2.4 - Water and it’s functions

• What’s a major component of cells ?


  Water
• Why is water described as dipolar ?


  Oxygen atom has a slightly negative charge and the hydrogen has slightly positive
• What is a metabolite ?


  A substance needed for metabolic reactions
• What 2 reactions is water a key component of ?


  Condensation and hydrolysis
• What bonds hold water molecules together ?


  Hydrogen bonds between the negative and positive poles
• What kind of specific heat capacity does water have and what does it mean ?


  A high one, takes lots of energy to raise the temp by 1 degree
• What does the high heat capacity of water allow organisms to do ?


  Buffer temperature changes and maintain 37 degrees
• Why does water have a high heat capacity ?


  The molecules are stuck together so takes more energy to separate them
• What kind of latent heat does water have ?


  A high one
• What does the large LHofV of water provide for an organism ?


  Provides a cooling effect with little loss of water through evaporation
• What’s cohesion and why does it occur ?


  Water molecules are all attached to each other and all move together due to hydrogen bonds
• Why is cohesion important in plants ?


  Supports columns of water in the xylem vessel of plants, allows water to be transported around a plant
• What can cohesion cause in water ?


  Surface tension where water meets air
• Why is water a solvent ?


  It readily dissolves other substances
• Why is water an important solvent ?


  Many metabolic reactions occur in it
• 4 substances that water dissolves and examples of them ?

  gases (O2 and CO2), waste (urea and ammonia), inorganic ions and small hydrophilic molecules (amino acids, monosaccharides and ATP, enzymes
• Where do inorganic ions occur ?


  In solution in the cytoplasm and body fluids of organisms
• What does an ions specific role depend on ?


  It’s properties