Biology 5th Edition ©1999
by Campbell, Reece, Mitchell
Week 3: Macromolecules and Metabolism with a Focus on Enzymes
Chapter 5: The Structure and Function of Macromolecules
Chapter 6: An Introduction to Metabolism
College Board Performance Objectives:
- Describe the role of carbon in the molecular diversity of life.
- Explain how cells synthesize and break down macromolecules.
- Explain how structures of biologically important molecules (carbohydrates, lipids, proteins, nucleic acids) account for their functions.
- Explain how the laws of thermodynamics relate to the biochemical processes that provide energy to living systems.
- Explain how enzymes regulate the rate of chemical reactions.
- Describe the role of catabolic and anabolic pathways in the energy exchanges of cellular metabolism.
- Describe how the specificity of an enzyme depends on its structure.
- Describe how the activity of an enzyme is regulated.
College Board Lab Objectives:
- Understand the relationship between the structure and function of enzymes.
- Understand the concepts of initial reaction rates of enzymes.
- Understand how the concept of free energy relates to enzyme activity.
- Design labs that test changes in temperature, pH, enzyme concentration, and substrate concentration can affect the initial reaction rates of enzyme-catalyzed reactions.
- Explain how environmental factors affect the rate of enzyme-catalyzed reactions.
Suggested Laboratory Experiments:
Biology AP* Laboratory 2, Enzyme Catalysis (Adapted to using Gas Pressure Sensors with Calculator-Based Laboratories or Computer-Based Laboratories.) The traditional catalase lab uses potassium permangenate, and takes much time. The use of the biology gas pressure senor with the computer or CBL allows for an efficient lab that is easy to understand. The Vernier Web site has information about using sensors.
- Chapter 5: The Structure and Function of Macromolecules, pp.58–82
- Chapter 6: An Introduction to Metabolism, pp. 83–101
- Instructor's Guide, pp. 39–65
- Student Study Guide, pp. 22–38
- Test Bank, pp. 50–64
- Lab Manual: Lab Topic 2: Enzymes, pp. 33–56
- CD-ROM: Chapters 5 and 6 include narrated presentations, activities, and links to the Internet.
- Chapter 5: The Structure and Function of Macromolecules—2 days
- Chapter 6: An Introduction to Metabolism—3 days
- To emphasize the various properties of enzymes, have the student link together to form the primary structure of the enzyme. Have them form secondary, tertiary, and quaternary structure. Make them have an active site that is the shape of a triangle. The teacher can be the substrate and can fit into the active site. Then pretend that heat is applied and that the enzyme begins to denature. The question is: will the substrate fit and why? This activity could also be done with a long chain of beads on a smaller scale.
- In an envelope, make an ATP study kit. Place adenine (a triangular piece of paper), ribose (a five-sided piece of paper), and three phosphates (small circular pieces of paper). Have the students assemble the ATP model upon a piece of paper. Once the molecules are in place, have students draw straight lines to represent normal covalent bonds that are between the adenine and ribose and the ribose and the first phosphate. Then use ~lines to represent the high-energy phosphate bonds that are between the other two phosphates. If time permits, have students draw the structures of each of the molecules on the shaped pieces of paper.
- Block Scheduling
Chapter 5 can be accomplished in little more than one block and Chapter 6 can be covered in about two blocks.
- condensation reaction, p. 58
- hydrolysis, p. 59
- carbohydrate, p. 60
- monosaccharide, p. 60
- disaccharide, p. 61
- polysaccharide, p. 62
- starch, p. 62
- glycogen, p. 63
- cellulose, p. 63
- Chitin, p. 64
- lipid, p.65
- phospholipid, p. 67
- steroids, p. 68
- protein, p. 68
- amino acid, p. 68
- polypeptides, p. 68
- peptide bond, p. 70
- protein structure, p. 71
- denaturation, p. 75
- nucleic acids, p. 76
- nucleotides, p. 77
- catabolic pathway, p. 83
- anabolic pathway, p. 83
- energy, p. 84
- entropy, p. 85
- free energy, p. 85
- energy coupling, p. 88
- exergonic reaction, p. 88
- endergonic reaction, p. 88
- adenosine triphosphate, p. 89
- enzyme, p. 91
- catalyst, p. 91
- activation energy, p. 91
- substrate, p. 92
- Competitive inhibitors, p. 94
- noncompetitive inhibitors, p. 95
- allosteric regulation, p. 95
- feedback inhibition, p. 96
- cooperativity, p. 96
Critical thinking questions and end-of-chapter activities are included in these exercises.
- Challenge Questions, p. 82 #1 and p. 98 #1
- Science, Technology, and Society, p. 52 #1 and p. 98 #1
- Also, have students bring to class a food that is predominately carbohydrate, protein, and fat. A discussion on the selected items will show that most foods are a combination of the macromolecules.
Troubleshooting Tips/Error Traps:
- The structure and function of macromolecules is important in every level of biology; students must have a full understanding. Also, the structure and function of enzymes is foundational to the study of most biological principles. The investment of class interaction on these topics is critical to successfully acquiring many other concepts.
- The use of gas pressure sensors with calculators or computers helps to make the catalase lab an enjoyable inquiry lab. The gas pressure sensors allow the students to relate the amount of pressure (oxygen bubbles) to the rate of the reaction. The students see that they can follow the rate of the reaction by determining the amount of oxygen produced. They are also able to get the slopes of the lines quickly. The traditional lab that utilizes potassium permanganate is a slow and cumbersome lab that has many steps. Be sure that students understand the assay method and that all safety precautions are taken. Students need help understanding that they are determining the amount of hydrogen peroxide not reacted and that they have to substrate the amount of unused hydrogen peroxide from the total amount of hydrogen peroxide to get the amount of hydrogen peroxide that is used. They need to understand that they need to follow the amount of hydrogen peroxide used in the reaction.