Water

Question 1

Why is water a polar molecule?

Answer 1

Due to the uneven distribution of charge within the molecule - the H atoms are more positive than the oxygen atoms - as a result H bonding between. many water molecules can occur allowing them to stick together

Question 2

What is water in metabolic reactions?

Answer 2

A metabolite such as in condensation and hydrolysis reactions which are used in forming and breaking of chemical bonds

Question 3

What does water being a solvent allow it to do?

Answer 3

Allows gases to readily diffuse as well as enzymes and waste products, e.g. ammonia and urea

Question 4

Why does water have a high heat specific capacity?

Answer 4

• water molecules stick together with hydrogen bonds meaning that a lot of energy is required to break these bonds
• helps to minimise temperature fluctuations in living things, acts as a buffer

Question 5

What do the hydrogen bonds in water do?

Answer 5

• A lot of energy is required to break 1 gram of water
  -water has a relatively large latent heat of vaporisation, meaning evaporation of water provides a cooling effect with little water loss, e.g. sweating

Question 6

What does strong cohesion between water molecules mean?

Answer 6

-enables effective transport of water in tubes, e.g. xylem
-strong cohesion supports columns of water, resulting in high surface tension at the water-air boundary