How to Revise Enzymes — OCR A-Level Biology
Enzymes is a topic in the OCR A-Level Biology specification. This guide covers learning objectives, examiner tips, common mistakes, and key terminology to help you revise effectively.
Examiner Tips for Enzymes
- Always refer to the tertiary structure of the enzyme when discussing denaturation
- When describing enzyme-substrate binding, use the term 'complementary' to describe the active site and substrate
- Ensure units are included in all rate calculations
- Be prepared to interpret graphs showing the effect of inhibitors on reaction rate
- Remember that enzymes are proteins and their function is dependent on their specific 3D shape
Common Mistakes in Enzymes
- Confusing competitive and non-competitive inhibition mechanisms
- Failing to mention the lowering of activation energy when describing enzyme function
- Incorrectly describing the effect of temperature on enzymes (e.g., ignoring denaturation)
- Misinterpreting Q10 calculations
- Confusing intracellular and extracellular enzyme examples
Key Marking Points
- Role of enzymes in catalysing intracellular and extracellular reactions
- Tertiary structure and specificity of the active site
- Lock and key vs induced-fit hypotheses
- Formation of enzyme-substrate and enzyme-product complexes
- Lowering of activation energy
- Effects of pH, temperature, enzyme concentration, and substrate concentration on rate