Physiology 3120 Lecture Notes - Lecture 3: Homeostasis, Osmotic Concentration, Molality

• School: Western University
• Department: Physiology
• Course: Physiology 3120
• Professor: Tom Stavraky

Document Summary

A form of carrier mediated transport: chemical specificity, competitive inhibition by structurally similar molecules, saturation kinetics. *moves substances against the concentration gradient: requires energy (atp, site on active transport carrier for atpase which hydrolyzes atp to adp or amp and the consequent release of energy powers carrier movement. Pumps 3 na+ out and 2 k+ in (against their concentration gradients) for every atp split. High concentration of k+ on the inside, low concentration of k+ on the outside. Low concentration of na+ on the inside, high concentration of na+ on the outside. At rest all binding sites empty, atp attached to the intracellular side (where atp is being made) but not split/hydrolysed: na+/k+ pump is never really at rest. It"s always working as long as there"s na+, k+, and atp. Step 1: three na+ bind to their intracellular binding sites. Step 1 to 2: atp is hydrolysed into adp and pi, releasing the energy to the protein.