Monomers and polymers + water

• Condensation reaction


  The chemical reaction that combines biological monomers
• Condensation reaction


  • A new covalent bond is formed
  • A water molecule is released
  • A larger molecule is formed by joining smaller molecules
• Hydrolysis reaction


  Splitting larger molecules to smaller ones - the reverse of a condensation reaction
• Hydrolysis reaction


  • A covalent bond is broken
  • A molecule of water is used
  • Smaller molecules are formed
• Polymers are made from monomer units joined together by covalent bonds.
• Metabolite


  Many metabolic reactions require them to bind disaccharides to monosaccharides by hydrolysis reactions e.g photosynthesis respiration and condensation
• High Latent heat of Vaporisation


  The evaporation of water requires a lot of energy to break the hydrogen bonds. When water evaporates from a surface it 'removes' the heat and has a cooling effect e.g. sweating and transpiration
• Low density of ice

  As the water is cooled and the molecules slow down, more hydrogen bonds form holding the water molecules to form a crystalline structure which is less dense than liquid water. This means that ice floats on water and insulates the organisms that live beneath it
• High Specific Heat Capacity

  Thermostability the hydrogen bonds in water prevent the movement of the water molecules so relatively large amounts of energy are required to increase the temperature of water (it buffers change in temperature
• Cohesion


  Hydrogen bonds cause water molecules to stick together. This results in surface tension at the surface of water. This can allow some organisms to 'walk on water' e.g. pond skaters
• Solvent


  The polarity of water allows it to be a really good solvent. Any polar molecules like ions will dissolve well in water. The negative ions will be attracted to the positive end of the water molecule and the positive ions to the negative end. Water molecules tend to cluster around any charged parts of solute molecules. This allows metabolic reactions such as photosynthesis and respiration to take place in solution in the cytoplasm
• Transport Medium


  Since water is a good solvent and remains liquid over a wide range of temperatures means that water is a good transport medium e.g. plasma in blood, mineral ions in the xylem
• Transparent


  As water is transparent, aquatic organisms, such as algae and seaweed, are able to photosynthesise as the sunlight passes through the water