Water

• Features of water:

  • Its a polar molecule
  • It is a metabolite in metabolic reactions such as condensation and hydrolysis
  • High specific heat capacity
  • Maximum density of water is at 4 degrees
• What solvents can dissolve in water?

  • Charged or polar molecules such as salts,sugars and amino acids dissolve readily in water
  • Uncharged or non polar molecules such as lipids dont dissolve so well in water
• What is cohesion?

  Forces of attraction between molecules of the same type
• What is adhesion?

  • Forces of attraction between water and another molecule
• How are insects able to walk on water?

  • Molecules at the surface are only attracted to neighboring molecules below and to the sides but not above- creating an imbalance
  • These unbalanced force at surface create a net inward force pulling surface molecules closer together
  • This makes the surface more resistant to external forces and giving a rise to surface tension
• Why is it beneficial that water has a high latent heat of evaporation/ vaporation?

  • When water evaporates from a surface it absorbs head from its surrounding
  • If an increase in body temperature id detected the body responds by increasing the secretion of heat
  • A lot of heat energy has to be transferred from body to break the hydrogen bonds between the h20 molecules
• How is a high specific heat capacity of water benefitial?

  • Water is thermostable
  • When water loses heat energy it releases energy first by forming hydrogen bonds and the decreasing the KE of the molecules resulting in slower decrease in temp
  • As water holds a lot of of energy from absorption and holds a stable temp for enzyme- controlled reactions to happen properly
• How is water having a less density when solid beneficial?

  • When water freezes the water molecules are held further apart in ice than they are in liquid water
  • Water molecules forms four hydrogen bonds to other water molecules- making a lattice shape
  • This means aquatic organisms have a stable environment in which to live throughout winter, where they can still move
  • The pond is insulated against extreme as ice layer reduces heat loss
• What chemical reactions does water take place in?

  • Photosynthesis
  • Respiration
• How is water involved in hydrolysis reactions?

  Breaks a chemical bond between the two molecules and involves the use of water molecule
• How is water involved in condensation reactions?

  • Joins two molecules together with the formation of a chemical bond
  • Involves the elimination of a molecules of water
• How is water transparent?

  • Light can penetrate water allowing aquatic photosynthesis plants
  • Shallow fish have good vision
• Why is water incompressible?

  • Hydrostatic skeleton