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AP Biology

Comprehensive AP Biology guide covering all eight units — Chemistry of Life, Cell Structure & Function, Cellular Energetics, Cell Communication & Cell Cycle, Heredity, Gene Expression & Regulation, Natural Selection, and Ecology. Built for the 5.

Topics Covered

Chemistry of Life
Cell Structure
Cellular Energetics
Cell Communication & Cycle
Heredity
Gene Expression
Natural Selection
Ecology

What you get

Full topic-by-topic curriculum coverage
Spaced-repetition flashcards for every topic
Multiple-choice quizzes with explanations
Term-matching vocabulary games
Aligned with the College Board CED
Exam technique tips throughout
Key terms & definitions bank
12 months of access from purchase
Free Sample

Unit 1 — Chemistry of Life

THE BIG PICTURE. Unit 1 establishes the chemical foundation of life — and the structure-function relationship that the rest of AP Biology builds on. The unit weighs 8–11% of the AP exam and connects to Big Idea 2 (Energetics), Big Idea 3 (Information Storage and Transmission), and Big Idea 4 (Systems Interactions). Mastery of monomer-polymer relationships, water chemistry, and protein folding is essential — every later unit assumes this foundation.

Sample Flashcards

Why is water a polar molecule, and why does that matter biologically?

Oxygen is far more electronegative than hydrogen, pulling shared electrons closer. The O end is δ−; the H ends are δ+. This polarity allows water to form H-bonds with other water molecules and with polar/ionic solutes — giving it cohesion, adhesion, high specific heat, high heat of vaporization, and the ability to diss…

List four properties of water and one biological consequence of each.

1) High specific heat → buffers temperature in oceans/cells. 2) High heat of vaporization → evaporative cooling (sweat). 3) Cohesion + tension → unbroken water column in xylem. 4) Less dense as a solid → ice floats, insulating water beneath in winter.

Sample Key Terms

Polarity

Unequal sharing of electrons in a covalent bond, producing partial positive and partial negative regions on a molecule. Drives water's hydrogen bonding.

Hydrogen Bond

A weak attraction between a partially positive H atom (bonded to N, O, or F) and a lone pair on another electronegative atom. Individually weak, collectively powerful.

Cohesion

Water molecules sticking to other water molecules via H-bonds. Enables surface tension and the unbroken column of water in plant xylem.

What's Covered

  • Unit 1 — Chemistry of Life
  • Unit 2 — Cell Structure & Function
  • Unit 3 — Cellular Energetics
  • Unit 4 — Cell Communication & Cell Cycle
  • Unit 5 — Heredity
  • Unit 6 — Gene Expression & Regulation
  • Unit 7 — Natural Selection & Evolution
  • Unit 8 — Ecology
  • AP Biology — Skills, Labs & Exam Strategy

9 topics · 176+ flashcards · quizzes & matching games included

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AP Biology Study Guide | Prep Den