3.1.7 - WATER

Question 1

explain five properties that make water important for organisms (5)

Answer 1

1. a metabolite in condensation/hydrolysis reactions
2. a solvent so metabolic reactions can occur/allowing transport of substances
3. high specific heat capacity so buffers changes in temperature
4. large latent heat of vaporisation so provides a cooling effect through evaporation
5. cohesion between water molecules so supports continuous columns of water in plants
6. cohesion between water molecules so produces surface tension supporting small organisms

Question 2

state and explain the property of water that helps to prevent temperature increase in a cell (2)

Answer 2

1. high specific heat capacity
2. buffers changes in temperature

Question 3

state and explain the property of water that can help to buffer changes in temperature (2)

Answer 3

1. relatively high specific heat capacity
2. takes a lot of heat/energy to change temperature

Question 4

give two properties of water that are important in the cytoplasm of cells. for each property, explain its importance in the cytoplasm (4)

Answer 4

ANY TWO PAIRS:

1. polar molecule
2. acts as a universal solvent

OR

1. universal solvent
2. metabolic reactions occur faster in solution

OR

1. reactive
2. takes place in hydrolysis/condensation

Question 5

give three properties of water that are important in biology (3)

Answer 5

any three:

1. is a metabolite
2. is a solvent
3. high heat capacity
4. large latent heat of vaporisation
5. has cohesion/hydrogen bonds between molecules