What does the term "amphipathic" refer to in the context of molecules?

The term "amphipathic" describes molecules that possess both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions. This unique property allows amphipathic molecules to interact with both water and lipids, making them essential in biological systems. For example, phospholipids, which are a key component of cell membranes, have a hydrophilic head that interacts with water and hydrophobic tails that avoid water. This dual nature enables the formation of bilayers in aqueous environments, which is crucial for the structure and function of cellular membranes. The presence of both types of regions allows amphipathic molecules to perform various roles within biological systems, such as forming structures or facilitating transport across hydrophilic environments.