BIOL150 Chapter Notes - Chapter 20: Lipid Bilayer, Conformational Change, Hydrophile
3 Nov 2014
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Document Summary
To share information within cells the mechanism is called signal transduction. Cells when responding to stimulus they secrete ligands. Signalling molecules: hormones, chemical messengers secreted by glands, neurotransmitters, chemicals produced by the nervous system. Transmembrane receptors bind to large, hydrophilic molecules that cannot enter the cell by crossing through the lipid bilayer of the plasma membrane . Intracellular nuclear and cytoplasmic receptors directly bind smaller, hydrophobic molecules that readily diffuse through the cell membrane. Transduction occurs when the receptor is activated as a result of its conformational change and transmits, or transduces , the signal to other molecules within the cell. Transduction often involves phosphorylation , dephosphorylation , or another form of chemical transformation . Affinity refers to the strength with which a ligand binds to an enzyme , receptor, or transport protein . Like all transmembrane receptors, enzyme-linked receptors contain two domains.
