BIOL 155 Study Guide - Midterm Guide: Ouabain, Membrane Potential, Hydrophile
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BIOL 155 Full Course Notes
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Document Summary
Ouabain is a chemical that inhibits the sodium-potassium pump in cell membranes. Yes, the na-k-atpase is responsible for setting up the k+ and na+ gradients across the cell membrane. 3 na+ are pumped out for 2 k+ pumped in. K-atpase pumps, there is a net movement of 1 positive charge out of the cell, this imbalance does not contribute significantly to the membrane potential. Rather, k+ leaking out of the cell through leak channels results in a charge separation (negatively charged proteins are trapped within the cell. This makes the inside of the cell negative to the outside. If the na-k-atpase is blocked, the k+ gradient would break down and k+ would no longer leak out. No charge separation would occur and the membrane potential would decline to 0. The ability of the axon to conduct action potentials depends on having an inward sodium gradient and an outward potassium gradient. If you block the na-k-atpase, these gradients would not exist.
