Dynamic reserve
Dynamic reserve, in the context of the dynamic energy budget theory, refers to the set of metabolites (mostly polymers and lipids) that an organism can use for metabolic purposes. These chemical compounds can have active metabolic functions, however. They are not just "set apart for later use." Reserve differs from structure in the first place by its dynamics. Reserve has an implied turnover, because it is synthesized from food (or other substrates in the environment) and used by metabolic processes occurring in cells. The turnover of structure depends on the maintenance of an organism. Maintenance is not required  for reserve. A freshly laid egg consists almost exclusively of reserve, and hardly respires. The chemical compounds in the reserve have the same turnover, while that in the structure can have a different turnover, and so it depends on the compound. Functionality. Reserves are synthesized from environmental substrates (food) for use by the metabolism for the purpose of somatic maintenance (including protein turnover, maintenance of concentration gradients across membranes, activity and other types of work), growth (increase of structural mass), maturity maintenance (installation of regulation systems, preparation for reproduction, maintenance of defense systems, such as the immune system), maturation (increase  of the state of maturity) and reproduction. This organizational position of reserve creates a rather constant internal chemical environment, with only an indirect coupling with the extra-organismal environment. Reserves as well as structure are taken to be generalised compounds, i.e. mixtures of a large number of compounds, which do not change in composition. The latter requirement is called the strong homeostasis assumption. Polymers (carbohydrates, proteins, ribosomal RNA) and lipids form the main bulk of reserves and of structure. Some reasons for including reserve are to give an explanation for (from ):