Jeffrey T. Kushner Chem 504 Lesson Plan Metabolism Objective Students will be able to provide an overview of the chemical reactions involved in Metabolism. Students will be able to identify the reactants and products of the different cycles and stages of Metabolism. Students will be able to describe chemical mechanisms and changes of the reactants to the products of the different cycles and stages of Metabolism. Students will be able to evaluate the ATP expenditure vs. the ATP acquired through Metabolism. Overview (Setting) This lesson is designed for a college prep chemistry class with an extended lab period. (This lab period may coincide with the lecture period or it may follow at some other time.) Students are connecting knowledge learned in last years Biology course and now beginning to develop a more comprehensive and complete understanding of the chemical nature of metabolism. By the end of this lesson, students will recognize that Metabolism is a complex chemical processes consisting of multiple entry pathways and potential ending structures with different ATP outcomes. This lesson will continue over two to three days to complete individual research and group discussion. At the end of the student investigation, the stages of metabolism will be reviewed to ensure accuracy. Required Materials Laptop cart with 25-30 computers Internet access Pre-Class Activity One question, five minute free-write: Describe the word Metabolism. What does it mean? Why is it important to you? What does it do for you? Is it a long or short process? Can it be controlled? What affects metabolism? Does metabolism occur anywhere else other than your body?
Content Metabolism Overview Notes (Introduction) 1) Metabolism a) Totality of an organism s chemical processes b) Catabolic pathways i) Release energy by breaking down complex molecules to simpler compounds (1) Glucose broken down to CO 2 and H 2 O (2) Energy stored in molecules becomes available to do work for cell c) Anabolic pathways i) Consume energy to build complex molecules from simple compounds ii) Synthesis of a protein d) Interactions between catabolism and anabolism i) Energy coupling e) Bioenergetics i) Study of how organims manage their energy resources f) Overview Main Steps i) Glycolysis (1) Glucose Conversion (2) Pyruvate Decarboxylation (3) Gluconeogenesis ii) Citric Acid Cycle iii) Electron Transport Chain iv) Anaerobic Respiration (1) Lactic Acid Fermentation (2) Ethanol Fermentation
METABOLISM EXTRA (NOT GIVEN TO STUDENTS, BUT INTSTRUCTORS GUIDE) a) Overview Main Steps i) Glycolysis (1) Splitting of sugar (2) Six-carbon sugar is split into two-three carbon sugars (a) 10 steps (i) phase one energy investment 1. cell spends ATP to phosphorylate molecules (ii) phase two energy yielding 1. ATP is produced through substrate-level phosphorylation 2. NAD+ is reduced to NADH 3. 2ATP +2NADH produced ii) Glucose Conversion (1) Other sugar molecules converted to glucose iii) Pyruvate Decarboxylation (1) Links pathways between Glycolysis and Citric Acid Cycle (a) Converson of Pyruvate to AcetylCoA iv) Gluconeogenesis (1) Formation of glucose from non-sugar carbon compounds v) Citric Acid Cycle (1) Acetyl CoA (a) 2 carbons enter cycle as acetyl fragment (b) 2 carbons exit as CO 2 (c) Majority of energy stored in acetyl group is transferred to NAD+ and FAD+ (2) 1ATP produced per turn of citric acid cycle vi) Electron Transport Chain (1) Electrons removed from glucose during glycolysis and citric acid cycle (a) Transferred by NADH and FADH (b) Repeating oscillation of molecules between reduced and oxidized state (2) No ATP gained directly (3) Main function is to ease electrons from glucose (food) to oxygen vii) Anaerobic Respiration (1) Metabolic pathways for when oxygen is not present viii) Lactic Acid Fermentation (1) Conversion of pyruvate directly to NADH (2) No CO 2 is released (3) Lacate forms as waste ix) Ethanol Fermentation (1) Conversion of pyruvate to ethyl alcohol (2) Occurs in two steps (a) Pyruvate is converted to acetaldehyde (b) Acetaldehyde is reduced by NADH to alcohol
Structured Practice (Classwork) Jigsaw Activity Students will be broken into heterogeneous groups containing three to five students. Each student group will be given a specific phase, region, or cycle of metabolism. They will be guided to selected research sites and allowed to find references on their own to aid them in completing the activity. Students will be asked to find the following: Once research is completed, students will separate into a new set of groups to discuss the learned information. Each teaching group will contain at least one member from each research team. Groups will collaborate, share information, and look to determine how and where the various reactants and products are involved in metabolism. Resource (Reference Sites suggested) Rensselaer Polytechnic Institute http://www.rpi.edu/dept/bcbp/molbiochem/mbweb/mb1/mb1index.html University of Arizona http://www.biology.arizona.edu/biochemistry/problem_sets/metabolism/metabolism.html Indiana University http://web.indstate.edu/thcme/mwking/glycolysis.html Harris College http://science.nhmccd.edu/biol/glylysis/glylysis.html Smith College http://www.science.smith.edu/departments/biology/bio231/glycolysis.html http://www.science.smith.edu/departments/biology/bio231/krebs.html http://www.science.smith.edu/departments/biology/bio231/etc.html John Kyrk Science http://www.johnkyrk.com/glycolysis.html http://www.johnkyrk.com/krebs.html Estrella Mountain Community College http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookglyc.html
Independent Practice (Homework) Since students completed the free write activity at the beginning of class, they wil be asked to write a post activity reflection. On the same piece of paper, they will be asked to write a two paragraph (minimum) on metabolism. Paragraph 1 Describe Metabolism. What does it mean? What occurs during metabolism? Is it a long process or short process? Why is it important to you? Can it be controlled? What affects metabolism? Does metabolism occur anywhere else other than your body? Paragraph 2 Summarize metabolism. What are the main stages of metabolism? How is ATP produced? Why is ATP consumed if it supposed to be produced? How does metabolism continue if an ample supply of oxygen is not available?
Group 1 Glycolysis
Group 2 Citric Acid Cycle
Group 3 Glucose Conversion & Pyruvate Decarboxylation
Group 4 Gluconeogenesis
Group 5 Lactic Acid Fermentation
Group 6 Ethanol Fermentation
Group 7 Electron Transport Chain
REFERENCES Metabolism. Chemistry; A Project of the American Chemical Society. Freeman. New York, 2005. Garrett, R. H., and Grisham, C.M. Principles of Biochemistry with a Human Focus, updated Third Edition. Brooks/Cole. Belmont, CA, 2007. McMurry, John., and Casellion, Mary, E. Metabolism Fundamentals of General, Organic, and Biological Chemistry; Fourth Edition. Pearson Education, Inc. New Jersey. 2003. Cambell, Neil. Metabolism. Biology, Third Edition. The Benjamin/Cummings Publishing Company, Inc. 1993.