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• What are metabolic pathways?


  Integrated and controlled pathways of enzyme-catalyzed reactions within a cell
• What types of steps can metabolic pathways have?


  Reversible steps, irreversible steps, and alternative routes
• What are the two types of reactions within metabolic pathways?

  Anabolic and catabolic reactions
• What do anabolic reactions do?


  Build up large molecules from small molecules and require energy
• What do catabolic reactions do?


  Break down large molecules into smaller molecules and release energy
• How are metabolic pathways controlled?


  By the presence or absence of particular enzymes and the regulation of key enzymes' reaction rates
• When is an enzyme produced?


  Only when required, saving ATP and resources
• What is the affinity of substrate molecules for the active site?


  Substrate molecules have a high affinity for the active site
• How does the shape of the active site affect substrate molecules?


  The shape of the active site determines the orientation of the substrate molecules
• What happens to the products after the reaction in the active site?


  Products have a low affinity allowing them to leave the active site
• What is induced fit in enzyme activity?


  Induced fit occurs when the active site changes shape to better fit the substrate after binding
• How does induced fit affect activation energy?


  It helps lower the activation energy required for the reaction to take place
• What effect does temperature have on enzyme activity?


  An increase in temperature causes an increase in enzyme activity up to an optimum temperature
• What is the optimum temperature for enzymes?


  It is when the enzyme works at its best, with the highest activity and lowest reaction time
• What happens to enzymes when they become denatured?


  The active site changes shape, preventing the substrate from fitting
• How does pH affect enzyme reactions?


  Enzymes work within a range of pH values but have an optimum pH value
• What is the effect of increasing substrate concentration on enzyme activity?


  Increasing substrate concentration increases enzyme activity until a maximum is reached
• Why does product production not remain constant in enzyme reactions?


  Because substrate is used up, limiting the rate of reaction
• How does substrate and product concentration affect the rate of reaction?


  A high concentration of substrate and a low concentration of product will increase the rate of reaction
• What role do inhibitors play in enzyme activity?


  Inhibitors reduce enzyme activity
• What are competitive inhibitors?


  Competitive inhibitors bind at the active site, preventing substrate binding
• How can the effect of competitive inhibitors be reversed?


  By increasing substrate concentration
• What are non-competitive inhibitors?


  Non-competitive inhibitors bind away from the active site and change its shape
• How does increasing substrate concentration affect non-competitive inhibitors?


  It has no effect on reaction rate because the active site cannot bind substrate
• What is feedback inhibition?


  It occurs when the end product in a metabolic pathway inhibits an earlier enzyme
• How does feedback inhibition prevent wasteful buildup of end products?


  The final end product binds to a second site on the first enzyme, changing its shape
• What happens as the concentration of the end product increases in feedback inhibition?


  First enzyme inhibition increases, leading to a reduction in substrate molecules
• What is the cycle of feedback inhibition?


  As end product concentration increases, inhibition increases, reducing end product, which decreases inhibition
• What are the factors affecting the rate of enzyme reactions?


  • Temperature
  • pH
  • Substrate concentration
  • Presence of inhibitors
• What are the effects of temperature on enzyme activity?


  • Increase in temperature raises enzyme activity to an optimum
  • Enzyme activity is highest at optimum temperature
  • Enzymes can become denatured at high temperatures
• What are the effects of pH on enzyme activity?


  • Enzymes work within a range of pH values
  • Each enzyme has an optimum pH value
• What are the effects of substrate concentration on enzyme activity?


  • Increasing substrate concentration increases enzyme activity until a maximum
  • High substrate concentration can increase reaction rate
  • Low substrate concentration can decrease reaction rate
• What are the effects of inhibitors on enzyme activity?


  • Competitive inhibitors bind at the active site
  • Non-competitive inhibitors bind away from the active site
  • Feedback inhibition prevents wasteful buildup of end products
• What is the cycle of feedback inhibition?


  • As end product concentration increases, first enzyme inhibition increases
  • This leads to a reduction in substrate molecules
  • Reduction in end product leads to decreased inhibition