Final answer:
The term amphipathic refers to molecules that have both hydrophilic and hydrophobic regions, with phospholipids being a key example essential in cell membrane structure by forming a lipid bilayer.
Step-by-step explanation:
The term amphipathic describes the characteristic of some molecules that have both hydrophilic (water-loving) and hydrophobic (water-fearing) regions. Molecules with amphipathic properties, such as phospholipids, play a vital role in the structure and function of cell membranes. The hydrophilic head of a phospholipid is attracted to water and the hydrophobic tails are repelled by it, which leads to the formation of the lipid bilayer in cell membranes. This organization of phospholipids in the cell membrane is crucial for the barrier function, allowing the cell to maintain a distinct internal environment from the outside.