Joke Collection Website - Mood Talk - The Na+-K+ pump is taken as an example to illustrate the active transport process of cell membrane.

The Na+-K+ pump is taken as an example to illustrate the active transport process of cell membrane.

The characteristics of active transportation are: ① reverse concentration gradient (reverse chemical gradient) transportation; 2 need energy; ③ Both of them have carrier proteins.

The energy required for active transportation mainly includes: ① ion gradient power in cooperative transportation; ② ATP-driven pump obtains energy by hydrolyzing ATP; (3) optically driven pump uses light energy to transport substances, which exist in bacteria.

Na+-K+ pump: A tetramer consisting of two large subunits and two small subunits, which is actually Na+-K+ATPase, is distributed in the plasma membrane of animal cells.

Working principle of sodium-potassium pump;

(1) Na+-K+ ATPase undergoes conformational changes through phosphorylation and dephosphorylation, resulting in changes in its affinity with na+and k+.

(2) Na+ binds to the enzyme inside the membrane, activates the activity of ATPase, decomposes ATP, phosphorylates the enzyme, changes the conformation, and the binding site of Na+ shifts to the outside of the membrane; This phosphorylase has low affinity for Na+ and high affinity for K+, so it releases Na+ outside the membrane and binds to K+.

(3) After K+ binds to phosphorylase, the enzyme is dephosphorylated, and the conformation of the enzyme returns to its original state, so the binding site of K+ turns into the membrane, and the affinity of K+ with the enzyme decreases, thus releasing the combination of K+and Na+ in the membrane.

(4) Each cycle consumes one ATP;; Three Na+ s are shipped out and two K+ s are shipped in.

The function of Na+-K+ pump: ① maintaining the permeability and volume of cells; ② Maintain the intracellular environment with low Na+ and high K+; ③ Maintain the resting potential of cells.