What happens to the energy that is not used for ATP synthesis during glucose catabolism?

Step-by-step solution

The strategy that the plant cell uses is to catabolize the glucose molecule in such a way that not all the liberated energy goes out as heat. The key is to oxidase glucose not in one step but in several small steps enabling some steps to be just large enough such that the energy released can be coupled to ATP synthesis. How this is done is, essentially, the story of respiration