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Chapter 5: 10-16 The Working Cell - Enzymes

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Biology Homework Chapter 5: Enzyme Functions


Reading Preparation

Textbook assignment: Chapter 5: The Working Cell, sections 10-16. Read through the end-of-chapter summary and do a mental self-test using the multiple choice questions.

Study Notes

Web Lecture

Read the following weblecture before chat: Energy and Enzymes

Take notes on any questions you have, and be prepared to discuss the lecture in chat.

Study Activity

Perform the study activity below:

  • Let's put together some ideas. We know that acids can raise or lower the pH of a solution by adding H+ ions. We also know that many proteins (which often act as eznymes) use H-bonds to maintain their shape and perform their function. Use the interactive Lactase Enzyme Activity with Data Analysis to explore what happens if you vary the concentration of the enzyme, the temperature of the solution, and the pH of the solution. What are the optimal concentration, temperature, and pH for the enzyme activity? What happens if the concentration is too high or too low? What happens if the temperature is too high or too low? What happens if the pH is too high or too low?
    • Read the information on the home page about enzymes and possible questions to explore.
    • Read the background page.
    • Explore the model of enzyme function. What do you expect to happen as you change the temperature? As you change the acidity (pH)?
    • Run the simulation with different values:
      1. Accept the default values (500 mg/dL, 25 °C, pH = 7.0). Not the shape of the curve for glucose production. When does it level off?
      2. Change the concentration of the lactose to 250 mg/dL. How does the curve change?
      3. Change the concentration to 750 mg/dL. How does the curve change?
      4. Reset concentration to 500 mg/dL and do two more runs, varying the temperature from 15 to 70 °C. What happens to enzyme action? Why?
      5. Reset the temperature to 25 °C and vary the pH from 2 to 12. What happens to the enzyme action? Why?
      6. What happens if the lactose concentration is between 20-40 mg/dL, temperature is 37 °C, and pH is 7.4?
      7. Can you find an optimal set of conditions for enzyme action?

Chat Preparation Activities

Chapter Quiz

Lab Work

Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.