BIO 1140 Lecture Notes - Lecture 11: Signal Transduction, Lipid Bilayer, Cell Membrane
Document Summary
Bio - lec 11 - signal transduction part 1 - feb 23. Don"t need channels to pass across the membrane, since they are soluble. 6 classes (steroids, lipids, peptides/proteins, purines, amines, gases) Communication path taken to reach target cell. Mode of action/interaction with the cell & receptors. Lipophilic (cannot be stored in vesicles) , will diffuse or be bound to transport proteins. Membrane permeable (can reach intracellular receptors (inside cytoplasm or inside nucleus) Once steroids bound to the receptors , together they act like transcription factors. Transcription factor : bound to dna at the tata box (promoter region), turn on or off gene transcription (dna to mrna to protein) 3 classes - depending on what they do. Phospholipase a2 : cuts off the polar head group. Two tail fatty acid , gets processed by enzymes into prostaglandins (pain) and leukotrienes (inflammation) Lipophilic - easy to go through the lipid biliayer. Hydrophilic - hard to get across the membrane.