Advanced Placement (AP) Biology Practice Exam

What type of bonds are found in saturated fats?

1. Carbon-carbon double bonds

2. Carbon-hydrogen double bonds

3. Single bonds only between carbon atoms

4. Ionic bonds between fatty acids

The correct answer is: Single bonds only between carbon atoms

Saturated fats are characterized by having only single bonds between carbon atoms. This structure is crucial because it allows the carbon chains to pack closely together, resulting in fats that are typically solid at room temperature. The absence of double bonds means that all available bonding sites of the carbon atoms are filled with hydrogen atoms, which is why they are termed "saturated." The presence of only single bonds in saturated fats contrasts with unsaturated fats, which contain one or more double bonds that introduce kinks or bends in their structure, preventing tight packing and creating a liquid form at room temperature. This fundamental difference in bonding is key to understanding the physical properties and biological functions of various types of fats.