NANP Board Practice Exam

Which of the following is true about polyunsaturated fatty acids?

1. Contain no double bonds

2. Hold all the hydrogen they can

3. More than one double bond between carbon atoms

4. Single bond between carbon atoms

The correct answer is: More than one double bond between carbon atoms

Polyunsaturated fatty acids are characterized by having more than one double bond between the carbon atoms within their fatty acid chains. This structural feature is important because it influences the properties and functions of these fats in the body. Polyunsaturated fatty acids can be found in various food sources, such as fatty fish, walnuts, flaxseeds, and certain vegetable oils. The presence of multiple double bonds affects the fluidity of the fatty acids and contributes to various health benefits, such as lowering LDL cholesterol levels and reducing inflammation. For these reasons, polyunsaturated fatty acids are often recommended as part of a heart-healthy diet. The other options do not accurately describe polyunsaturated fatty acids. For instance, the first choice refers to fatty acids that contain no double bonds, which describes saturated fatty acids instead. The second option suggests that polyunsaturated fatty acids hold all the hydrogen they can, which is not true because the presence of double bonds means that fewer hydrogen atoms are bonded to the carbon chains. Lastly, the fourth choice refers to fatty acids with only single bonds, which defines saturated fatty acids as well. Thus, the distinction of having more than one double bond truly defines polyunsaturated fatty acids.