PUMP, CARRIER AND CHENNELS
§ MEMBRANE TRANSPORT:
§ Cell exchanges both
matters and energy between themselves and the environment through the plasma
membrane.
§In this transport molecules are entered into the cell
and metabolic waste expelled via plasma membrane & this traffic meticulosly regulate.
§ plasma
membrane is impermeable and it prevents water soluble substances from escaping
the cell.
§Plasma membrane has evolved a vectorial
transport mechanism
to bring in them and out the waste
Ø Molecules can diffuse
across the membrane down the concentration gradient , but the rate
of diffusion will be depends upons
the size of the molecules , types of charges it bears and degree of lipids
solubility.
Ø Permeability of
uncharged molecules is very slow. For eg:
sugars , amino acids , nucleotides, glucose etc.
Ø these are
transported via MTP mechanism[ Membrane transport
protein mechanism].
Ø MTP mechanism is
specific for a specific substances called UNIPORT .
Ø Some MTP mechanism
two molecular species simultaneously in same direction so its called SYMPORT,
and if in opposite
direction called ANTIPORT……
§ Tranport proteins are called COPORT.
§Membrane protein transfer the molecules by making an aqueous channel called channel protein.
some molecules are passing through the membrane by attaching with the protein molecule are called , carrier proteins.
§ Tranport proteins are called COPORT.
§Membrane protein transfer the molecules by making an aqueous channel called channel protein.
some molecules are passing through the membrane by attaching with the protein molecule are called , carrier proteins.
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