Energy — common mistakes

According to Cambridge 9700 Biology, the main function of ATP (adenosine triphosphate) is to act as the immediate and universal energy currency for cells. It links energy-releasing processes like respiration to energy-requiring processes like active transport and synthesis of macromolecules. You can master this concept with our free revision lessons and practice with past papers.

ATP is synthesised from ADP (adenosine diphosphate) and inorganic phosphate (Pi) through a process called phosphorylation. This reaction is catalysed by the enzyme ATP synthase, using energy derived from catabolic reactions such as cellular respiration or light-dependent reactions of photosynthesis.

ATP is preferred over glucose as an immediate energy source because it provides energy in smaller, more manageable packets upon hydrolysis. Glucose, while a large energy store, releases a much larger amount of energy in one go, which could be inefficient and potentially damaging to the cell. ATP allows for precise energy delivery directly to the required cellular processes.