Question

What is diffusion? What is facilitated diffusion? What is osmosis?

Answer 1

Diffusion is the movement of substances from high concentration to low concentration. Osmosis is the diffusion of water. Facilitated diffusion requires no energy.

Explanation:

Diffusion is the tendency of a substance to move from high concentration to low concentration. Consider a cell membrane that is permeable to glucose. On the right side of the membrane, there is a high concentration of glucose, while on the left side, there is a very low amount of glucose. By diffusion, the glucose on the right side would move across the membrane to the left side until the concentrations of glucose on both sides are equal.

Osmosis is basically diffusion with water. Highly-concentrated water would move to an area with a low concentration of water.

Facilitated diffusion occurs when molecules can cross the cell membrane without any energy being added. The most common example of facilitated diffusion is the movement of water across a cell membrane through transmembrane proteins, which requires no energy. They are simply powered by the concentration differences of the molecules between the two sides of the cell membrane.