What characterizes a fatty acid?

A fatty acid is characterized as an organic acid that typically contains a chain of carbon atoms ranging from about 4 to 24. This carbon chain is usually hydrophobic, meaning it does not mix well with water, which is an important feature because it influences how fatty acids behave in biological systems. The length of the carbon chain can vary, and the presence of double bonds can classify fatty acids as either saturated or unsaturated, but the key defining feature is indeed the carbon atom count within that range.

While other attributes such as saturation levels and functional groups may apply, they do not solely define what a fatty acid is. The aspect of being an organic acid with a carbon chain length of 4-24 encompasses both saturated and unsaturated types, affirming the diversity of fatty acids found in nature.