Competency 208.5.4: Enzymology and Catalytic Mechanism - The graduate constructs models of enzymes, demonstrates how enzymes act as a catalyst in a reaction and factors that influence this reaction, and solves enzyme and catalysis problems.
Competency 208.5.5: Carbohydrate Metabolism, Adenosine Triphosphate (ATP) - The graduate constructs models of carbohydrates and demonstrates metabolism of carbohydrates; demonstrates how adenosine triphosphate (ATP) is essential to energy transfer in the cell and how irregularities in ATP synthesis in the cell can cause cytopathologies.
More and more researchers are discovering that many diseases are caused by biochemical deficiencies or defects. That is, instead of indicating that a disease is caused by a nutritional deficiency, researchers recognize that an underlying cause may be a single molecular structure within a cell that fails to turn a cellular process on or off. This is particularly true regarding metabolism. For this task, you will consider the biochemical implications in a metabolic disorder involving a normal component of food—fructose.
Assemble your work in a document (e.g., Microsoft Word, Google Document) (suggested length of 3–4 pages, including diagrams, text explanations, and references).
Note: Please save submission documents as *.doc, *.docx, *rtf, or *.pdf files. If you are using Google Documents, you must save the file in *.pdf format and upload the *.pdf file.
A. Demonstrate your understanding of the biochemical basis of hereditary fructose intolerance (HFI) by doing the following:
1. Describe two important features that make all enzymes catalysts.
2. Explain how enzymes act as protein catalysts in the first two steps of fructose metabolism in the liver.
3. Provide an original, clearly labeled diagram, or series of diagrams, that illustrates the following:
• the lock and key model OR the induced fit model of enzymatic activity
Note: The diagram must show the entire enzymatic cycle, including product formation and release.
• the activation energy of a reaction in the presence and absence of an enzyme
4. Discuss the specific substrate acted on by aldolase B during the metabolism of fructose, including how the substrate is made.
5. Explain the role of aldolase B in the metabolism of fructose, including the products of the reaction.
a. Identify the different pathways the products of aldolase B can enter.
6. Discuss how a deficiency in aldolase B is responsible for HFI by doing the following:
a. Explain how the amount of the substrate of aldolase B is impacted by the deficiency.
b. Explain the role of the substrate in producing the symptoms of HFI.
B. Explore how mitochondrial disease can occur at multiple levels in different mitochondrial processes by doing the following:
1. Explain what would hypothetically happen to the amount of ATP available to a cell if the entire Cori cycle (glucose going to lactate and then back to glucose) were to occur and remain within that single cell (i.e., a muscle cell).
a. Justify your response to part B1 by providing specific numbers of ATP generated or used in the different parts of the cycle.
2. Create an original dynamic diagram that shows how the citric acid cycle (CAC) is central to aerobic metabolism.
a. Illustrate the following elements in your diagram:
• how different metabolites enter the cycle
• the entire CAC, including the names of all intermediates, enzymes, and products
• where the products of the CAC go in order to make ATP
• the role of oxygen in this process
Note: A dynamic diagram is a clearly labeled diagram that uses arrows to indicate movement and interactions.
3. Explain where in the CAC a hypothetical defect of an enzyme could occur that would decrease the overall ATP production of the mitochondria.
Note: This is a hypothetical defect, so the explanation should not include descriptions of any known disease.
a. Discuss what happens to the product of the enzyme from part B3, that includes each of the following points:
• whether the entire cycle will continue to function
• what will happen to the cycle products and their contribution to ATP production
4. Explain the specific role of coenzyme Q10 in the electron transport chain.
a. Explain how coenzyme Q10 leads to ATP synthesis.
i. Describe the electron transport chain and oxidative phosphorylation.
C. When you use sources, include all in-text citations and references in APA format.
Note: When using sources to support ideas and elements in an assessment, the submission MUST include APA formatted in-text citations with a corresponding reference list for any direct quotes or paraphrasing. It is not necessary to list sources that were consulted if they have not been quoted or paraphrased in the text of the assessment.
Note: No more than a combined total of 30% of a submission can be directly quoted or closely paraphrased from sources, even if cited correctly. For tips on using APA style, please refer to the APA Handout web link included in the General Instructions section.