BIOL 2107K Lecture Notes - Lecture 9: Peptide, Signal Transduction, Protein Kinase
Document Summary
Signaling molecules attach to receptor proteins and bind to signaling molecule. Low cell density - not as loud, population too low to stimulate dna uptake. High cell density- signaling peptide concentration high enough to stimulate dna uptake. Molecular events, chemical reactions, cascade cellular response to a given signal. Autocrine- signals diffuse to or affect cells that synthesize them. Paracrine signals diffuse to or affect nearby cells. Receptor location is related to whether the ligands are polar or nonpolar. Nonpolar signals can cross easily while the polar or a signal that is large, cannot diffuse through the plasma membrane, so its receptor is embedded in the membrane. Sodium, potassium, calcium, chlorine pumps usually used, mainly sodium and potassium. And muscle contractions na+ builds up inside the membrane. Phosphatases removes phosphate groups from proteins causing them to become inactive. Based on na+ concentration gradient membrane potential. Influx of sodium (based on ach) binding, yields change in membrane potential activates muscle cell contraction.
