Multiple choice ADP can be joined with a phosphate group by using energy to form ____. NADP ATP NADPH all the above Reveal answer Fill a bubble to check yourself B Correct answer Explanation ADP (adenosine diphosphate) combines with a phosphate group using energy (typically from cellular respiration) to form ATP (adenosine triphosphate), the cell's primary energy currency. This reversible reaction stores and releases biochemical energy.