WATER AND ITS FUNCTIONS

Question 1

What are the unusual properties due to

Answer 1

the dipolar nature

Question 2

Why is water dipolar

Answer 2

oxygen atom has a slight negative charge, hydrogen atoms have a slight positive charge

Question 3

What 5 main functions does water have

Answer 3

1) metabolite
2) solvent
3) temperature control
4) support
5) transport

Question 4

Why is water an important metabolite

Answer 4

hydrolysis & condensation reactions require a water molecule

Question 5

Why is water a good solvent

Answer 5

due to being polar, one end is attracted to the negative ion and one end is attracted to the positive ion so water surrounds molecules (dissolves them)

Question 6

What 4 substances does water readily dissolve

Answer 6

1) gases (0 & C02)
2) wastes (ammonia and urea)
3) inorganic ions and small hydrophilic molecules (amino acids, monosaccharides, ATP)
4) enzymes whose reactions take place in a solution

Question 7

Why is water good at temperature control (2 reasons)

Answer 7

1) it has a high latent heat of vaporisation, so takes a lot of energy to break the hydrogen bonds between water molecules and therefore uses lots of energy when it evaporates = cools surface down when it evaporates
2) can buffer changes in temperature as hydrogen bonds can absorb a lot of energy so has high specific heat capacity so doesn’t experience rapid temperature changes

Question 8

Why is water good for support

Answer 8

not easily compressed

Question 9

Why is water good for transport

Answer 9

there is a strong cohesion between water molecules because they’re polar, so it can flow
e.g. water transport in xylem of plants

Question 10

What else does the strong cohesion of water mean

Answer 10

it has a high surface tension and can form droplets