Advanced Placement (AP) Biology Practice Exam

FAD is primarily involved in which type of chemical reactions?

1. Oxidation-reduction reactions

2. Hydrolysis reactions

3. Condensation reactions

4. Fermentation processes

The correct answer is: Oxidation-reduction reactions

FAD, or flavin adenine dinucleotide, is primarily involved in oxidation-reduction reactions, also known as redox reactions. These are chemical processes where electrons are transferred between molecules, leading to a change in the oxidation states of the participating compounds. FAD acts as an electron carrier, accepting electrons and protons during metabolic pathways, particularly in cellular respiration. In cellular metabolism, FAD is reduced to FADH2 during the citric acid cycle, where it captures and transports electrons to the electron transport chain. This transfer of electrons is crucial for the production of ATP, the energy currency of the cell. As a coenzyme, FAD plays a vital role in various enzymatic reactions, facilitating energy production and other biosynthetic processes. Other types of reactions mentioned in the choices, such as hydrolysis, condensation, and fermentation, do not primarily involve FAD. Hydrolysis refers to the breakdown of compounds through the addition of water, condensation involves the joining of molecules with the loss of water, and fermentation is an incomplete form of respiration that typically does not prominently involve FAD. Thus, the role of FAD in oxidation-reduction reactions is fundamental to its function in metabolic processes.