And unlike our carbohydrates and proteins, which are water soluble, so that means they are polar and which are polymers. So that means they consist of individual repeating units. Our lipids are not water soluble, so that means they do not dissolve in water they do not dissolve in a polar solvent. And we'll see what that means in just a moment. And lipids are not polymers. They are not composed of these individual units like the carbohydrates and proteins are.