The membrane shows fluid behavior because of movements and packing variations among its lipids and proteins. Integral membrane proteins 2. These methods are termed passive transport processes. Examples of substances that do not require energy to move through the cell membrane are oxygen, carbon dioxide, and small electrically neutral molecules. Other substances require energy to cross the cell membrane.
Gradients can also occur with differences in pressure, temperature or electric charge.
In simple diffusion, each molecule will move down its gradient independent of any other substance that may be present. We will discuss what happens to the red blood cell when it is put into 3 different types of solutions of varying concentrations of sodium chloride. Isotonic - equal solute concentrations on both sides 2. Hypertonic - describes the fluid having more solutes 3. However, many cells are tightly packed together.