1.1 Water

Question 1

State 4 physiological roles of water based on their chemical properties

Answer 1

1) Water provides a medium for reactions to take place.
2) Acts as a solvent to transport substances
3) Ionises and acts as substrates for photolysis during photosynthesis and hydrolysis reactions.
4) Interacts with macromolecules such as protein and nucleic acids

Question 2

State the main physical properties of water

Answer 2

1) Has a high specific heat capacity.
2) High latent heat of vaporization
3) The density or specific gravity of water is highest at 4*C
4) High Cohesive force
5) High surface tension

Question 3

Explain high surface tension

Answer 3

-forms a strong inward pull of water forming a skin-like layer
- creates a habitat on the water’s surface
- allows insects to stay on the surface where they can gather food or catch their prey like water-skaters do

Question 4

Explain high cohesive force

Answer 4

-A high attractive force exists among water molecules due to the hydrogen bonds
- Tgt w adhesive force, water creates a transpirational pull in the xylem vessels when evaporation occurs in the leaves.
- Helps to transport water and mineral ions up the leaves of photosynthesis.