Physiology 3140A Lecture Notes - Lecture 4: Inositol Trisphosphate, Calcium In Biology, Glycerophospholipid

• School: Western University
• Department: Physiology
• Course: Physiology 3140A
• Professor: John Di Guglielmo

Document Summary

Regulation of resting ca2+ levels in the cell. Can drag in large amounts of water. Transient opening of ca2+ channels leads to increases in local ca2+ concentrations in cytosol, and activation of ca2+-dependent proteins in cell. Pumps ca2+ out of cytoplasm when concentration reaches 10-6 m. Uses atp to move ca2+ out of cytoplasm. Pumps ca2+ out of cytoplasm when concentration goes above 10-6m. Difference bw the two: some may be present in some cells vs in other cells. Ca2+ moved into lumen of er from cytoplasm. Functions when ca2+ increases to a concentration about 10-6 m therefore high-affinity: (cid:498)high-affinity(cid:499): km very. Relatively low storage capacity compared to other mechanisms favourable. Ca2+ moved into lumen of mitochondria from cytoplasm. Functions when ca2+ increases to high levels about 10-5m, therefore low affinity, protective mechanism. Relatively high storage capacity compared to other mechanisms. Ca2+ binds specifically to several binding proteins in cytoplasmic compartment. Ca2+ and thus does not contribute to concentration of.