Fuentes AM, Amábile-Cuevas CF

Idioma: Español
Referencias bibliográficas: 50
Paginas: 7-17
Archivo PDF: 695.30 Kb.

RESUMEN

El agua juega un papel fundamental en la biología. La simple molécula de H₂O tiene propiedades fisicoquímicas inusuales dadas por su estructura en estado líquido, lo que sigue siendo controversial. 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 anfipáticas; 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 intracelular o extracelular. Además de ser el solvente en el que ocurren muchas reacciones bioquímicas, éstas requieren o forman agua. Fisiológicamente, resulta imposible hacer una generalización sobre la cantidad de agua que requiere beber el ser humano para estar sano. La sed, sin embargo, es un indicador confiable de la necesidad de beber agua. La sed surge cuando hay alteraciones en la osmolaridad plasmática. Con todo, en algunas enfermedades y grupos etarios, la sed puede no ser suficiente para conducir al consumo del agua necesaria; en estos casos es necesario disponer de algoritmos, más que recomendaciones de consumo. El agua es necesaria también para la eliminación de desechos hidrosolubles en la orina. La función renal está estrechamente regulada por el sistema renina-angiotensina-aldosterona, que coordina el funcionamiento renal y cardiovascular, la sed misma.

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