Give two functions of membranes at the cell surface and two functions of membranes within cells.

At the cell surface membranes play a key role in regulating the enterance and exit of molecules, they alos play an important role in forming a vesicle during pinocytosis.

Within the cell the cell membrane will be involved in lysosome formation (lysosomes contain hydrolytic enzymes which degrade compounds). Secondly, cell membranes within the cell form a nucleur envolope which will form the nucleus and protect the DNA.