Final answer:
Phospholipids are amphipathic molecules, consisting of hydrophobic fatty acid tails and a hydrophilic phosphate head. They are key components of cellular membranes, forming a bilayer that regulates the passage of materials.
Step-by-step explanation:
The correct answer to the question 'Which of the following is true of phospholipids?' is that phospholipids are amphipathic molecules. This means that a phospholipid has both a hydrophobic (water-fearing) and a hydrophilic (water-loving) part. Specifically, in a phospholipid, the fatty acid chains are hydrophobic and prefer to avoid water, while the phosphate-containing group is hydrophilic and seeks to interact with water.
Each phospholipid molecule has a polar head that faces towards water, and these polar heads are attracted to water due to their charge. The nonpolar fatty acid tails, on the other hand, face towards each other, away from the water, thus forming a bilayer in cell membranes.
Phospholipids are the main component of cell membranes in all living organisms, as they form a barrier that protects the cell and controls the movement of substances in and out of the cell.