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2015-01-05 10:14:37

Biology A Level Unit 1
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  1. What are enzymes?
    Catalysts that lower the activation energy, through formation of enzyme-substrate complexes
  2. Describe the Lock and Key mechanism?
    The active site of the enzyme is a rigid structure and a specific shape, only certain substrates which fit that exact shape can fit and form a enzyme-substrate complex. Like how only certain keys fit certain locks
  3. Describe the induced fit model?
    The active site isnt a rigid structure, and instead changes shape to fit the substrate forming a enzyme-substrate complex
  4. How is the activation energy lowered in the induced fit model?
    The shaping of the active site applies pressure on the substrate molecule, which distorts bonds and consequently lowers the activation energy needed to break the bond
  5. How does temperature effect enzymes?
    • Kinetic energy increases, more enzymes colliding with substrate molecules, rate of reaction increases
    • It drops if temperature too high, hydrogen bonds break and enzyme shape changes to rate of reaction decreases
  6. How does pH effect enzymes?
    • pH alters the change on amino acids in enzymes which make up the active site, therefore changes shape and substrate can't fit so rate of reaction decreases
    • Can cause hydrogen bonds of tertiary structure to break, change shape etc
  7. How does substrate concentration effect enzymes?
    Higher concentration means more enzyme-substrate complexes so faster rate of reaction