what is a semipermeable membrane made of
Luckily there are three types of membranes to help her. A membrane is a material or tissue that acts as a barrier or divider between two regions. A permeable membrane allows all substances to flow freely across the membrane. A semi-permeable membrane allows some substances to cross the membrane, but not others. An impermeable membrane blocks the movement of all substances. To unlock this lesson you must be a Study.com Member.