Sophia Learning
Sophia: Facilitated Diffusion
A video presentation describing how transport proteins in the cell membrane allow solutes to cross the cell membrane without the use of cellular energy. [5:41]
Khan Academy
Khan Academy: Energy and Transport: Concentration Gradients
A concentration gradient occurs when the concentration of particles is higher in one area than another. In passive transport, particles will diffuse down a concentration gradient, from areas of higher concentration to areas of lower...
Khan Academy
Khan Academy: Uniporters, Symporters and Antiporters
Uniporters, symporters, and antiporters are proteins that are used in the transport of substances across a cell membrane. This video describes how each of these works in the transport process. [7:13]
Sophia Learning
Sophia: Diffusion: Lesson 3
This lesson explains the process of diffusion. It explains how diffusion is a passive form of transport, used to move molecules down their concentration gradient. It is 3 of 8 in the series titled "Diffusion."
Sophia Learning
Sophia: Osmosis: Lesson 3
This lesson explains the process of osmosis. It explains how osmosis is a passive form of transport, used to move water molecules across a semi-permeable membrane, down their concentration gradient. It is 3 of 8 in the series titled...
Bozeman Science
Bozeman Science: Transport Across Cell Membranes
Paul Andersen describes how cells move materials across the cell membrane. All movement can be classified as passive or active. Passive transport, like diffusion, requires no energy as particles move along their gradient. Active...