How to Revise Biological Molecules — Pearson A-Level Biology
Describe the structure of a water molecule. Explain the properties of water that make it essential for life
Examiner Tips for Biological Molecules
- Draw diagrams to illustrate hydrogen bonding.
- Use mnemonics to remember properties.
- Practice explaining how each property supports life.
- Draw simple diagrams to illustrate each level.
- Use examples like haemoglobin for quaternary structure.
- Explain how mutations can alter protein function.
- Draw and label the lock-and-key model clearly.
- Practice plotting and explaining enzyme rate graphs.
Common Mistakes in Biological Molecules
- Confusing cohesion with adhesion.
- Forgetting that water is a polar molecule.
- Not linking properties to biological functions.
- Confusing secondary and tertiary structure.
- Omitting the role of hydrogen bonds in secondary structure.
- Failing to link structure to specific functions like enzyme activity.
Key Marking Points
- Describe the structure of a water molecule, including polarity.
- Explain how hydrogen bonds form between water molecules.
- List properties of water: cohesion, adhesion, high specific heat capacity, etc.
- Relate water's properties to its role in living organisms.
- Explain why water is a universal solvent.
- Describes primary structure as amino acid sequence.