Cellular Diffusion All cells have an outer protective casing, the cell membrane. It protects the cell from the outside world, but is also vital in the transfer of particles in and out of the cell. The cell membrane controls which particles can enter, and which particles can not, because it is selectively permeable. The membrane is made up of a bi-layer of lipid molecules, which have very small spaces between each other, and if a particle is small enough to fit in-between these gaps, then it can pass through the membrane. There are also proteins in the m....

Words In Essay: 611 Approximate Pages: 3

You are just minutes away from instant access to viewing this paper along with over 35,000 other essays and term papers. What are you waiting for? That paper isn't going to write itself. Join today and get a ton of help with that paper! Membership Options Price Recurring 1 month  subscription $17.95 Y 3 months subscription $34.95 Y 6 months subscription $59.95 N