Chapter 4.1, Problem 1CS

Core Skill: Connections Look back at Figure 3.11. What is the physical/chemical reason why phospholipids tend to form a bilayer?

Figure 3.11 Structure of phospholipids, (a) Chemical structure and space-filling model of phosphatidylcholine, a common phospholipid found in living organisms. Phospholipids contain both polar and nonpolar regions, making them amphipathic. The fatty-acid tails are nonpolar. The rest of the molecule is polar, (b) Arrangement of phospholipids in a biological membrane, such as the plasma membrane that encloses cells. The polar regions of the phospholipids face the watery environment, whereas the nonpolar regions associate with each other in the interior of the membrane, forming a bilayer.