Principles Module 11


  • Describe what an enzyme is and what it does
  • Discuss the ways enzymes are regulated
  • Explain the kinds of enzyme inhibition and example scenarios

Key points

  • enzymes speed up reactions that would happen anyway
  • terminology: substrate, product, naming, active site
  • enzymes lower the activation energy of a reaction by making more stable transition states
    • bring substrates together in correct orientation
    • placing bond-angle stress on reactive group
    • facilitating oxidation or reduction of substrate
  • enzymes are not permanently changed by reactions, cycle and reused
  • very highly specific for substrates
  • regulation of enzymes by feedback inhibition
    • competitive inhibitors bind to active site
    • allosteric inhibitors bind to other site and change active site

In-class activities

Read the article New Enzymes Created For Biofuel Production and respond to the following questions:

  • What reaction did the newly-invented enzymes catalyze? Be specific and use chemical terms and structures.
  • What are some sources of cellulose, and why is it preferrable to starch as a starting material for biofuel?
  • How did the researchers ‘create’ these new enzymes?
  • In what ways do you think the new enzymes differ from the natural ones?
  • Name some of the properties of the new enzymes compared to the natural ones.