Water

• Water has a high specific heat capacity, which means it can absorb and retain a large amount of heat without a significant change in temperature.
• The structure and properties of water relate to its role as a medium of life.
• Water has solvent properties and essential roles in transport at both the cellular and systemic levels.
• Water is the most important biochemical and the most abundant liquid on earth.
• Water stress is a problem in the environment and constituent.
• Water is the basis of transport systems and an essential solvent.
• Water is a critical medium of life.
• Water has high transmission of visible light energy and is essential for photosynthesis.
• Water supports a significant structural role as a hydrostatic skeleton, penile erection, eye humours, turgidity in plants, and amniotic fluid.
• Water is colourless/transparent, allowing light energy to penetrate and photosynthesis to occur at depth.
• Water is sticky, as evidenced by the detergent coin challenge.
• Ascending trees illustrates both cohesion, the attraction between different molecules, and adhesion, the attraction between similar molecules.
• Mass flow is the movement of a large body of water in one direction without breaking apart.
• The deceptively simple water molecule consists of 1 oxygen atom that combines with 2 hydrogen atoms by sharing electrons (covalent bond).
• The polar molecule is non-linear and V-shaped, with more electronegative oxygen nucleus drawing electrons away from hydrogen nucleus.
• The unequal distribution of charge within the water molecule results in it being polar but electrically neutral overall.
• The water molecule has an irregular shape, with one end being slightly positive (hydrophilic) and the other end being slightly negative (hydrophobic).
• Chemical (metabolic) reactions in solution are facilitated by water.
• Hydrophobic molecules are non-polar, do not form hydrogen bonds, and are repelled by water and pushed together in hydrophobic interactions.
• Water is a critical medium of life, providing the environment (habitat) to live in and making up a large part of cells/bodies (constituent).
• Water has relative stability of temperature of bodies of water, high specific heat capacity, and a cooling effect of evaporation.
• Water is the basis of transport, moving through plasma, lymph, and phloem sap, which includes dissolved gases and is crucial for aquatic organisms.
• Water moving up the xylem is cohesive, with high tensile strength, enabling mass flow to the heights.
• The clarity of seawater is important because light energy can penetrate, allowing photosynthesis to occur at depth and enabling animals to see prey and predators.
• Water has a high latent heat of vaporisation, making sweating and transpiration key to temperature control.
• Water is the key to waste removal and secretions.
• Glucose being moved around the body requires water as a universal solvent, permitting easy transport of substances.
• Hydrogen bonds form due to electrostatic attraction between slightly positively charged region of one water molecule (electropositive hydrogen) and slightly negatively charged region (electronegative oxygen) of a neighbouring water molecule.
• Clustering effect of hydrogen bonds makes water 'sticky'.
• Water sticks/adheres to polar surfaces, acting as a molecular glue.
• If adhesive forces are greater than cohesive forces, water wets.
• Weak, inter-molecular forces or interactions occur whenever molecules have a slightly negatively charged atom bonded to a slightly positively charged hydrogen atom (electropositive).
• Hydrogen bonds are individually weak but collectively strong.
• Water participates in chemical reactions.
• Cohesion explains continuous columns of water that do not break easily under tension, mass flow (movement of large body of water in one direction without breaking apart), and high surface tension.
• The weak electrostatic force of attraction between hydrogen and electronegative atoms is responsible for the adhesion of water to polar surfaces.
• Water has relatively low viscosity, allowing for low force for movement of aquatic animals and streamlined shape.
• Hydrogen bonds are impermanent but highly significant.
• Hydrogen bonds allow water to cohere and adhere.
• Cohesive forces between molecules at surface cause the surface to behave like a stretched membrane, able to withstand considerable force without breaking.