1.7 Water

Question 1

What is water a major component of?

Answer 1

cells

Question 2

Explain how hydrogen bonds occur between water molecules

Answer 2

● Water is polar molecule

● Slightly negatively charged oxygen atoms attract slightly positively charged hydrogen atoms of other water molecules

Question 3

What is the importance of water being a metabolite?

Answer 3

Used in condensation / hydrolysis / photosynthesis / respiration

Question 4

What is the importance of water being a solvent?

Answer 4

1. Allows metabolic reactions to occur (faster in solution)
2. Allows transport of substances eg. nitrates in xylem, urea in blood

Question 5

What is the importance of water having a high specific heat capacity?

Answer 5

● Buffers changes in temperature

● As can gain / lose a lot of heat / energy without
changing temperature

1. Good habitat for aquatic organisms as temperature more stable than land
2. Helps organisms maintain a constant internal body temperature

Question 6

What is the importance of water having a large latent heat of vaporisation?

Answer 6

● Allows effective cooling via evaporation of a small volume (eg. sweat)

● So helps organisms maintain a constant internal body temperature

Question 7

What is the importance of water having strong cohesion between water molecules?

Answer 7

1. Supports columns of water in tube-like transport cells of plants eg. transpiration stream through xylem in plants
2. Produces surface tension where water meets air, supporting small organisms (to walk on water)