intro

• why is the plasma membrane so selective?
• why must other substances be able to cross organelle membranes?

passive membrane transport

• what is it?
• what drives passive transport?
• why does this happen?
• what does the rate of diffusion depend on?
• what is it called when molecules continue to move after the concentration is the same?
• what factors determine the ease at which a molecule can pass the membrane?

simple diffusion

• what is it?
• what types of molecules can pass?

facilitated diffusion

• what is it?
• why would this happen in contrary to simple diffusion?
• how does it happen?
• channel proteins
• carrier proteins