So certain molecules, such as cholesterol and water can travel through the cell membrane down its electrochemical gradient, much like a ball falls down the gravitational potential gradient. This process does not require any use of energy in the form of ATP, nor does it actually require the use of an integral protein. And this process is known as passive diffusion. Passive means we are not using any type of energy source. So basically the example I can give is this marker falling down its potential gradient. So basically, we have a high potential.