Enzymes

• What is the protein structure of enzymes?


  Tertiary protein structure joined together by ionic bonds, hydrogen bonds, and disulfide bridges

  They are also globular proteins - chains of amino acids joined together by peptide bonds
• How do enzymes speed up chemical reactions?

  They are biological catalysts, and they lower the activation energy, which increases rate of reaction
• What is metabolism?

  The sum of all chemical reactions an organism needs to survive
• What are intracellular enzymes?

  Enzymes that are made in the cell and work inside the cell - needed for cell metabolism
• What are extracellular enzymes?

  Enzymes that work outside the cell that made them, and become functional in conditions outside the cell
• Describe the lock and key model:

  • Active site + substrate 100% complementary and a precise fit
  • Active site doesn't change shape
• Describe the induced fit model:

  • Active site + substrate not completely complementary
  • Active site changes shape to mold itself against substrate, as its flexible due to its globular structure, and forms enzyme-substrate complexes
  • This puts strain on bonds in substrate and breaks them
• What is denaturation?

  • When active site changes shape due to extreme pH/temperature, and can no longer fit a substrate
  • Bonds are broken in the tertiary structure - irreversible