Advanced Placement (AP) Biology Practice Exam

Which characteristic is true for unsaturated fats?

1. They are solid at room temperature

2. They contain carbon to carbon double bonds

3. They are commonly found in animal fats

4. They only contain single bonds

The correct answer is: They contain carbon to carbon double bonds

Unsaturated fats are characterized by the presence of one or more carbon-carbon double bonds within their fatty acid chains. This structural feature introduces kinks in the fatty acid tails, preventing the molecules from packing tightly together, which is why unsaturated fats tend to be liquid at room temperature. The existence of double bonds is what differentiates unsaturated fats from saturated fats, which contain only single bonds between carbon atoms and are typically solid at room temperature. This distinction is essential in understanding the physical properties and nutritional implications of these types of fats. The presence of double bonds is significant for various biological functions, including fluidity in cell membranes and other metabolic processes.