Enzymes lower activation energy; they do not change ΔG or equilibrium.
Common trap: A catalyst does not make an energetically unfavorable reaction favorable.
UNIT 03 / REVIEW
Cellular Energetics
Energy cannot be created. Your excuses apparently can.
Active recall activities40 original questions · 6 topics
Glucose→
NADH / FADH₂→
H⁺ gradient→
ATP
Energy transfers through carriers and gradients. It does not magically appear in ATP.
ATP hydrolysis can power cellular work through coupling.
Common trap: Breaking a bond requires energy. ATP hydrolysis releases net energy because of the full reaction.
Glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation transfer energy.
Common trap: Plants respire too. Photosynthesis does not replace cellular respiration.
A proton gradient powers ATP synthase across an intact membrane.
Common trap: Electrons do not flow through ATP synthase. Protons do.
Light reactions make ATP and NADPH; the Calvin cycle reduces carbon.
Common trap: The Calvin cycle does not run indefinitely in darkness: it needs light-reaction products.
Separate the manipulated variable, measured response, controls, and uncertainty.
Common trap: A plateau is not evidence that an enzyme has stopped: a constant maximum rate still makes product.
Keep going
Original review notes informed by standard biology principles. Check the official AP Biology framework ↗ and OpenStax Biology 2e ↗ for further reading.