It is clear that life on Earth depends on the unusual structure and anomalous nature of liquid water. Organisms consist mostly of liquid water. This water performs many functions and it can never be considered simply as an inert diluent; it transports, lubricates, reacts, stabilizes, signals, structures and partitions. The living world should be thought of as an equal partnership between the biological molecules and water.

In spite of much work, many of the properties of water are puzzling. Enlightenment comes from an understanding that water molecules form an infinite hydrogen-bonded network with localized and structured clustering The middling strength of the connecting hydrogen bonds seems ideally suited to life processes, being easily formed but not too difficult to break. An important concept, often overlooked, is that liquid water is not homogeneous at the nanoscopic level

http://www.lsbu.ac.uk/water/abstrct.html