Active transport is a way for molecules to move across the plasma membrane. When active, it requires concentration gradient and energy that the cell provides. Osmosis is not involved in active transport. Diffusion is when molecules of a substance move from a higher concentration to a lower concentration. The rate of diffusion is not affected by particle color. However, particle size, temperature, and concentration gradient do affect the rate of diffusion. If a patient is given an IV of pure water, their blood cells would burst, not shrink. The patient would not become rehydrated slowly. Instead, an outstanding level of medical care would be required to address the consequences of giving pure water intravenously.