, Why do cells need membranes?
To compartmentalise- separate the cells components from its
external environment. The formation of separate membrane-
bound areas in a cell is called compartmentalisation which is
vital to a cell as metabolism includes many incompatible
reactions.
Control entry and exit of substances
Communication with the external environment- contains
receptors for chemical signals to other cells (hormones & drugs
may bind to membrane bound receptors)
Site of chemical reactions
Allows cell to change shape
Transport and packaging within a cell (vesicles)
Recognition as self/non self- has antigens so that the immune
system can recognise the cell as being ‘self’ and not attack it
Bind cells within a tissue
May contain enzymes involved in specific metabolic pathways
, phospholipid
Phosphate heads face
aqueous solution
Hydrophobic tails face
inwards
The phospholipid bilayer is
about 7nm in width
To compartmentalise- separate the cells components from its
external environment. The formation of separate membrane-
bound areas in a cell is called compartmentalisation which is
vital to a cell as metabolism includes many incompatible
reactions.
Control entry and exit of substances
Communication with the external environment- contains
receptors for chemical signals to other cells (hormones & drugs
may bind to membrane bound receptors)
Site of chemical reactions
Allows cell to change shape
Transport and packaging within a cell (vesicles)
Recognition as self/non self- has antigens so that the immune
system can recognise the cell as being ‘self’ and not attack it
Bind cells within a tissue
May contain enzymes involved in specific metabolic pathways
, phospholipid
Phosphate heads face
aqueous solution
Hydrophobic tails face
inwards
The phospholipid bilayer is
about 7nm in width
