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CHEM204: Bioorganic Chemistry

Unit 4: Carbohydrate Metabolism   Carbohydrates have the general formula CnH2nOn.  Autotrophs synthesize carbohydrates (e.g. plants synthesize simple sugar from carbon dioxide and water through photosynthesis).  The central simple carbohydrate is glucose, because it is delivered as an energy source to all cell types in most multicellular organisms.  Carbohydrates may be stored in polysaccharide form (e.g. glycogen and starch, converted to energy or used as building blocks in a variety of biosynthetic pathways).  Other polysaccharides (e.g. chitin and cellulose) are structural and used for cellular support.  This unit explains the major catabolic and anabolic pathways of carbohydrate metabolism.

Unit 4 Time Advisory
This unit should take you approximately 25.5 hours to complete.

☐    Subunit 4.1: 5 hours

☐    Subunit 4.2: 2 hours

☐    Subunit 4.3: 2.5 hours

☐    Subunit 4.4: 4 hours

☐    Subunit 4.5: 2 hours

☐    Subunit 4.6: 2 hours

☐    Subunit 4.7: 3 hours

☐    Subunit 4.8: 2 hours

☐    Subunit 4.9: 3 hours

Unit4 Learning Outcomes
Upon successful completion of this unit, the student will be able to:
- Identify the biological pathway which leads to the synthesis of ATP in all living cells investigated so far. - Determine the significance of fermentation during anaerobic metabolism. - Describe the effect of allosteric regulators on the activity of phosphofructokinase in glycolysis. - Explain why certain metabolic pathways are called “cycles.” - Explain what happens in a eukaryotic cell that lacks oxalic acid or ribulose bisphosphate. - Compare and contrast the Citric Acid Cycle and the Calvin Cycle.

4.1 Digestion and Hydrolysis of Complex Carbohydrates   - Reading: University of Kansas Medical Center: Scott Goodman’s “Interconversion of Sugars” Link: University of Kansas Medical Center: Scott Goodman’s "Interconversion of Sugars” (HTML)
 
Instruction: Please click on the link above, and study this section on “Interconversion of Sugars.”  Note that only glucose and the metabolic intermediates of glycolysis are used to produce energy.
 
Studying this resource will take approximately 1 hour to complete.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Reading: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Glycogen Metabolism” Link: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Glycogen Metabolism” (HTML)
     
    Instruction: Please click on the link above, and study this entire webpage.  Please note that animal cells store glucose in glycogen.  Glycogen is a glucose polymer.  Glycogen synthesis and glycogen breakdown are reciprocally regulated as blood sugar levels change.
     
    Studying this resource will take approximately 2 hours to complete.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Reading: University of California, Davis: ChemWiki: “Cellulose,” “Glycogen,” and “Starch” Link: University of California, Davis ChemWiki: “Cellulose” (PDF), “Glycogen” (PDF) and “Starch” (PDF)

    Instructions: Read each article to understand the structure, function, and digestive processes of the three polysaccharides: cellulose, glycogen, and starch.  This article also explains how each of these substances are synthesized by plants and animals to be stored as food and ultimately used as energy.

    Terms of Use: This resource is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. It is attributed to the University of California, Davis, and the original versions can be found here.

4.2 Glucose Catabolism: Glycolysis   - Reading: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Glycolysis and Fermentation” Link: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Glycolysis and Fermentation” (HTML)
 
Instruction: Please click on the link above, and read the entire webpage for information on the glycolysis pathway, fermentation, and regulation of glycolysis.  Please note that this resource also covers the topic outlined in Subunit 4.3.1. 
 
Studying this resource will take approximately 2 hours to complete.
 
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4.3 Transformations of Pyruvate   4.3.1 Conversion of Pyruvate to Lactate or Ethanol   - Reading: Rensselaer Polytechnic Institute: Joyce J. Diwan's "Glycolysis and Fermentation" Link: Rensselaer Polytechnic Institute: Joyce J. Diwan's "Glycolysis and Fermentation" (HTML)
 
Instruction: Please click on the link above, select "Fermentation" under "Contents of this page,” and study the description of the two pathways in this section.
 
This resource will take approximately 1 hour to complete.
 
