Enzymes

• Enzymes = biological catalysts which speed up reactions
• catalyst = used over and over - not destroyed
• Enzymes break down large molecules into smaller molecules or join smaller molecules to make bigger ones
• An enzyme has an active site specifically shaped for its substrate
• A joined Enzyme and substrate = enzyme-substrate complex
• an enzyme-substrate complex produces products because the active site is no longer complimentary for the substrate
• Lock and key theory/model = an enzyme and substrate join, forming an enzyme-substrate complex, producing products
• Enzymes = proteins = long chains of amino acids
• An enzyme's amino acid chain sequence determines the shape and function of the enzyme
• Enzymes are specific so can only catalyse one type of reaction due to their specific shaped active site
• Factors that affect enzymes = temperature; pH; Enzyme concentration; substrate concentration
• best conditions for an enzyme = optimum condition
• increased temperature = more kinetic energy = Enzymes move faster = more chance of collision with substrate = faster rate of reaction
• When the temperature is too high, the rate of reaction decreases because the enzyme's active site denatures.
• denatures = enzyme's active site becomes misshaped, no longer complementary to substrate
• optimum pH = faster rate of reaction
• increasing the enzyme concentration = more enzymes to collide with substrate = higher chance of collision = faster rate of reaction
• increasing the substrate concentration = more substrates for enzymes to collide with = higher chance of collision = faster rate of reaction
• denatured = active site is no longer specifically shaped for substrate = no enzyme substrate-complexes form = reaction stops