The introduction of powerful microscopes, optic first, electronic later and confocal more recently, combined with cell fractionation, ultra-centrifugation and other advanced techniques, showed that our cells are microstructures that function, and conceived the idea that a function is nothing but the manifestation of a structural change and, conversely, every change of structure elicits some sort of function.
Toda función es una manifestación de algún cambio estructural, y al revés, no hay cambio de estructura que no tenga una consecuencia funcional.