Water

Water (H2O) is an abundant and essential molecule in biological systems, often referred to as the ‘solvent of life.’
It is a polar molecule, with the oxygen atom being slightly negative and the hydrogen atoms being slightly positive, allowing it to form hydrogen bonds with other molecules.

Hydrogen bonds between water molecules contribute to its unique properties beneficial to life.
Water’s high specific heat capacity ensures that it can absorb and release large amounts of heat before changing temperature, providing a stable environment for organisms.
Its high latent heat of evaporation provides an effective cooling mechanism via sweating or evaporation from leaves (transpiration) in plants.
Water’s cohesion and adhesion properties contribute to capillary action, which helps water transport against gravity in plants.

The polarity of water makes it an excellent solvent where many compounds, including salts, sugars, gases, and other polar molecules, dissolve.
This solubility allows biological reactions to occur in an aqueous environment and aids in transportation of substances in organisms.

When frozen, water forms a structured lattice held together by hydrogen bonds, which makes ice less dense than liquid water, allowing it to float.
This feature provides an insulating layer on water bodies during the cold weather, protecting aquatic life underneath.

Water’s involvement in hydrolysis and condensation reactions are important for building and breaking down molecules in biological systems.
Cell turgidity, which helps to give plants their shape, is due to water pressure within cell walls, demonstrating water’s role in supporting structures.
In osmosis, water moves across a semipermeable membrane from areas of low solute concentration to high solute concentration.
The small size of water molecules allows them to hydrate ions, aiding in various cellular processes such as enzyme activities and nerve impulse transmission.