Which of the following is a nucleotide that acts as an energy currency in cells?

• A. Adenosine triphosphate
• B. Nucleotide
• C. Ribose
• D. Phosphate

Answer: (A)

The main idea is that cells use ATP as their energy currency because it stores energy in its high-energy phosphate bonds. ATP is a nucleotide made of adenine, a ribose sugar, and three phosphate groups. When energy is needed, ATP is hydrolyzed to ADP and inorganic phosphate, releasing a usable amount of energy that powers many cellular processes, from making the molecules cells need to move and grow to transporting substances across membranes. The energy release comes from breaking the bond between the last two phosphate groups, a highly favorable reaction that couples to other cellular work. Other options don’t fit because a nucleotide is just a general category, ribose is only the sugar component, and phosphate by itself is just a phosphate group, none of which serve as the universal energy carrier in cells like ATP does.