3.1.7 Water Flashcards
Properties of water
- metabolite in metabolic reactions
- good solvent
- relatively high heat capacity
- relatively large latent heat of vaporisation
- strong cohesion between water molecules
Other important properties of water
- transparent to light
- less dense as a solid
Examples of metabolic reactions that water is a metabolite in
Condensation
Hydrolysis
Good solvent
Functions
└hydrophillic substances
└can become a part of waters hydrogen bonded structure -will dissolve in water
└e.g. ions, polar/charged molecules
└hydrophobic substances
└ cannot become a part of waters hydrogen bonded structure -wont dissolve in water
└e.g. nonpolar molecules
Solubility of gases
Makes aqueous solution
└increases rate of collisions between reactant molecules
Why is water a good solvent
Because it is polar
What does water do as a solvent?
- dissolves oxygen and carbon dioxide
- dissolve wastes such as ammonia and urea
- dissolve inorganic ions and small hydrophilic molecules such as amino acids, monosaccharides and ATP
- dissolves enzymes whose reactions take place in solution
Relatively high heat capacity
Definition
└water absorbs/loses a relatively large amount of heat before its temperature changes
└many stable hydrogen bonds between
molecules= lot of energy to break bonds
Relatively high heat capacity
Function
└buffers temperature changes
└is liquid over much of the globe,
└so can be habitat, solvent, reactant etc;
└provides suitable medium for enzymes;
Relatively large latent heat of vaporisation
Definition
└water absorbs a large amount of energy before it turns into water vapour
Relatively large latent heat of vaporisation
Function
Provides a cooling effect with little loss of water through evaporation
cohesion
attraction between particles of the same substance
adhesion
attraction between particles of different substances
water = strong adhesive properties
- causes capillary action in e.g. paper towel, xylem or plants
- because polar
Strong cohesion between water molecules
Function
- allows unbroken columns of water to rise up the xylem as a result of transpiration
- produces surface tension where water meets air
water = less dense as a solid
Ice is less dense than water= floats
└forms an insulating layer so water below doesn’t freeze
└organisms survive beneath insulating layer
└currents= nutrients circulate
