Sodium potassium ATPase pump.
Active transport uses energy to move substances against the concentration gradient.
diffusion is the movement of a substance with respect to concentration and gradient a substance traveling with the concentration gradient ( simple diffusion) a substance traveling against the concentration gradient (active diffusion)
it is called a concentration gradient.
Activetransportis the movement of a substance across a cell membrane against its concentration gradient (from low to high concentration).
A substance moving from an area of higher concentration to an area of lower concentration down it's concentration gradient.
If a substance moves down its concentration gradient, it means that it is moving from an area where it has a high concentration to an area where it has a low concentration. This is known as diffusion.