Final answer:
Energy in biological systems is commonly released as heat during exothermic chemical reactions, or it is used to create ATP, the energy currency in cells that powers various biological processes.
Step-by-step explanation:
Energy can be released as heat or released to form ATP (adenosine triphosphate).
When atoms bond together to form molecules, energy is required. Conversely, when these bonds are broken, such as in the breakdown of glucose during cellular respiration, energy is released. In biological systems, chemical reactions take place where bonds between atoms are formed and broken. If new bonds formed are stronger than the ones broken, energy is usually released as heat. This heat is the byproduct of the exothermic reaction.
Moreover, in living cells, ATP is a crucial molecule that stores and transfers energy. When glucose is broken down in cells through a process like glycolysis, the energy from the glucose is used to form ATP from ADP (adenosine diphosphate) and inorganic phosphate. ATP then serves as an energy currency in the cell, transferring energy to other reactions where it is needed.