Enzymes

• What is metabolism?


  All the chemical processes that occur within a living organism to maintain life.
• What is catabolism?


  The breakdown of larger molecules into smaller ones.
• What is anabolism?


  The buildup of larger molecules from smaller molecules.
• Why are catalysts important in chemical reactions?

  They speed up the rate of chemical reactions, preventing them from being too slow.
• What is a catalyst?


  A substance capable of speeding up the rate of a chemical reaction and is unchanged by the reaction.
• What are enzymes?


  Proteins that function as biological catalysts to increase the rate of chemical reactions.

  
• How do enzymes affect chemical reactions?

  They increase the rate at which chemical reactions occur without being changed at the end of the reaction.

  
• What are the properties of enzymes?

  1. They are proteins (macromolecules).
  2. They are biological catalysts that increase the rate of a reaction.
  3. They are specific; only molecules with a complementary shape can fit into the enzyme (lock and key model).
  4. They are affected by temperature and pH.
  5. They are required in small amounts.
  6. They are reusable.

  
• What is the active site of an enzyme?

  The 'dent' on the enzyme which is exactly the correct shape for the substrate to fit into.

  
• What happens if a molecule does not fit into the enzyme's active site?

  No reaction will occur.
• What is the enzyme-substrate complex (ESC)?

  The substrate bonds with the enzyme's active site, forming an enzyme-substrate complex.

  
• What are the products of the enzyme trypsin acting on polypeptides?

  Amino acids.

  
• What does sucrase act on and what are its products?

  It acts on sucrose to produce glucose and fructose.
• What does maltase act on and what are its products?

  It acts on maltose to produce glucose and glucose.
• What does lipase act on and what are its products?

  It acts on lipids (fats and oils) to produce fatty acids and glycerol.

  
• What does pepsin act on and what are its products?

  It acts on proteins to produce polypeptides.
• What does amylase act on and what are its products?

  It acts on starch to produce maltose.

  
• What does lactase act on and what are its products?


  It acts on lactose to produce galactose and glucose.

  
• What does catalase act on and what are its products?

  It acts on hydrogen peroxide to produce oxygen and water.

  
• What factors influence the rate of chemical reactions?

  • Temperature
  • pH (amount of free hydrogen ions in a solution)

  
• What is the optimum temperature for an enzyme?

  The temperature at which the rate of enzyme activity is greatest.

  
• How does temperature affect enzyme activity?

  As temperature increases, the rate of enzyme activity also increases until an optimum temperature is reached.

  
• What happens to enzyme activity at higher temperatures?

  Too much kinetic energy can cause the enzyme to vibrate too much, breaking bonds and changing the structure of the enzyme.

  
• What is denaturation in enzymes?

  It is a permanent change where the enzyme's active site changes shape, preventing substrate binding.

  
• What happens to enzyme activity at lower temperatures?

  The rate of enzyme activity is very slow, and enzymes become inactive at very low temperatures.

  
• What is the effect of pH on enzyme activity?

  Each enzyme has a pH at which the rate of reaction is greatest, known as the optimum pH.

  
• What happens to enzymes at extreme pH levels?

  Extreme pH levels can denature enzymes irreversibly.

  
• What is the optimum pH for amylase?

  pH 7 to 7.5, where it digests starch into maltose.

  
• What is the optimum pH for pepsin?

  pH 2 to 3, where it digests proteins into polypeptides.

  
• What is the optimum pH for lipase?

  pH 9, where it digests lipids into glycerol and fatty acids.