What are phospholipids composed of?

Phospholipids are crucial components of cell membranes and are primarily composed of glycerol, two fatty acids, and a phosphate group. The structure is important in creating a hydrophilic (water-attracting) "head" due to the phosphate group, and two hydrophobic (water-repelling) "tails" made up of fatty acids. This amphipathic nature allows phospholipids to form bilayers, which are essential for the integrity and functionality of cellular membranes, enabling them to separate internal cell components from the external environment.

The other choices do not accurately describe the composition of phospholipids. Cholesterol and phosphates, while present in cellular membranes, do not define the structure of phospholipids. Amino acids and sugars are fundamental building blocks of proteins and carbohydrates, respectively, rather than lipids. Fatty acids and waxes include types of lipids but do not encompass the specific structure that characterizes phospholipids. Therefore, the first choice correctly identifies the essential components of phospholipids.