A concentration gradient in the electrolyte is illustrated. ·If the electrolyte is unstirred, the gradiant causes H-ion diffusion to the surface, where they capture electrons (reduction) to become ...

This is due to the random movement of the molecules. The direction of diffusion is said to be 'down' or 'with' the concentration gradient. Diffusion stops when the concentration of the substance ...

It occurs down a concentration gradient - molecules move from an area of high to lower concentration. This does not require a supply of energy because diffusion is a spontaneous process.

The presence of a Dpp gradient ... its strongest concentration (visualized as the brightest green fluorescence) down the center of the imaginal disc. The posterior and anterior diffusion of ...