Enzymes

• What are enzymes?

  Biological catalysts essential for metabolism
• What is the active site of an enzyme?

  It is where substrates bind and undergo catalysis
• What is the shape of the active site formed by?

  A few amino acids
• Why is the shape and charge distribution of the active site important?

  They are crucial for substrate specificity
• What are the differences between the Lock and Key Model and the Induced Fit Model?

  • Lock and Key Model: Suggests a perfect fit between enzyme and substrate.
  • Induced Fit Model: Proposes that the active site changes shape upon substrate binding.
• How does hexokinase function in glucose metabolism?

  It changes shape to enclose glucose, similar to a venus flytrap
• What are the steps in the enzyme catalysis mechanism?

  1. Substrate Binding
  2. Formation of Enzyme-Substrate Complex
  3. Catalysis
  4. Product Release
  5. Enzyme Regeneration
• How do enzymes affect activation energy?

  They lower activation energy, allowing reactions to proceed faster
• What happens to enzyme activity as temperature increases?

  Activity increases until an optimal point, then decreases due to denaturation
• What is a common mistake students make regarding enzyme activity and temperature?

  They think enzyme activity increases indefinitely with temperature
• What is the effect of pH on enzyme activity?

  Each enzyme has an optimal pH, and extreme pH can denature enzymes
• How does substrate concentration affect reaction rate?

  Reaction rate increases with substrate concentration until it reaches maximum velocity (Vmax)
• What is the purpose of a double reciprocal (Lineweaver-Burk) plot in enzyme kinetics?

  To determine Vmax and the Michaelis-Menten constant
• What causes enzyme denaturation?

  Extreme temperatures, extreme pH, certain chemicals, and physical factors
• What is an example of denaturation in everyday life?

  Cooking an egg changes proteins from liquid to solid
• What are the advantages of immobilized enzymes in industry?

  • Reusability
  • Stability
  • Continuous Operation
  • Product Purity
• What are the methods of enzyme immobilization?

  1. Adsorption
  2. Covalent Bonding
  3. Entrapment
  4. Cross-linking
• How is glucose isomerase used in high-fructose corn syrup production?

  It is immobilized to convert glucose to fructose
• What enzyme is used to produce lactose-free milk?

  Lactase
• What is the process for producing lactose-free milk?

  1. Pasteurize milk
  2. Add lactase
  3. Incubate for breakdown
  4. Ultra-pasteurize to inactivate lactase
• What is the benefit of using immobilized lactase in milk production?

  It allows for continuous production and easier recovery
• What should be considered when testing enzyme activity?

  • Control Variables
  • Range of Values
  • Replication
  • Measurement of Activity
• What is a common mistake in experimental design for enzyme activity testing?

  Forgetting to use buffer solutions, which can alter pH
• What materials are needed for an experiment on the effect of pH on enzyme activity?

  • Enzyme solution (e.g., catalase)
  • Substrate solution (e.g., hydrogen peroxide)
  • Buffer solutions of various pH values
  • Stopwatch
  • Gas collection apparatus
• What is the procedure for measuring the effect of pH on enzyme activity?

  1. Prepare enzyme-buffer mixtures at different pH values
  2. Add substrate and start timing
  3. Measure gas produced over time
  4. Repeat for each pH and plot enzyme activity vs. pH
• How can substrate concentration effects be studied in enzyme activity?

  By preparing a range of concentrations and measuring initial reaction rates
• What is an example of investigating substrate concentration effects?

  Using amylase and starch to measure starch breakdown
• What does metabolism encompass?

  All enzyme-catalyzed reactions in a cell, providing energy and enabling synthesis of new materials
• What are the differences between anabolic and catabolic reactions?

  • Anabolic Reactions: Build complex molecules from simpler ones (e.g., photosynthesis).
  • Catabolic Reactions: Break down complex molecules into simpler ones (e.g., cellular respiration).
• What is the definition of activation energy (E_A)?

  Energy required for a reaction to proceed
• What is enzyme specificity?

  Enzymes have specific shapes that allow them to bind only to complementary substrates
• How do temperature and pH affect enzyme activity?

  • Low temperatures reduce kinetic energy, slowing reactions.
  • Optimal temperatures maximize activity, while high temperatures can cause denaturation.
  • pH changes affect enzyme charge and shape, impacting binding and function.
• How can enzyme activity be measured?

  • Measure time taken for reactions
  • Assess product formation or substrate consumption
• Why is understanding enzyme function important?

  It is crucial for appreciating their role in biological systems and industrial applications