Functions of proteins in the cell membrane
15:13:00
Channel: allows specific substance to move through water-filled pore. Most plasma
membranes include specific channels for several common ions.
Transporter: transports specific substances across membrane by changing shape. For
example: amino acids, needed to synthesize new proteins, enter cells via
transporters.
Receptor: recognizes specific ligand and alters cell’s function in some way. For
example, antidiuretic hormone binds to receptors in the kidneys and changes the
water permeability of certain plasma membranes.
Enzyme: catalyzes reaction inside or outside cell (depending on which
direction the active site faces). For example, lactase protruding from epithelial
cells lining your small intestine splits the disaccharide lactose in the milk
your drink.
Cell
Identity Marker: distinguisher your cells from
anyone else’s (unless you are an identical twin). An important class of such
markers are the major histocampatability (MHC) proteins.
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