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AP Biology Unit 3  ·  Sprint Review  ·  Free

AP Biology Unit 3 — Cellular Energetics

One-page sprint review

Ten pages on enzymes, ATP, redox, photosynthesis, and cellular respiration — the highest-weighted unit on the entire exam.

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Exam Weight
12–16%
MCQs
7–10
FRQ Appearance
Almost Every Year
Sprint Time
~2.5 hours

Quick Glance — all topics in this unit

Priority, exam format, and the trap that most often costs the point. Transcribed from page 1 so this content is searchable.

TopicPriorityFormatKey trap / must-know
3.1 Enzymes★★★MCQ, DataEnzymes lower Ea only — ΔG and equilibrium UNCHANGED.
3.2 Enzyme Regulation★★★MCQ, Data, FRQCompetitive: ↑Km, same Vmax. Noncompetitive: same Km, ↓Vmax.
3.3 ATP & Redox★★★MCQ, FRQOIL RIG; NADH/FADH2 carry electrons to ETC — not ATP.
3.4 Photosynthesis★★★MCQ, FRQ, DataO2 from H2O (NOT CO2); Calvin cycle needs light products.
3.5 Cellular Respiration★★★MCQ, FRQ, Data~90% ATP from ETC (not glycolysis); fermentation = NAD+ regeneration only.

Topic-by-topic visual review

Nine pages, one topic each. Open the PDF for print quality, or scroll to study on screen.

Cover: Unit 3 overview — highest-weighted unit on the exam, FRQ appears almost every year.
Cover  ·  Unit 3 overview — highest-weighted unit on the exam, FRQ appears almost every year.
3.1 Enzymes: Activation energy, induced-fit model, factors affecting enzyme rate, and the ΔG-unchanged trap.
3.1 Enzymes  ·  Activation energy, induced-fit model, factors affecting enzyme rate, and the ΔG-unchanged trap.
3.2 Enzyme Regulation: Competitive vs non-competitive vs allosteric inhibition with Km / Vmax effects.
3.2 Enzyme Regulation  ·  Competitive vs non-competitive vs allosteric inhibition with Km / Vmax effects.
3.3 ATP & Redox: Oxidation = lose electrons (OIL RIG), electron carriers, ATP hydrolysis cycle.
3.3 ATP & Redox  ·  Oxidation = lose electrons (OIL RIG), electron carriers, ATP hydrolysis cycle.
3.4 Photosynthesis Light Reactions: Photosystem II → I, water-splitting source of O2, ATP and NADPH synthesis in the thylakoid.
3.4 Photosynthesis Light Reactions  ·  Photosystem II → I, water-splitting source of O2, ATP and NADPH synthesis in the thylakoid.
3.4 Photosynthesis Calvin Cycle: Carbon fixation by RuBisCO, G3P production, and why the dark reactions need light products.
3.4 Photosynthesis Calvin Cycle  ·  Carbon fixation by RuBisCO, G3P production, and why the dark reactions need light products.
3.5 Cellular Respiration Glycolysis & Krebs: Glucose → pyruvate → acetyl-CoA → CO2, with NADH and FADH2 generation.
3.5 Cellular Respiration Glycolysis & Krebs  ·  Glucose → pyruvate → acetyl-CoA → CO2, with NADH and FADH2 generation.
3.5 Cellular Respiration ETC: Chemiosmosis, the proton gradient, ATP synthase rotation, and where ~90% of ATP actually comes from.
3.5 Cellular Respiration ETC  ·  Chemiosmosis, the proton gradient, ATP synthase rotation, and where ~90% of ATP actually comes from.
3.6 Fermentation: Lactic acid vs ethanol fermentation as NAD+ regeneration, why fermentation is not glycolysis.
3.6 Fermentation  ·  Lactic acid vs ethanol fermentation as NAD+ regeneration, why fermentation is not glycolysis.
Final Review — Traps + Checklist: Top Unit 3 traps and the pre-exam strategy for inhibition graphs and respiration math.
Final Review — Traps + Checklist  ·  Top Unit 3 traps and the pre-exam strategy for inhibition graphs and respiration math.

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