Diffusion, water potential, osmosis

Question 1

Define diffusion.

Answer 1

Diffusion is the movement of molecules from aplace of high concentration to an area of low concentration down a conentration gradient.

Question 2

Define osmosis.

Answer 2

Diffusion is the movement of molecules from a place of high concentration to an area of low concentration down a concentration gradient through a semi-permeable membrane.

Question 3

Define water potential.

Answer 3

Water potential refers to the potential energy water molecules have for movement.

We say that water molecules (and remember this definition only applies to the movement of water molecules) move from a place of high concentration to an area of low concentration down a concentration gradient through a semi-permeable membrane by the process of osmosis.

Question 4

What water has the highest possible water potential?

Answer 4

Pure water has the highest possible water potential while water containing any dissolved substances always has a lower water potential.

For example a cell contains water and dissolved substances (for example glucose sugar made during photosynthesis) and therefore has a lower water potential than that of the water surrounding the cell