Water

Question 1

How is water described

Answer 1

Polar molecule (due to unequal sharing of electrons)

Question 2

What bonds water molecules together

Answer 2

Hydrogen bonds which are weak but collectively strong

Question 3

Properties of water

Answer 3

1. Metabolite
2. Solvent properties
3. High specific heat capacity
4. High latent heat of vapourization
5. Cohesion and adhesion
6. Density and freezing

Question 4

Water as a metabolite

Answer 4

= a substance made or used when the body breaks food, drugs or chemicals
Chemical reactions take place in an aqueous medium - raw material for photosynthesis

Question 5

Water solvent properties

Answer 5

Acts as a transport medium for dissolved substances- poor solvent for non-ionic, non-polar compounds as is polar

Question 6

Water has high specific heat capacity

Answer 6

Can absorb large amounts of heat energy before its temp raises a significant amount - this allows organism to survive without experiencing wide temp fluctuation + highly regulated internal body temp

Question 7

Water has high latent heat of vaporisation

Answer 7

Amount of energy needed to vaporise 1g of water - allows mammals to cool down (due to sweating) as heat is used to evaporate the water

Question 8

Water - adhesion and cohesion

Answer 8

Cohesion = tendency of molecules to stick to each other
Adhesion = tendency of molecules to stick to something else
Allows surface tension and it to be pulled in a tube eg a xylem vessel

Question 9

Water density and freezing

Answer 9

Water at ordinary temp Inc in density as it is cooled until 4 degrees c where max density is reached and then it decreases in density allows things to live at bottom of lake etc when it freezes

Question 10

Inorganic ions

Answer 10

Occur in solution in cytoplasm e,g
- iron in hb
- phosphate in dna
- hydrogen to determine ph of sol
- sodium ions for transporting glucose across plasma membranes