3. Water Flashcards
importance of water in living organisms
- a metabolite in lots of important metabolic reactions e.g. condensation and hydrolysis
- solvent - some substances dissolve in it. most metabolic reactions take place in solution
- temperature control. high latent heat of vaporisation ad high specific heat capacity
- cohesive - helps water transport in plants
water is an important metabolite
many metabolic reactions involve condensation / hydrolysis reaction
hydrolysis requires water to break a bond
condensation reaction releases water to make a bond
e.g. amino acids joined to make polypeptides via condensation reaction
energy from ATP released by hydrolysis
water has a high latent heat of vaporization
why?
useful for living organisms?
lots of energy to break h bonds = high latent heat of vaporisation (lots of energy used when water evaporates
can use water loss through evaporation to cool down without loosing too much water
e.g. humans sweat
water can buffer (resist) changes in temp
- why?
- useful for living organisms?
1.H bonds can absorb a lot of energy = high specific heat capacity
2. doesn’t experience rapid temperature change
good habitat temp in water more stable than land
water inside organisms stable temp helping maintain constant internal body temperature
water is a good solvent
1. why?
lots of importance substances in metabolic reactions are ionic
water is polar -
+ end attracted to negative ion
- end attracted to a positive ion
ions surrounded by water molecules = dissolve
strong cohesion (attraction) between water molecules
- why?
- useful for living organisms?
- they’re polar
- helps water flow. good for transporting substances e.g. water travels in colums up xylem in plants
high surface tension when it comes into contact with air = sweat forms droplet which evaporate from skin to cool organism down
pond skaters and some other insects can ‘walk’ on surface of pond