What functional group do fatty acids possess?

Fatty acids possess a carboxyl group (-COOH) as their functional group. This group is essential because it has both a carbonyl (C=O) and a hydroxyl (-OH) component, which together characterize the carboxylic acids. The presence of the carboxyl group in fatty acids is significant as it provides the acid properties, making them capable of donating a hydrogen ion (H+) in solutions, which is crucial for their role in biological systems, such as in energy storage and metabolism.

In addition, the hydrocarbon chain of the fatty acid is hydrophobic, while the carboxyl group is polar and hydrophilic. This dual characteristic enables fatty acids to participate in various biological functions, including the formation of cell membranes and serving as signaling molecules.

The other functional groups listed do not define fatty acids. The hydroxyl group is commonly found in alcohols and sugars, the amino group is a characteristic of amino acids, and the carbonyl group is typically associated with aldehydes and ketones. While some of these groups can be part of larger molecules that may interact with fatty acids, they do not confer the specific identity and function associated with fatty acids themselves.