Chemical essential to cellular metabolism, for short

ATP

Think of the molecule often called the "energy currency" of cells, produced in mitochondria during respiration. Its full name includes the word "tri-" for its three phosphate groups.

This clue points to ATP, which stands for adenosine triphosphate—the primary energy-carrying molecule in cells. The phrase "for short" signals that the answer is an abbreviation, while "chemical essential to cellular metabolism" directly describes ATP's role in powering biological processes. It’s a straightforward definition with no wordplay, just a hint to think of the well-known three-letter shorthand.