C1.1 Enzymes and Metabolism

• What is a catalyst?


  A substance that increases the rate of a chemical reaction without being consumed or permanently altered.
• What role do enzymes play in life processes?


  Enzymes act as biological catalysts by speeding up biochemical reactions essential for life.
• Can enzymes be reused after speeding up chemical reactions?


  Yes, enzymes can be reused multiple times without being altered.
• What is metabolism?


  The total of all biochemical reactions taking place within an organism.
• What does enzyme specificity refer to?


  Enzyme specificity refers to the precise interaction between an enzyme and its substrate due to the enzyme's unique active site structure.
• How do enzymes regulate metabolism?


  Enzymes regulate metabolism by controlling the rate of metabolic reactions.
• What are anabolic reactions?


  Anabolic reactions build complex molecules from simpler ones.
• What are catabolic reactions?


  Catabolic reactions break down complex molecules into simpler ones.
• What are examples of anabolic processes?


  • Protein synthesis
  • DNA replication
  • Photosynthesis
• What are examples of catabolic processes?


  • Cellular respiration
  • Digestion of food
  • Breakdown of glycogen
• What are the properties of globular proteins?


  Globular proteins are soluble in water, spherical in shape, and perform dynamic functions like catalysis.
• How does the unique 3D structure of an enzyme affect its function?

  The unique 3D structure determines the specificity of its active site, which fits only specific substrates.
• What are the stages of enzyme catalysis?


  Substrate binds to the enzyme’s active site, enzyme-substrate complex forms, reaction occurs, product is released, enzyme is free to catalyze another reaction.
• What is the induced-fit model of enzyme action?


  The induced-fit model states that the enzyme's active site undergoes a slight shape change to accommodate the substrate more snugly, improving catalysis.
• How does molecular motion affect enzyme catalysis?

  Increased molecular motion (higher temperatures) increases the chances of random collisions between enzymes and substrates.
• How do the movements of enzymes and substrates compare in the cytoplasm?


  Both enzymes and substrates are mobile in the cytoplasm, while large substrates or immobilized enzymes may exhibit more restricted movement.
• What is denaturation in the context of enzymes?


  Denaturation is the loss of an enzyme's 3D structure due to factors such as temperature or pH changes, leading to loss of function.
• What causes denaturation of enzymes?

  High temperatures or extreme pH can disrupt the enzyme's structure, rendering it nonfunctional.
• What factors affect enzyme activity?


  Temperature, pH, and substrate concentration affect enzyme activity.
• What happens to reaction rates as temperature increases?


  Reaction rates increase until the enzyme denatures.
• What is the optimal pH range for enzymes?


  Each enzyme has an optimal pH range for its activity.
• What occurs at higher substrate concentrations?


  Higher substrate concentration increases reaction rate until saturation occurs.
• What should you be able to interpret regarding enzyme activity graphs?


  You should be able to interpret graphs showing enzyme activity changes with varying temperatures, pH levels, and substrate concentrations.
• What are the independent variables in enzyme experiments?


  Independent variables can include substrate concentration, temperature, or pH.
• What is the dependent variable in enzyme experiments?


  The dependent variable is the rate of reaction.
• What are controlled variables in enzyme experiments?

  Controlled variables include temperature, pH, and enzyme concentration.
• How is the enzyme reaction rate often measured?


  It is often measured in product formed per time (e.g., μmol/min).
• What are methods for measuring reaction rates in enzyme-catalyzed reactions?


  • Measure the amount of product formed
  • Measure the decrease in substrate concentration
• What are some investigative techniques used in enzyme experiments?

  • Spectrophotometry
  • Gas collection
  • Titration
• What is activation energy?


  Activation energy is the minimum amount of energy required to start a chemical reaction.
• How do enzymes affect activation energy?


  Enzymes lower the activation energy, making it easier for the reaction to occur.
• What should you be able to interpret regarding graphs of enzyme-catalyzed reactions?

  You should be able to interpret graphs showing the effect of enzyme-catalyzed reactions lowering activation energy compared to uncatalyzed reactions.