1.7 Water ( biological molcules )

Question 1

explain how hydrogen bonds occur between water molecules

Answer 1

• water is polar molecule
• slightly negatively charged oxygen atoms attract slightly positively charged hydrogen atoms of other water molecules

Question 2

Explain 5 properties of water that are important in biology

Answer 2

Metabolite :
• used in condensation / hydrolysis / photosynthesis/ respiration
Solvent :
• allows metabolic reactions to occur
• allows transport of substances
High specific heat capacity :
• buffers changes in temp
• as can gain / lose a lot of energy without changing temp
- good habitat for aquatic organisms as temp more stable than land
- helps organisms maintain a constant internal body temp
Large latent heat of vaporisation :
• allows effective cooling via evaporation of a small volume
• so helps organisms maintain a constant internal body temperature
Strong cohesion between water molecules
• supports columns of water in tube like transport cells of plants e.g transpiration stream
• produces surface tension where water meets air , supporting small organisms