AAMC FL Practice Exam

Which of the following is true about fatty acids?

1. They have a carboxyl group at one end

2. They can only be saturated

3. They cannot contain double bonds

4. They are always branched chains

The correct answer is: They have a carboxyl group at one end

Fatty acids are organic compounds characterized by a long hydrocarbon chain and a carboxyl group (-COOH) at one end. This carboxyl group is crucial as it defines the acidic nature of fatty acids and allows them to participate in various biochemical reactions. The hydrocarbon chain can vary in length and can be either saturated, containing only single bonds, or unsaturated, which includes one or more double bonds between carbon atoms. The presence of double bonds introduces kinks in the structure and affects the physical properties of the fatty acids, such as melting point and fluidity. In contrast, the notion that fatty acids can only be saturated, cannot contain double bonds, or are always branched is inaccurate. Fatty acids exist in both saturated and unsaturated forms, and while some fatty acids can be branched, many are linear. The fundamental structure of a fatty acid being defined by the carboxyl group is what makes option A true.