Water and its Functions Flashcards
why is water described as dipolar?
because the oxygen atom has a slight negative charge, while the hydrogen atoms have a slight positive one, therefore it has both positive and negative poles
how do water molecules bond?
the positive pole of one water molecule is attracted to the negative pole of another water molecule. the attractive force between these forces is called a hydrogen bond
why does water have a high boiling point
because water molecules stick together, it takes more energy to separate them than would be needed if they did not bond to one another
whats good about water having a high specific heat capacity
it can act has a buffer against sudden temperature variations, making the aquatic environment a temperature stable one.
the water inside organisms also remains at a fairly stable temperature, helping them to maintain a constant internal body temperature
why does it take a lot of energy to to evaporate water
the hydrogen bonding between the water molecules, this energy is called the latent heat of vaporisation, so water has a high latent of vaporisation.
why is water having a high latent of vaporisation useful for living organisms?
as it means they can use water loss through evaporation to cool down (humans sweat ti cool down) without loosing too much water
what is cohesion?
the tendency of molecules to stick together
what does the large cohesive forces in water allow it to do?
with its hydrogen bonding, the large cohesive forces allow it to be pulled through a tube such as a xylem vessel in plants
what does a strong cohesion in water also mean it will have?
a high surface tension
what does a high surface tension in water mean. give an example
when water molecules meet the air they tend to be pulled back into the body of water rather then escaping from it
it allows pond skaters to walk on it
what percent water are mammals and why is water important to living organisms
mammals are typically 65% water
it is the environment where many species live
why is water important in metabolite
hydrolysis requires a water molecule and condensation reactions produce a water molecule
chemical reactions take place in an aqueous medium
water is a raw material in photosynthesis
why is water a good solvent and give an example of what is readily dissolves
because water is polar, the positive end of a water molecule will be attracted to the negative ion, and the negative end of a water molecule will be attracted to the positive ion
gases such as oxygen and carbon dioxide
what are some other important features of water
its evaporation cools organisms and allows them to control their temperature
it is not easily compressed and therefore provides support
it is transparent and therefore aquatic plants can photosynthesise
what is an ion
an atom that has an electrical charge
