes to ETC) 

1 ATP (GTP) (direct energy currency for cell) 

Location of the ETC

Inner mitochondrial membrane

Oxidative Phosphorylation

• Primary way for producing ATP

• Uses energy from electron carriers (NADH and FADH₂) to power ATP Synthase

• Oxygen acts as final electron acceptor making water

Chemiosmosis 

• process of moving ions (H⁺) across a semi permeable membrane and down electrochemical gradient 

• Uses energy from proton gradient to drive ATP production

• Protons move through protein channel ATP Synthase 

Phosphofructokinase

• enzyme for one of the earliest steps in glycolysis

• highly regulated in animals