AP BIOLOGY

Detailed explanation-1: -Most plasma membranes consist of approximately 50% lipid and 50% protein by weight, with the carbohydrate portions of glycolipids and glycoproteins constituting 5 to 10% of the membrane mass.

Detailed explanation-2: -Lipids constitute approximately 50% of the mass of most cell membranes, although this proportion varies depending on the type of membrane. Plasma membranes, for example, are approximately 50% lipid and 50% protein.

Detailed explanation-3: -Above 45°C. Phospholipid bilayer begins to break down. Increasing kinetic energy allows the phospholipids to move far away from each other, which destroys the structural integrity of the membrane, causing it to “melt”.

Detailed explanation-4: -There are three major classes of membrane lipid molecules-phospholipids, cholesterol, and glycolipids.

Detailed explanation-5: -The basic structural framework of the plasma membrane; two back‐to‐back layers made up of three types of lipid molecules-phospholipids, cholesterol, and glycolipids; hydrophilic “heads” face outward and the hydrophobic “tails” face inward. Lipids that contain phosphorus; about 75 percent of the plasma membrane.