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AP Biology Units

All eight units of the AP Biology course framework, with approximate exam weighting and what each covers. The course runs from the chemistry of life through cell structure, cellular energetics, cell communication, heredity, gene expression, natural selection, and ecology. Units 3, 6, and 7 tend to carry the heaviest weighting, so budget your study time toward them. Approximate weightings are from the College Board Course and Exam Description (see also the formula sheet); exact weightings vary year to year.

1

Chemistry of Life

~8-11% of exam

The properties of water and the biological macromolecules, carbohydrates, lipids, proteins, and nucleic acids, and how molecular structure gives rise to function.

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2

Cell Structure and Function

~10-13% of exam

Organelles, membrane structure and transport (osmosis, diffusion, active transport), cell size and surface-area-to-volume, compartmentalization, and the origin of cells.

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3

Cellular Energetics

~12-16% of exam

Enzymes, cellular respiration, photosynthesis, energy flow through living systems, and molecular stability. One of the most heavily weighted units.

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4

Cell Communication and Cell Cycle

~10-15% of exam

Signal transduction, feedback mechanisms, the cell cycle and its regulation, and mitosis.

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5

Heredity

~8-11% of exam

Meiosis, Mendelian genetics, patterns of inheritance, chromosomal inheritance, and environmental effects on phenotype.

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6

Gene Expression and Regulation

~12-16% of exam

DNA and RNA structure and replication, transcription and translation, gene regulation, mutations, and biotechnology. One of the most heavily weighted units.

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7

Natural Selection

~13-20% of exam

Evidence for evolution, natural selection, population genetics and Hardy-Weinberg, speciation, phylogeny, and the origin of life. The heaviest unit on the exam.

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8

Ecology

~10-15% of exam

Communication and behavior, energy flow, population ecology, community and ecosystem dynamics, biodiversity, and disruptions to ecosystems.

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1–8

The whole course.

480 challenge problems · 60-question mock exam · all-units arcade

Everything above, mixed together. Work the whole-course challenge deck, sit an exam-length cumulative whose 60 questions mirror the real section's unit weighting, or blast every unit's misconceptions in the arcade.

Weightings above are the College Board's approximate multiple-choice ranges and shift slightly year to year. For more on the test itself, see the exam overview, free-response guide, practice questions, formula sheet, score calculator, and is it hard?