Cell membranes and transport

Diffusion= Movement of molecules from a region of high to low concentration. It is a passive process. Determinants:

1. Steepness of the concentration gradient 
2. Temperature
3. Surface Area
4. Distance/Thickness of membrane
5. Size of molecule 

Facilitated diffusion= Diffusion with the help of protein molecules (transports water and glucose

Osmosis= The net movement of water from a region of high to low water potential through a partially permeable membrane. (Pure water has a water potential of 0 any addition of solute lowers)

Active transport= Uses ATP to move substances against their concentration gradient, (conducted by carrier proteins)

Endocytosis= A section of the plasma membrane surrounds a large object and then "pinches" off to form a vesicle (Bulk transfer of materials into the cell)

Exocytosis= Transported substances are carried in vesicles to the cell membrane where they are released after fusion with the plasma membrane

The effect of water potential on cells

Animal:

Plant: