BIOL 1201 : Exam 4 Bio Notes
Document Summary
Controls movement of ions across the plasma membrane. Gpcr-activated by bindinb of a first messanger signal molecule. Consists of three different subunits (alpha, beta, and gamma) Gdp is bound to the alpha subunit of the inactive g protein heterotrimer. Alpha subunit with gtp bound and a beta gamma dimer. An activated receptor interacts with the g proteins. The g protein dissociates into alpha-gtp and a beta gamma dimer. Interact with their target enzymes or ion channels. Turned off when an intrinsic gtpase activity of the alpha subunit hydrolyzes gtp to gdp. Membrane receptor is activated by an extracellular signal. G protein transfers the extracellular signal into the entracellular compartment by interacting with a target. The enzyme is modulated (positively and negatively) by different g proteins. Depends on the summation of all the positive and negative signals on the cell camp activates an enzyme called protein kinase signaling components. Membrane receptor g protein- adenylyl cyclase camp protein kinase a.