What does ATP stand for, and what is its role in cells?

• A. Adenosine triphosphate - energy storage and transfer unit within cells
• B. Adenosine diphosphate - energy storage and transfer unit within cells
• C. Amino acid energy carrier
• D. Acetyl-CoA

Answer: (A)

ATP is the cell’s energy currency. It stands for Adenosine triphosphate, a molecule with three phosphate groups. The energy stored in the bonds of these phosphates is released when the terminal phosphate is removed, producing ADP and inorganic phosphate, and that energy powers activities like muscle movement, active transport across membranes, and making larger molecules. Cells continually regenerate ATP from ADP and Pi through cellular respiration or other pathways.

The other options don’t fit because adenosine diphosphate is produced after ATP loses a phosphate rather than serving as the main energy carrier; amino acids aren’t a direct energy currency; and Acetyl-CoA is an important metabolic intermediate that helps feed energy production but isn’t the primary energy-storage molecule itself.