Long-time member here, thought I’d make an account on this forum, seeing as the old one is defunct.
A very small thing, but I think that your cell’s energy levels shouldn’t be referred to as ATP in-game. The problem with this nomenclature is that ATP is far from the only molecule that is viable as an energy carrier within a cell. Even in Earth-based cells, there’s plenty of other energy carriers (GTP, NADH, to name a few) that are merely less common due to being utilized only in very specific reaction chains, rather than being all-purpose like ATP. As far as I know, these other molecules, especially the triphosphate-using ones, are not inherently inferior for energy transport. There was, more than likely, a very healthy dose of chance in the evolutionary ‘decision’ for ATP to be used as the primary energy carrier in the cell. On an alien planet, there’s no reason to assume that ATP is bound to be the energy carrier of choice.
Therefore, I propose two potential ‘solutions’ to this admittedly minor issue:
Simply rename ATP to ‘energy’
Potentially more interesting, have a table of potential energy-carrier molecules and roll a dice at the generation of a new world to see which one is utilized. ATP, GTP, CTP, UTP and dTTP would have the highest chances of appearing, but more rarely, other purines/pyramidines could be used for the first letters.
Just my .02$