Water

• Explain how hydrogen bonds occur between water molecules

  • Water is a polar molecule
  • Slightly negatively charged oxygen atoms attract slightly positively charged hydrogen atoms of other water molecules
• Why is water being a metabolite important?

  Water is used in condensation/hydrolysis/respiration/photosynthesis reactions
• Why is water being a solvent important?

  • Allows metabolic reactions to occur (faster in solution)
  • Allows transport of substances e.g. nitrates in xylem, urea in blood
• Why is water having a high specific heat capacity important?

  • Buffers change in temperature
  • As can gain/lose a lot of heat/energy without changing temperature

  1. Good habitat for aquatic organisms as temperature more stable than land
  2. Helps organisms maintain a constant internal body temperature
• Why is water having a high latent heat of vaporisation important?

  • Allows effective cooling via evaporation of a small volume e.g. sweat
  • So helps organisms maintain a constant internal body temperature
• Why is water having string cohesion between water molecules important?

  1. Supports columns of water e.g. transpiration stream through xylem
  2. Produces surface tension, supporting small organisms (walk on water)