How does the structure of a phospholipid contribute to cell membrane integrity?

• A. The hydrophilic heads attract water
• B. The hydrophobic tails create a barrier
• C. The saturated fats enhance flexibility
• D. The polar nature allows ion passage

Answer: (B)

The structure of a phospholipid plays a critical role in maintaining cell membrane integrity, particularly through the presence of hydrophobic tails. These hydrophobic tails repel water and create a barrier that separates the internal environment of the cell from the external environment. This property is essential for forming the lipid bilayer, which is a fundamental component of all cell membranes. The bilayer configuration ensures that the membrane is selectively permeable, allowing certain substances to pass while preventing others, thereby maintaining homeostasis within the cell.

The hydrophilic heads of phospholipids face outward toward the aqueous environment, providing stability to the membrane structure, but it is the hydrophobic tails pointing inward that primarily contribute to the formation of this barrier. This dual nature of phospholipids, where one part is hydrophilic and the other is hydrophobic, results in a stable yet dynamic structure that is capable of supporting various functions necessary for the cell, such as signaling and transport.

While other options touch on relevant aspects of cell membranes, they do not capture the primary mechanism of how phospholipid structure supports the integrity of the membrane as effectively as the barrier created by the hydrophobic tails.