For example, let's say the cell needed to take in more glucose. Paisley would bind to a glucose molecule and a sodium ion on the outside of the cell. As the sodium ion moved down its concentration gradient into the cell, Paisley would use that energy to transport the glucose molecule into the cell against its concentration gradient.
Found in almost every human cell, this pump is the quintessential example of primary active transport. It moves of the cell and two potassium ions ( K+cap K raised to the positive power active transport primary and secondary
Primary active transport is the most direct form of moving solutes against their gradient. It involves transmembrane proteins that function as pumps, utilizing the chemical energy released from ATP hydrolysis to undergo conformational changes. The quintessential example is the sodium-potassium pump (Na⁺/K⁺ ATPase), found in the plasma membrane of virtually all animal cells. This pump actively exports three sodium ions (Na⁺) out of the cell while importing two potassium ions (K⁺) inward for each molecule of ATP broken down into ADP and inorganic phosphate. This simultaneous, counter-transport action establishes a steep electrochemical gradient: a high concentration of Na⁺ outside the cell and a high concentration of K⁺ inside. This gradient is not merely a byproduct; it is a critical store of potential energy used for a variety of cellular functions, including nerve impulse propagation and osmotic balance. Other examples of primary active transport include calcium pumps (Ca²⁺ ATPase), which sequester calcium ions into the sarcoplasmic reticulum of muscle cells, and proton pumps (H⁺ ATPase) in plants and fungi, which acidify vacuoles or the external environment. In all cases, the pump’s energy source is the direct cleavage of ATP. For example, let's say the cell needed to