What properties does water possess that make it an essential molecule for life?

·       Solvent – Good for polar substances (salts, sugars, simple alcohols)

·       Heat Capacity – Energy to raise 1kg water by 1^oK. Keeps blood temperature stable

·       Heat of Vaporisation – Good for sweat, absorbs a lot of energy

·       Density and Freezing – Maximum density at 4^oC, cold water insulates warm water underneath. Ice also has a lower density than water so floats

·       Surface Tension and Cohesion – Cohesion drives water up Xylem, Surface tension allows bugs to walk across it

·       Reagent – Hydrolysis reactions, H source in photosynthesis

·       Viscosity – Makes transport easier (Osmosis, swimming)

·       Support – Not easily compressed (Turgid cells, amniotic sac, hydrostatic skeleton)

·       Amphoteric – Good buffer