Human nerve cells transport sodium ions against their concentration gradient from lower to higher concentrations via a mechanism known as
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Answer: D. Active transport
Explanation
Active transport moves sodium ions across nerve cell membranes against their natural concentration gradients. Cellular energy derived from ATP molecules is consumed to drive this vital transmembrane pumping process. Specialized protein pumps maintain electrochemical balances necessary for nerve impulse transmission. Cell membranes regulate the passage of ions and molecules using passive and active transport mechanisms. Concentration gradients cause substances to diffuse naturally from regions of high to low concentration. Sodium-potassium pumps are essential membrane proteins that hydrolyze ATP to transport ions.
Neurons require continuous energy supplies to maintain resting potentials for fast signal transmission. Neurological disorders can arise when cellular energy failure disrupts normal ion pump functions. Pharmacologists target sodium pumps with specific drugs to treat various cardiovascular and neural conditions. Diffusion is a passive movement of molecules down a concentration gradient without consuming energy. Passive transport allows substances to cross membranes without requiring direct cellular energy expenditure. Osmosis refers specifically to the passive movement of water molecules across permeable membranes.
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