BI110 Lecture Notes - Lecture 19: Glycogen, Adrenal Gland, Signal Transduction
Document Summary
Binding of a signal molecule to a surface receptor change the conformation of the receptor to allow entry of the signal molecule. Example: stimulation of glycogen breakdown in liver cells by epinephrine: sutherland (won nobel prize, studied secretion of hormone epinephrine by adrenal gland. Leads to activation of enzyme for glycogen to glucose conversion. Reception by a cell-surface receptor: signal molecules. Integral membrane glycoproteins: responses usually rapid, short-lived events. Reception by a receptor within cell: signal molecules. Hormone-binding domain & dna-binding domain: responses occur over a longer time. Signal molecule must have some hydrophobic properties in order to cross the membrane. Integral membrane proteins --> glycoproteins: binding of a signal molecule. Induces molecular change in receptor that activates it cytoplasmic end. Epinephrine made in adrenal gland but sensed by cells in the liver (only liver has the surface receptors for epinephrine) High concentration of signal molecules results in case like (b) in the diagram above.