Certified Dietary Manager (CDM) Practice Exam

Which type of chain is characteristic of polyunsaturated fats?

1. Single bonds only

2. More than one double bond

3. Trans bonds only

4. Saturated bonds

The correct answer is: More than one double bond

Polyunsaturated fats are defined by the presence of more than one double bond in their fatty acid chains. This characteristic structure allows them to remain liquid at room temperature and contributes to their role in health, particularly regarding heart health. The multiple double bonds introduce kinks in the molecular structure, preventing the fat molecules from packing closely together, which is crucial for maintaining their liquid state. In contrast, fats with single bonds only are classified as saturated fats, which can solidify at room temperature. Trans fats contain specific geometric arrangements of hydrogen around their double bonds, which is not the characteristic of polyunsaturated fats. Lastly, saturated bonds indicate a lack of double bonds, defining a different group of fats entirely. Understanding these structural differences is critical for recognizing the health implications and dietary sources of these types of fats.