Advanced Placement (AP) Biology Practice Exam

Which of the following best defines anabolism?

1. Breaking down molecules

2. Using energy to form bonds and molecules

3. No energy is used

4. Only occurs in prokaryotes

The correct answer is: Using energy to form bonds and molecules

Anabolism is a biochemical process that involves the synthesis of complex molecules from simpler ones, which generally requires an input of energy. This process is essential for growth, repair, and the maintenance of cellular structures. The correct definition centers around the use of energy to form chemical bonds, leading to the creation of larger biological macromolecules like proteins, nucleic acids, carbohydrates, and lipids. In contrast, breaking down molecules, which is characteristic of catabolism, is not a part of anabolism. Additionally, the statement that no energy is used is incorrect, as energy is fundamentally required for anabolic reactions to proceed. Lastly, the notion that anabolism only occurs in prokaryotes is misleading, as both prokaryotic and eukaryotic organisms undergo anabolic processes. Therefore, the definition aligning with using energy to form bonds and molecules accurately captures the essence of anabolism.