the role of membranes

• Cell membranes separate the internal environment of the cell from the external environment. Cell membranes also separate different areas of cells from each other. This is known as compartmentalisation
• Cell membranes control the exchange of materials passing through them, They are partially permeable.

  Non-polar molecules diffuse through freely

  Large, polar molecules and ions are selectively prevented from passing through the membrane.
• In membranes forming organelles or within organelles, proteins can act as sites of chemical reactions, this links back in to compartmentalisation. These proteins need to be in particular positions for these chemical reactions to occur.
• Cell membranes act as an interface for communication between cells.

  • To control processes in the body
  • To respond to changes in the environment
• cell signalling