How do dissolved substances move in and out of cells?
Through cell membranes by diffusion
What is the definition of diffusion?
The movement of particles from an area of high concentration to an area of low concentration through a semi-permeable membrane.
What two factors will affect the rate of diffusion?
Temperature and concentration
What is a concentration gradient?
A difference in concentration between two areas next to each other.
Name two locations in the body where diffusion is important.
Lungs and small intestines
Which important gas passes through cell membranes into cells?