AP Biology Unit 4: Cell Communication (4.1) Lesson GuideGive your students a crystal-clear understanding of one of the most tested AP Biology topics: cell communication. This visually rich, no-prep resource breaks down signaling pathways with simple explanations, high-quality graphics, and AP-style practice questions. β¨ Whatβs Included Cover page + disclaimer Overview of cell communication (growth, stress, infections, hormones) Direct vs. Chemical Signaling Juxtacrine, paracrine, autocrine,