BIOL130 Final: Unit 8 Exam notes
Document Summary
Decreased rate of firing --- heart pacemaker cell. If the signal directly to the target- fast. Most signals bind to receptor on plasma membrane. Small (non-protein) molecules that relay signals from cell surface receptors to target molecules within cell. Intracellular signal molecules often act as molecular switches. Signaling by protein phosphorylation: kinase adds phosphate (on, remove phosphate turns (off) Signaling by gtp-binding protein: replacing gdp with gtp (on, if gtp is hydrolyzed then a phosphate group is taken out (off) Phosphorylation cascade -steps that occurs when signal molecule binds to receptor causing a chain of reaction (step process) to occurs that eventually lead to a cellular response. There are many steps so there are more opportunities for integration and regulation. Switch from active (gtp binded to protien) to inactive state (gdp binded to protein). To turn off gtp is hydrolyzed to form gdp and the binding of gdp turns the protein off.