AAMC FL Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Phospholipids are essential components of cell membranes and play a crucial role in cellular structure and function. The correct structure of a phospholipid includes one glycerol molecule, one phosphate group, and two fatty acid chains.

The glycerol acts as a backbone to which the phosphate group and fatty acids are attached. The phosphate group is usually charged at physiological pH, making that region hydrophilic (water-attracting), while the two fatty acid tails are hydrophobic (water-repelling). This amphipathic nature—having both hydrophilic and hydrophobic parts—allows phospholipids to spontaneously form bilayers in aqueous environments, a fundamental characteristic of cell membranes.

The other options do not accurately represent the structure of phospholipids. They may include incorrect ratios or components that do not align with what defines phospholipids. For instance, having more than one phosphate group would not fit the typical structure, as would having three fatty acids instead of just two. Understanding this configuration is key to grasping how phospholipids function in biological membranes.