Unit 3 · 3.5 — Cellular Respiration [cite: 9, 10, 28]

Everything to learn here

• Concept: Cellular respiration systematically extracts chemical potential energy from biological macromolecules to synthesize massive amounts of ATP [cite: 13].
• Concept: Glycolysis occurs in the cytoplasm, breaking glucose into two pyruvate molecules and generating a net yield of 2 ATP via an anaerobic pathway [cite: 14].
• Concept: The Krebs Cycle (Citric Acid Cycle) occurs deep in the mitochondrial matrix, fully oxidizing acetyl-CoA to $CO_2$ and generating electron-carrying NADH and $FADH_2$ [cite: 14, 37].
• Concept: The Electron Transport Chain (ETC) extracts electrons from NADH and $FADH_2$ to pump protons into the intermembrane space, building a massive electrochemical proton gradient [cite: 13].
• Concept: Fermentation allows glycolysis to proceed continuously in the complete absence of oxygen by rapidly regenerating $NAD^+$ (producing either lactic acid or ethanol) [cite: 13, 14].
• Equation: Equation/Process: Aerobic cellular respiration yields approximately 36–38 ATP per glucose molecule; strictly anaerobic fermentation yields only 2 ATP [cite: 31].
• Vocabulary: Chemiosmosis — the physical flow of protons down their electrochemical gradient through the enzyme ATP synthase, mechanically driving the phosphorylation of ADP to ATP [cite: 14, 38].
• Vocabulary: Oxidative Phosphorylation — the massive ATP-generating process comprising both the Electron Transport Chain and chemiosmosis [cite: 13, 14].
• Lab: Lab Skill: AP Biology Required Investigation — Cellular Respiration: Interpret experimental respirometer data to accurately calculate $O_2$ consumption rates over time for germinating seeds or small animals [cite: 6, 35, 39].
• Concept: Mitochondrial features enable eukaryotes to extract energy from macromolecules to synthesize ATP.
• Concept: Metabolic pathways like respiration and fermentation allow cells to harvest energy from organic compounds.
• Concept: Aerobic respiration involves coordinated enzymatic reactions that capture energy from biological macromolecules.
• Concept: Electrons from NADH and FADH2 move through a chain to oxygen, creating a proton gradient.
• Concept: Pyruvate oxidation and the Krebs cycle release electrons to reduce NAD+ and FAD into high-energy carriers.
• Concept: The Krebs cycle in the mitochondrial matrix releases CO2 and synthesizes ATP from ADP and phosphate.
• Concept: Electron transport creates a proton gradient across the inner mitochondrial membrane, resulting in a pH difference.

Practice problems for this topic are coming — generated and validated by our AI pipeline, aligned to these exact items.