Question

what property of water is probably the most important for the functioning of organisms at the molecular level

Answer 1

not sure. i think that the duality of water and lipid which allows for compartmentalization comes next though. lipid membranes, in which van-der-vals forces are dominant vs polar, water based volumes comes next in order

Answer 2

I think one of the main function of water deals with homeostasis. If an organism doesn't have enough water in the system, cells shrink to accommodate for the loss. When there's too much, cells swell and may even burst.

Answer 3

This would very likely be the existence of water as a amphoteric ion, a 'zwitter ion'. It can both donate a hydrogen acting as an acid (to become OH-) or it can accept a hydrogen acting as a base (to become H3O+). This duality allows water to help compensate for pH imbalances temporarily until the body accommodates in a manner with lasting effects.

Answer 4

Water is essential as a solute and solvent and as a carrier of a myriad of nutrients, metal ions, cytokines and basically everything a wee little cell need to function. I can't think of one MOST important factor but I would definitely say keeping the cells alive is kind of important.