LIFE 102 Lecture Notes - Lecture 20: Signal Transduction, Cell Membrane, Cyclic Adenosine Monophosphate
Document Summary
A series of steps by which a signal on a cell"s surface is converted into a specific cellular response. *pathway similarities suggest that ancestral signaling molecules evolved in prokaryotes and were modified later in eukaryotes. Earl w. sutherland discovered how the hormone epinephrine acts on cells. A signal molecule binds to a receptor protein, causing it to change shape. Binding between ligand and receptor is highly specific. A plasma membrane receptor that works with the help of a g protein. Can trigger multiple signal transduction pathways at once. Acts as a gate when the receptor changes shape. When a signal molecule binds as a ligand to the receptor, the gate allows specific ions, such as na+ or ca2+ through a channel in the receptor. *the extracellular signal molecules that bind to the receptor is a pathway"s first messenger. Small, nonprotein, water-soluble molecules or ions that spread throughout a cell by diffusion. Common with g-protein-coupled receptors and receptor tyrosine kinases.
