Properties

• Simply describe the 4 useful properties of water?

  • Important metabolite
  • High latent heat of vaporisation
  • Can buffer changes in temperature
  • Good solvent
• describe water being an important metabolite?

  • Many metabolic reactions involve a condensation or hydrolysis reaction
  • hydrolysis reactioons require molecules of water to break bonds
  • condensation reactions release a molecule of water as a new bond is formed
• give an example of a metabolic reaction involving condensation reactions?


  amino acids are joined together to make polypeptides/proteins by condensation reactions
• give an example of a metabolic reaction involving hydrolysis?

  energy from ATP is released through a hydrolysis reaction
• describe water having a high latent heat of vaporisation?

  • it takes lots of energy to break the hydrogen bonds between water molecules
  • so water has a high latent heat of vaporisation - lots of energy is used up when water evaporates/vaporises
• why is it useful for living organisms that water has a high latent heat of vaporisation?

  because it means they can use water loss through evaporation to COOL DOWN (eg humans sweat to cool down) WITHOUT LOSING TOO MUCH WATER
• what can water buffer?


  changes in temp
• what does buffer mean?


  resist
• what can the hydrogen bonds between watermolecules do

  absorb a lot of energy
• how can water buffer changes in temp?

  The hydrogen bonds between water molecules can absorb lots of energy.

  so water has a high specific heat capacity

  water does not experience rapid temp changes
• why is it useful to living organisms that water can buffer changes in temp

  water does not experience rapid temp changes = water is a good habitat because the temp under water is likely to be more stable than on land

  • WATER INSIDE ORGANISMS also remains fairly stable temp - helps them to maintain a constant internal body temp
• water is a good...

  solvent
• A lot of important substances in metabolic reactions are...


  ionic
• what does it mean if a substance is ionic


  they are made from one positively charged atom or molecule and one negatively charged atom/molecule
• water is polar- true or false


  true
• What is the effect of water being polar (context- water is a solvent)

  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

  • this means the ions will get totally surrounded by water molecules ie they will DISSOLVE
  • So water's polarity makes it a useful solvent
• whaty makes water a useful solvent

  water's polarity
• where is there strong cohesion between

  between water molecules
• what is cohesion

  the attraction between molecules of the same type
• why are water molecules very cohesive


  because they are polar
• water molecules are very cohesive- what does this mean?

  they tend to stick together
• what does strong cohesion help water to do?

  helps water to FLOW, making it great for transporting substances
• what does strong cohesion mean that water has?

  High surface tension when it comes into contact with air. this is the reason why sweat forms droplets which evaporate from the skin to cool an organism down
• Water is a metabolite in what?


  condensation

  hydrolysis

  photosynthesis

  respiration
• Water is a SOLVENT SO...?


  Metabolic reactions can occur
• Water is A SOLVENT SO...?


  allowing transport of substances
• water has a HIGH SPECIFIC HEAT CAPACITY SO?


  buffers changes in temperature
• Water has a large latent heat of vaporisation so....?


  provides a cooling effect through evaporation
• there is cohesion between water molecules so..?


  • supports columns of water in plants AND
  • produces surface tension supporting small organisms