The osmotic pressure of red blood cells against water is 7.63 bar. If you are asked to make 1 liter of isotonic solution for red blood cells using Red Bull, assuming negligible functions of caffeine receptors and glucose transporters on the surface of the cells, calculate how many cans of Red Bull do you need.

Atp is is our little "pocket" of energy. of course, if you have too little, then it means you have too little energy, and you'll pass out. the way to not have enough, is to have no energy sources (glucose, fats, proteins). you can't have too many atp molecules. cycles like the krebs cycle produce it, but if you have too much of any substrate (or too little for that matter), the cycle stops and atp is no longer made (it stops until substrate levels are such that the process can go on). in any case, this is unlikely since atp is constantly hydrolyzed and remade, even while you're asleep. you won't have too much. if you have zero, you are dead or dying.