Kaplan Nursing Entrance Practice Exam 2026 – The All-in-One Guide to Exam Success!

Phospholipids play a crucial role as a structural component of the plasma membrane. They are arranged in a bilayer, with their hydrophilic (water-attracting) heads facing outward towards the aqueous environments both inside and outside the cell, while the hydrophobic (water-repelling) tails face inward, away from the water. This unique arrangement creates a semi-permeable membrane that protects the cell and regulates what enters and leaves, maintaining the cell's internal environment.

The membrane's structure, primarily composed of phospholipids, provides fluidity and flexibility, allowing for the movement of proteins and other molecules within the membrane. This structural integrity is essential for the overall function of the cell, as it helps to support cell communication, signaling, and transport processes.

Energy storage is not a primary function of phospholipids; rather, it is typically associated with lipid molecules such as triglycerides. Signal transduction refers to the mechanisms through which cells communicate, often involving receptors and secondary messengers, rather than the foundational role of phospholipids in forming the membrane. Protein synthesis is a separate cellular process involving ribosomes and is not directly related to the function of phospholipids in membrane structure.