Primary creates the gradient; Secondary uses it. Both are essential for keeping your cells functioning! 🔋
| Type | Direction relative to driving ion | Example | |------|----------------------------------|---------| | | Both molecules move in the same direction | Na⁺-glucose symporter (SGLT) in intestinal/kidney cells | | Antiport (Countertransport) | Molecules move in opposite directions | Na⁺/Ca²⁺ exchanger (NCX) in cardiac muscle; Na⁺/H⁺ exchanger | primary active transport vs secondary active transport
Secondary active transport does not use ATP directly. Instead, it couples the movement of one molecule down its electrochemical gradient (established by primary active transport) to drive the movement of another molecule against its gradient. Primary creates the gradient; Secondary uses it