water
water is a polar molecule:
-this polarity gives it special properties
-solid ice is less dense than liquid water
-this makes it float
-dipolar slightly +ve and -ve
-the O has more pull than the H2 so it makes it polar
-its dipolarity make it able to form Hbonds
high specific heat capacity:
-a lot of energy is needed to raise the temp of H2O due to many Hbonds
-importance:
-maintains a relatively constant temp
-less temp change in aquatic environments
-as organisms are mostly H2O terrestrial organisms are also protected from sudden temp change
cohesion:
-sticking together of H2O molecules due to Hbonds
-allows a column of H2O to be moved through a tube
surface tension:
-Hbonds can form a film on the waters surface
-can support small organisms
latent heat of vaporisation:
-the energy required to change a substance into a gas
-H2O as a coolant
for metabolic reactions:
-breaking down complex molecules via hydrolysis
-take place in an aqueous medium
-in photosynthesis
as a solvent:
-most substances dissolve in H2O
-non-polar molecules will not dissolve
-importance:
-blood plasma will dissolve substances in it
-cytoplasm contain high % of H2O
-plants use it to transport ions
transparent:
-light can penetrate ocean surfaces for photosynthesis
-light can pass through jelly like substance in eyes to reach the retina
not easily compressed:
-for maintaining shape and structure
-hydrostatic earthworm skeleton
-turgor pressure in plants