C. Protein Channels- embedded proteins that are specific to certain atoms or molecules. Na+, Cl-, Ca2+. Many are "gated"

D. Endocytosis- Active movement of chemicals into the cell by:
      1. Phagocytosis- (Amoeba) When the cell envelops the solid materials, encloses it in a vacuole and digests it.
     2. Pinocytosis- Same as #1, but material engulfed is liquid.

E. Facillitated Diffusion- Passive movement of longer chemicals by bonding to a receptor protein on membrane surface and than the membrane folds around it.

F. Exocytosis- Active transport of chemicals out of the cell: usually membrane bound by the Golgi Apparatus.

G. Na+/K+ Pump (sodium/potassium pump)- Active transport of Na+ out of the cell and K+ into the cell.