Primary And Secondary Active Transport |link| Link

Introduction Cellular life depends on the ability to move substances across the plasma membrane against their concentration gradient (from low to high concentration). This process, known as active transport , requires energy because it opposes the natural tendency toward diffusion (entropy). Based on the direct source of this energy, active transport is divided into two categories: Primary Active Transport and Secondary Active Transport . 1. Primary Active Transport Definition: The transport of molecules against their concentration gradient using energy directly from the hydrolysis of adenosine triphosphate (ATP).