Say an animal is living at low temps, is the heat energy needed to maintain an internal temperature produced by the decomposition of ATP in processes like muscle contraction or is it produced by the formation of ATP in the first place (respiration).
Because I always assumed that Respiration occurred and the ATP was then used in reactions to release energy to heat surrounding cells and tissues but as of today an exam question may have suggested otherwise and I'm just a tad confused :/
The breakdown of ATP is bound to produce a certain amount of heat energy, however, it is not the main source. This would be an A2 explanation of it, for AS, I can't recall being expected to know what exactly produces heat in respiration. Our teachers just taught us that heat is a by-product (or waste product, depending on the situation) of aerobic respiration without quoting where it originates from. You could say that the actual formation of ATP in respiration via chemiosmosis (movement of protons across a membrane down the electrochemical gradient) is what gives off heat.