What is the structure of a phospholipid?

• A. Two fatty acid tails and a sugar group
• B. Glycerol backbone, two fatty acid tails, and a phosphate group
• C. One fatty acid tail and a phosphate group
• D. Two glycerol molecules and a nitrogen group

Answer: (B)

The structure of a phospholipid is characterized by its composition, which includes a glycerol backbone, two fatty acid tails, and a phosphate group. The glycerol serves as the central component to which the fatty acid tails are attached. Each of these tails is hydrophobic, meaning they repel water and contribute to the overall non-polar nature of the lipid.

The phosphate group, however, is hydrophilic (water-attracting), allowing the phospholipid to interact with aqueous environments. This unique combination of hydrophobic tails and a hydrophilic head (the phosphate group) enables phospholipids to arrange themselves into bilayers, which are fundamental to the structure of cell membranes. This bilayer formation is critical for maintaining cellular integrity and regulating the movement of substances in and out of the cell.

In summary, the correct answer captures the essential components and structure that define a phospholipid, highlighting its significance in biological membranes.