A-Level Biology AQA Notes

3.1.4.2 Many proteins are enzymes

Enzymes
  • Enzymes are biological catalysts that speeds up the rate of reaction and remains unchanged and reusable at the end of the reaction.
  • They lower the activation energy of the reaction.
  • ​The lock and key model proposed that each substrate is a key that only fits a specific lock or enzyme. The alternative induced fit model has been proposed (below)
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  • The specificity of enzymes is due to the tertiary structure of its active site, allowing complementary binding to substrates.
  • Enzymes catalyse both intracellular and extracellular reactions that determine structures and functions from cellular to whole organism level.
  • Factors affecting enzyme activity include:
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