What do the letters ATP stand for?

• A. Adenosine diphosphate
• B. Adenosine monophosphate
• C. Adenosine triphosphate
• D. Adenosine triphosphate synthase

Answer: (C)

ATP stands for adenosine triphosphate, the molecule that stores and transfers energy in cells. Adenosine is built from adenine attached to a ribose sugar, and triphosphate means there are three phosphate groups in a row. Those phosphate bonds hold a lot of energy, and releasing energy by removing a phosphate powers many cellular processes, including stages of photosynthesis that drive sugar synthesis. This name reflects the actual structure: adenosine plus three phosphates. The other options describe related molecules or an enzyme, not the molecule’s name: two phosphates correspond to ADP, one phosphate to AMP, and ATP synthase is the enzyme that helps make ATP rather than the name of the molecule itself.