CK-12 Foundation
Ck 12: Biology: Diffusion
[Free Registration/Login may be required to access all resource tools.] Describes passive transport and diffusion.
BiologyWise
Biology Wise: The Structure and Functions of the Cell Membrane
This resource describes the structure and functions of the cell membrane.
Khan Academy
Khan Academy: Passive Transport & Active Transport Across Cell Membrane Article
The cell membrane is one of the great multi-taskers of biology. It provides structure for the cell, protects cytosolic contents from the environment, and allows cells to act as specialized units. Learn how the membrane functions to...
Kenyon College
Kenyon College: Passive Transport Versus Active Transport
A brief but clear explanation of passive and active transport. Examples are provided to further enhance clarity of the concepts.