LIFESCI 7C Chapter Notes - Chapter 9.4, 28.3, 10.1: Adenylyl Cyclase, Cell Adhesion, Cell Membrane
Document Summary
Chapter 9. 4: g protein-coupled receptors & short-term responses. The first step in cell signaling is receptor activation. When it is bound to gtp, it is on, or active. When it is bound to gdp, it is off, or inactive. Some g proteins are composed of three subunits, called the (cid:573) (cid:523)alpha(cid:524), (cid:574) (cid:523)beta(cid:524), and (cid:523)gamma(cid:524) subunits. The (cid:573) subunit is the part of the g protein that binds to either gdp or gtp. When gdp bound to the (cid:573) subunit is replaced by gtp, the (cid:573) subunit separates from the (cid:574) and subunits. Second messenger: an intermediate cytosolic signaling molecule that. Signals are often amplified in the cytosol transmits signals from a receptor to a target within the cell. (first messengers transmit signals from outside the cell to a receptor. ) First, a single receptor bound to adrenaline can activate several g protein molecules. Second, each molecule of adenylyl cyclase catalyzes the production of large amounts of the second messenger camp.
