USA Biology Olympiad (USABO) Practice Exam

Which of the following is a key function of ATP in biological systems?

1. Storage of genetic information

2. Transportation of electrons

3. Energy currency for cellular processes

4. Formation of cellular membranes

The correct answer is: Energy currency for cellular processes

ATP, or adenosine triphosphate, serves as the primary energy currency in biological systems. It plays a critical role in energizing a wide variety of cellular processes, enabling organisms to perform functions necessary for survival and growth. When ATP is hydrolyzed, it releases energy that can be utilized for biochemical reactions, such as muscle contraction, biochemical synthesis, and active transport across membranes. This energy release occurs when the high-energy phosphate bonds within ATP are broken, particularly the bond connecting the third phosphate group. This characteristic makes ATP essential for maintaining cellular energy balance, powering reactions that would otherwise not occur spontaneously. In contrast, the other options have distinct functions that do not align with the primary role of ATP. While storage of genetic information is primarily a function of nucleic acids like DNA and RNA, the transportation of electrons is typically associated with molecules involved in redox reactions, like NADH and FADH2. The formation of cellular membranes involves lipids and structural proteins rather than ATP specifically providing energy for that process. Thus, the key function of ATP as the energy currency in cells is what distinguishes it from these other biological roles.