GLUCOSE OXIDATION EQUATION
Glucose + 6 O2 –> 6 CO2 + 6 H2O + Energy (ATP + heat)

• Most energy is generated in mitochondrial matrix

Common Abbreviations:

• ATP: adenosine triphosphate
• NADH: nicotinamide adenine dinucleotide
• FADH2: flavin adenine dinucleotide
• CoA: Coenzyme A

KEY PROCESSES IN GLUCOSE OXIDATION

• Glycolysis
• Pyruvate decarboxylation
• Citric acid cycle (also known as the Krebs’ cycle and the tri-carboxylic acid (TCA) cycle)
• Oxidative phosphorylation (electron transport chain & chemiosmosis)

CITRIC ACID CYCLE

• 1 glucose molecule requires 2 citric acid cycle turns
• Input for each turn: 1 Acetyl CoA
• Output for each turn: 3 NADH + 2 CO2 + 1 ATP + 1 FADH2
• NADH & FADH2: electron transfer molecules for oxidative phosphorylation
• Occurs in mitochondrial matrix

Substrate level phosphorylation

• ATP generated from substrates in glycolysis and citric acid cycle
• NOT from oxidative phosphorylation via NADH or FADH2

OXIDATIVE PHOSPHORYLATION

• Input: 10 NADH + 2 FADH2 (from glycolysis, pyruvate decarboxylation & CAC)
• Generates 30-34 molecules of ATP per glucose
• Main energy-generating process in respiration
• Comprises electron transport chain and chemiosmosis
• Occurs on inner mitochondrial membrane

Electron transport chain

• Series of redox reactions
• Pumps proton from matrix into intermembrane space
• Generates electrochemical gradient for ATP synthesis via ATP synthase
• Contains several protein complexes (I through IV)
• NADH gives electrons to complex I
• FADH2 gives electrons to complex II
• Complex I, III, and IV pump H+ into intermembrane space (Complex II DOES NOT)
• Complex IV consumes 1 O2 (final e- acceptor) to produce 2 H2O

Chemiosmosis

• ATP synthase: harnesses energy in electrochemical gradient (generated by ETC) to synthesize ATP from ADP & Pi