Passive transport across the plasma membrane can occur through simple diffusion of molecules like water, or through transport proteins. Transport proteins include channel proteins that form channels for molecules to pass through simultaneously without energy input, and carrier proteins that bind molecules and change shape to transport them one by one against the concentration gradient through facilitated diffusion, requiring no energy from the cell. All of these examples of passive transport rely on molecular movement down a concentration gradient without cellular energy input.

1. Passive Transport Ch 8

2. Some molecules like water can pass through the plasma membrane by simple diffusion

3. If the cells uses NO_______ to move the particles, the movement across the membrane is called __________________ ENERGY PASSIVE TRANSPORT

4. Passive transport of material across a membrane using transport proteins is called _______________ Facilitated Diffusion

7. Some proteins are _______ proteins. This allows movement with the concentration gradient and requires NO ENERGY from the cell. Channel

8. Channel Protein

10. Some proteins are _______ proteins. They have a very specific shape and allow only one molecule (or group of closely related molecules) to pass through. Carrier

11. Carrier Protein Step one Step two

12. Channel Carrier

13. One molecule in one direction More than one molecule together Move molecules simultaneously in opposite directions

14. All of these are examples of PASSIVE TRANSPORT and require NO ENERGY FROM THE CELL Diffusion implies that the molecules are all moving with (down) the concentration gradient