What type of molecule has both hydrophilic and hydrophobic parts?

Amphipathic molecules are characterized by having both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions within their structure. This dual nature allows them to interact with both polar substances, like water, and nonpolar substances, such as lipids. A classic example of amphipathic molecules is phospholipids, which have a hydrophilic head and hydrophobic tails.

These properties are crucial in biological systems, particularly in the formation of cell membranes, where the hydrophilic heads face outward towards the aqueous environment, while the hydrophobic tails face inward, away from water. This arrangement creates a bilayer that serves as a barrier and allows for the compartmentalization of cellular processes.

Other options do not encapsulate this critical characteristic. Micelles, for instance, form from amphipathic molecules, but they themselves are the structures created for emulsifying agents in solutions. Hydrosols refer to colloids with particles dispersed in water and do not imply any hydrophilic or hydrophobic character. Polymers are larger macromolecules formed by repeated subunits but don’t necessarily have both hydrophilic and hydrophobic components. Thus, the most accurate answer is that amphip