Fuentes AM, Amábile-Cuevas CF

Idioma: Español
Referencias bibliográficas: 50
Paginas: 86-95
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RESUMEN

El agua juega un papel fundamental en biología. La molécula de H₂O tiene propiedades fisicoquímicas inusuales, gracias a su estructura en estado líquido, sigue siendo motivo de controversia. Establece puentes de hidrógeno entre sí y con otras moléculas con carga eléctrica, lo que define la hidrosolubilidad de dichas moléculas. La evolución prebiótica privilegió las reacciones químicas en agua, y su separación en vesículas rodeadas de lípidos dio origen a las primeras células.
Las principales moléculas biológicas son hidrosolubles o amfipáticas; alrededor de ellas se forman esferas de solvatación, que tienen un papel crucial en su función biológica. La forma en que el agua se organiza alrededor de los iones probablemente explica su localización intra o extracelular. Además de ser el solvente en el que ocurren, muchas reacciones bioquímicas requieren o forman agua. Fisiológicamente, resulta imposible generalizar sobre la cantidad de agua que requiere beber el ser humano para estar sano. Sin embargo, la sed es un indicador confiable de la necesidad de beber agua. La sed surge cuando hay alteraciones en la osmolalidad plasmática. Aun así, en algunas enfermedades y en ciertas edades, la sed puede no ser suficiente para conducir al consumo necesario del agua. Para esos casos es necesario disponer de algoritmos, más que recomendaciones de consumo.
El agua también es necesaria para eliminar desechos hidrosolubles por la orina. La función renal está estrechamente regulada por el sistema renina-angiotensina-aldosterona, que coordina el funcionamiento renal y cardiovascular, y la sed misma.

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