what are enzymes?

• Why are enzymes important for living cells?

  They ease a huge number of chemical reactions every second.
• What is the problem with increasing the temperature to speed up chemical reactions?

  High temperatures can damage cells and speed up non-useful reactions.
• What is a catalyst?

  A catalyst is a substance that increases the speed of a chemical reaction without being changed or used up.
• How does a catalyst differ from an enzyme?

  An enzyme is a specific type of catalyst made by living organisms.
• What are enzymes made of?

  Enzymes are large proteins made up of long chains of amino acids.
• What determines the unique shape of an enzyme?

  The specific sequence of amino acids in the chain determines its shape.
• What is a substrate in the context of enzyme action?

  A substrate is a reactant that an enzyme acts upon in a chemical reaction.
• What is the role of the active site in an enzyme?

  The active site is a region of the enzyme that has a unique shape complementary to the substrate.
• What happens if a substrate does not fit the active site of an enzyme?

  The reaction will not be catalyzed if the substrate does not fit the active site.
• What are the two main models of enzyme action?

  • Lock and Key Model: Substrates fit perfectly into the active site.
  • Induced Fit Model: Enzyme changes shape slightly to fit the substrate better.
• How did the understanding of enzyme action evolve from the lock and key model to the induced fit model?

  Scientists now know that enzymes change shape slightly as they bind to substrates.
• How can you visualize the induced fit model of enzyme action?

  • Think of putting your hand into a rubber glove.
  • The glove molds around your hand to create a perfect fit.
• What is the significance of the active site being complementary to the substrates?

  It allows enzymes to be specific about which reactions they catalyze.