What characterizes an unsaturated fatty acid?

An unsaturated fatty acid is characterized by having one or more double bonds in its hydrocarbon chain. This structural feature has significant implications for the physical properties of the fatty acid. The presence of double bonds introduces kinks or bends in the fatty acid chain, preventing the molecules from packing closely together. As a result, unsaturated fatty acids typically remain liquid at room temperature, which is a key characteristic when distinguishing them from saturated fatty acids that have only single bonds and tend to be solid at room temperature.

The ability to form double bonds also plays an important role in the biological functions of unsaturated fatty acids, contributing to their presence in various dietary fats and oils that are known for their health benefits.