Enzymes

• What are enzymes classified as?

  Biological catalysts
• What is the primary function of enzymes?

  To enable chemical reactions to take place faster
• How do enzymes behave in chemical reactions?

  They are not used up in chemical reactions
• What is the structure of enzymes?

  Enzymes are globular proteins with a specific shape
• What are the two types of reactions enzymes can catalyze?

  • Breaking down reactions (hydrolysis)
  • Building up reactions (condensation)
• What is the product of the hydrolysis of starch?

  Maltose
• What enzyme is responsible for breaking down starch?

  Amylase
• What is the product of the condensation of glucose and glucose?

  Maltose
• What is the product of the condensation reaction involving maltose?

  Sucrose
• What is the primary structure of enzymes made of?

  • Many amino acids joined together
  • Formed by peptide bonds
  • Created via condensation reactions
• How is the tertiary structure of enzymes formed?

  • Primary structure folds into secondary structure
  • Secondary structure folds into specific tertiary structure
• What is the significance of the active site in enzymes?

  It has a specific shape that is complementary to only one substrate
• What are the two theories explaining enzyme specificity?

  • Lock and Key Theory
  • Induced Fit Theory
• What does the Lock and Key Theory state about enzyme action?

  The active site has a fixed shape complementary to the substrate
• How does the Induced Fit Theory differ from the Lock and Key Theory?

  The active site changes shape to become complementary to the substrate
• How does protease hydrolyze proteins?

  It binds to proteins forming an enzyme-substrate complex and hydrolyzes peptide bonds
• What determines the different tertiary structures and active site shapes of enzymes?

  • Different amino acid sequences
  • Folding of primary structure into secondary and tertiary structures
• How does temperature affect the rate of enzyme reactions?

  As temperature increases, the rate of reaction increases until the optimum temperature
• What happens to enzymes when the temperature rises above the optimum?

  Enzymes begin to denature and lose their complementary shape
• What is the consequence of enzyme denaturation on substrate binding?

  The substrate can no longer bind to the active site due to the change in shape
• What is the optimum temperature for enzyme activity?

  • The temperature at which the reaction rate is fastest
  • Varies for different enzymes
• What is the independent variable in the investigation of temperature effects on the rate of reaction?

  Temperature
• What is the dependent variable in the investigation of temperature effects on the rate of reaction?

  Rate of reaction
• What are the control variables in the investigation?

  Optimum pH, volume of enzyme/substrate, concentration of enzyme/substrate, time
• What is the purpose of a control experiment?

  To repeat the experiment exactly the same and use no enzyme
• How does the control experiment prove that results are due to the enzyme?

  By showing that the same experiment without the enzyme yields different results
• What is the definition of pH?

  It is a measure of acidity or alkalinity of a solution
• What does a pH of 1 indicate about an acid?

  It is a strong acid with a higher concentration of H+ ions
• What does a pH of 6 indicate about an acid?

  It is a weak acid with a lower concentration of H+ ions
• What does a pH of 8 indicate about a solution?

  It is a weak acid with a lower concentration of OH- ions
• What happens to an enzyme's structure if pH changes?

  The enzyme's tertiary structure and active site shape can change
• What is the effect of a competitive inhibitor on an enzyme's activity?

  It binds to the active site, blocking the substrate from binding
• How does a non-competitive inhibitor affect an enzyme?

  It binds to a site away from the active site, changing the enzyme's shape
• What happens to the enzyme-substrate complexes when a non-competitive inhibitor is present?

  They can no longer form due to the change in active site shape
• What is the relationship between enzyme concentration and rate of reaction?

  The rate of reaction is proportional to the concentration of enzyme
• What happens to the rate of reaction as substrate concentration increases?

  The rate of reaction increases until the active sites are fully occupied
• What is the formula for calculating percentage change?

  % Change = (Final - Start) / Start x 100
• What is the formula for calculating rate?

  Rate = change in Y / change in X
• What happens to the rate of reaction as temperature increases from 0-40°C?

  The rate of reaction increases
• What occurs to the rate of reaction when temperature exceeds 40°C?

  The rate of reaction rapidly decreases