What is the main role of phospholipids in the body?

Phospholipids play a crucial role in maintaining the structure and function of cell membranes. They are amphipathic molecules, meaning they possess both hydrophilic (water-attracting) and hydrophobic (water-repelling) properties. This unique characteristic allows phospholipids to form bilayers that make up the cell membrane, with their hydrophilic heads facing outward toward the aqueous environment and their hydrophobic tails facing inward, away from water.

This bilayer is fundamental for the integrity of the cell, as it acts as a barrier to protect the internal environment and regulate what enters and exits the cell. Additionally, phospholipids contribute to various cellular processes, including signaling and interaction with proteins, which are vital for cellular communication and function.

The other options do not accurately capture the primary function of phospholipids. Energy storage is primarily handled by fats and carbohydrates, protein synthesis is performed by ribosomes and involves amino acids, and vitamin absorption mainly involves lipids and specialized proteins, but not specifically phospholipids. Thus, the role of phospholipids as a key structural component of cell membranes stands out as their most significant function.