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Volume I · MMXXVI AP Biology
Library› AP Biology› Unit 1: Chemistry of Life
⁂   AP Biology · Unit 1

1. Chemistry of Life

8–11% of the AP exam. 7 key topics. 4 common errors analyzed.

8–11% exam weight 6 instructional periods

Unit 1: Chemistry of Life

Unit 1 covers chemistry of life — a core component of the AP Biology curriculum. Master these concepts to build the mechanistic vocabulary the FRQ rubrics demand.

Key topics in this unit

  1. Elements essential for carbon-based life
  2. Properties of water: cohesion, adhesion, specific heat, polarity, hydrogen bonding
  3. Biological macromolecules: carbohydrates, lipids, proteins, nucleic acids — structure and function
  4. Enzyme structure: active site, substrate specificity, activation energy
  5. Factors affecting enzyme activity: temperature, pH, substrate concentration, inhibitors
  6. Free energy and thermodynamics: Gibbs free energy (ΔG), endergonic vs. exergonic reactions
  7. ATP as biological energy currency

Common errors — what the rubric penalizes

These are the most frequently penalized mistakes on AP exam FRQs and MCQs. Review each before your next practice session.

Common error

Confusing dehydration synthesis with hydrolysis when describing macromolecule assembly and breakdown

Common error

Stating that enzymes change the free energy of a reaction rather than lowering the activation energy barrier

Common error

Misidentifying competitive vs. noncompetitive inhibition effects on Km and Vmax from a Michaelis-Menten graph

Common error

Treating ΔG = ΔH − TΔS as a memorized formula without connecting the sign of ΔG to reaction spontaneity

Study checklist

  • Can you list all key topics from memory without this page?
  • Have you worked through at least one FRQ-style question per topic?
  • Can you explain each common error above — and why the correct answer differs?
  • Have you reviewed the relevant College Board CED section and formula sheet entries?
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Our worked solutions and practice questions are original instructional content created by Tian2 AP. They are aligned to the concepts and skills described in College Board’s Course and Exam Description and are not reproductions of, or affiliated with, College Board’s official materials.