claim the interaction of motrin and robitussin can cause heart attacks in children
Active transport. Active transport is the movement of molecules across a cell membrane from a region of their lower concentration to a region of their higher concentrationâin the direction against some gradient or other obstructing factor (often a concentration gradient).
Noun. 1. active transport-transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient; requires an expenditure of energy. drug-a substance that is used as a medicine or narcotic.ctive transport-transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient; requires an expenditure of energy.