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4.3.2 Conversion of Pyruvate to Acetyl CoA   - Reading: Rensselaer Polytechnic Institute: Joyce J. Diwan's "Pyruvate Dehydrogenase & Krebs Cycle" Link: Rensselaer Polytechnic Institute: Joyce J. Diwan's "Pyruvate Dehydrogenase & Krebs Cycle" (HTML)
 
Instruction: Please click on the link above, and study "Pathway Localization,” "Pyruvate Dehydrogenase,” “Roles of Acetyl-Coenzyme A,” and "Regulation of Pyruvate Dehydrogenase" sections on this page.
 
This resource will take approximately 1 hour and 30 minutes to complete.
 
Terms of Use: Please respect the copyright and terms of use on the webpage displayed above.

4.4 The Citric Acid Cycle   - Reading: Clackamas Community College: Sue Eggling’s “Citric Acid Cycle” Link: Clackamas Community College: Sue Eggling’s “Citric Acid Cycle” (HTML)
 
Instruction: Please click on the link above, and study the entire webpage.  Note that the Citric Acid Cycle is also called the Szent-Györgyi – Krebs Cycle.  Make sure to take notes when you study this webpage.  Please note that oxaloacetic acid is necessary to start the cycle, and it is recycled by the end of the cycle.  Check your knowledge: write down the ten consecutive reactions of the Citric Acid Cycle pathway without looking at the webpage.
 
Studying this resource will take approximately 4hours to complete.
 
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4.5 Glucose Biosynthesis: Gluconeogenesis   - Reading: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Gluconeogenesis” Link: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Gluconeogenesis” (HTML)
 
Instruction: Please click on the link above, and study the entire page to learn about gluconeogenesis.  
 
Studying this resource will take approximately 2 hours to complete.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.6 The Pentose Phosphate Pathway   - Reading: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Pentose Phosphate Pathway” Link: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Pentose Phosphate Pathway” (HTML)
 
Instruction: Please click on the link above, and study this webpage to learn about the pentose phosphate pathway.  
 
Studying this resource will take approximately 2 hours to complete.
 
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4.7 Oxidative Phosphorylation   - Reading: The Medical Biochemistry Page: Michael W. King’s “Biological Oxidations” Link: The Medical Biochemistry Page: Michael W. King’s “Biological Oxidations” (HTML)

 Instruction: Please click on the link above, and study the text in
its entirety to learn about biological oxidations.    
    
 Studying this resource will take approximately 3 hours to
complete.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

4.8 Photosynthesis: The Reductive Pentose Phosphate (Calvin) Cycle   - Reading: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Calvin Cycle – Photosynthetic Carbon Reactions” Link: Rensselaer Polytechnic Institute: Joyce J. Diwan’s “Calvin Cycle – Photosynthetic Carbon Reactions” (HTML)
 
Instruction: Please click on the link above, and study this entire webpage to learn about the Calvin Cycle.  
 
Studying this resource will take approximately 2 hours to complete.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Reading: The Medical Biochemistry Page: Michael W. King’s “Metabolic Disorders Associated with the PPP” Link: The Medical Biochemistry Page: Michael W. King’s “Metabolic Disorders Associated with the PPP” (HTML)
     
    Instruction: Please click on the link above, and study the “Metabolic Disorders Associated with the PPP” section, as well as the “Chronic Granulomatous Disease” and “Erythrocytes and the Pentose Phosphate Pathway” sections that follow.  
     
    Studying this resource will take approximately 1 hour 30 minutes to complete.
     
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4.9 Clinical Significance of Carbohydrate Metabolism   - Reading: The Medical Biochemistry Page: Michael W. King’s “Glycogen Storage Diseases” Link: The Medical Biochemistry Page: Michael W. King’s “Glycogen Storage Diseases” (HTML)
 
Instruction: Please click on the link above, and study the "Glycogen Storage Disease" section including the "Mechanism of glucose-6-phosphate conversion to free glucose," the "Interrelationships of metabolic pathway disruption in von Gierke disease" figures, and the “Table of Glycogen Storage Diseases” on this webpage.  
 
Studying this resource will take approximately 1 hour and 30 minutes to complete.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.