Location: The cell membrane is located on the outside layer of a plant and animal cell and protect the cell from its outside enviroments.
Structure: A cell membrane is made from many tiny phospholipids with a hydrophobic tail and a hydrophilic head, so these phospholipids form a bilayer (see picture on the right). There are also some proteins that are shoved in the cell membrane at places.
Function: The main functions of cell membranes are to control the passage of items/fluids in and out of the cell and to protect the cell from the outside enviroment.