Khan Academy Static

2A: Not all shall pass! Yards have fences, and cells have membranes. You don’t want just anybody waltzing into your backyard. Similarly, a healthy cell doesn’t just let in any random molecule - this is the concept of selective permeability. Some molecules (e.g. steroids) more easily cross the barrier whereas others (e.g. charged ions) have a more difficult time getting inside the cell without a little help from transporters in the membrane.

14891_Phospholipid_structure.html

14890_Cell_membrane_introduction.html

14892_Cell_membrane_overview_and_fluid_mosaic_model.html

14893_Cell_membrane_proteins.html

14894_Cell_membrane_fluidity.html

14895_Membrane_dynamics.html