This module provides two "skill checks" with questions for students to gauge their general understanding of cellular membrane structure/function and the role membranes play in osmosis and diffusion, as well as the transport of molecules through/across biological membranes. Also contained are five content modules on the following: The Plasma Membrane (introduction) Diffusion and Osmosis Passive Transport Active Transport Bulk Transport Content modules include videos, articles, figures, and illustrations, though the majority are videos. Users/students can also ask questions at the end of each module, and a the community of users have the option to volunteer answers to help clarify understanding or discuss the question further.