1 2 3 4 5 6 7

This is because the solutes bind a layer of water molecules around them, leaving a lower concentration of "free" water.

C. Transport proteins 1. Channels 2. Transporters/pumps

8.13, 8.16, 8.17

Some of the protein "icebergs" allow the transport of large or charged molecules. Some form a hole or channel that allows charged molecules through. These channels can be permanently open, or they can open or close depending on other factors.

Other proteins bind to a molecule on one side of the membrane, then change shape, moving the molecule to the other side

III. Transport8.15 The transport of substances across a membrane can be characterized in several ways depending on whether proteins and/or energy are needed for it to cross. A. Free vs mediated 1. Free = diffusion, not saturable 2. Mediated = assisted, requires proteins, saturable