enzymes

• Enzymes


  Protein molecules acting as biological catalysts that speed up chemical reactions
• Enzymes


  • Have a specific shape of active site
  • Active site is complementary to specific substrate
  • Fit together with substrate to form enzyme-substrate complex
  • Lower the activation energy of reactions
  • Catalyse the breakdown or building up of molecules
  • Work under optimum pH and temperature conditions
  • Product leaves the active site unchanged
• Enzyme catalysis


  1. Substrate binds to active site

  2. Enzyme-substrate complex forms

  3. Reaction is catalysed

  4. Product is released
• As temperature increases up to optimum


  Rate of enzyme-catalysed reaction increases gradually
• At optimum temperature


  Rate of enzyme-catalysed reaction is at a peak/maximum
• As temperature increases above optimum

  Rate of enzyme-catalysed reaction decreases steeply
• As pH increases towards optimum

  Rate of enzyme-catalysed reaction increases
• As pH moves away from optimum

  Rate of enzyme-catalysed reaction decreases
• Factors affecting enzyme activity include temperature, pH, substrate concentration, enzyme concentration, and surface area