Textbook Question
What are the products of digestion of proteins, triacylglycerols, maltose, sucrose, lactose, and starch?
Ch.22 Carbohydrate Metabolism
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Not the one you use?Change textbook
Chapter 22, Problem 30b
The pathway that converts glucose to acetyl-CoA is often referred to as an “aerobic oxidation pathway.”
(b) Thinking back to Chapter 20, where does molecular oxygen enter the picture?
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Recall that the pathway converting glucose to acetyl-CoA involves glycolysis followed by the pyruvate dehydrogenase complex. Glycolysis occurs in the cytoplasm and does not directly involve oxygen, making it an anaerobic process.
Understand that molecular oxygen (O₂) is not directly involved in the conversion of glucose to acetyl-CoA. Instead, oxygen plays a critical role in the electron transport chain (ETC), which is part of aerobic respiration.
In Chapter 20, molecular oxygen enters the picture during the electron transport chain, which occurs in the mitochondria. Oxygen acts as the final electron acceptor in the chain, combining with electrons and protons to form water (H₂O).
Recognize that the electron transport chain is indirectly linked to the earlier steps of glucose metabolism. The NADH and FADH₂ produced during glycolysis, the pyruvate dehydrogenase complex, and the citric acid cycle donate electrons to the ETC, where oxygen is required.
Conclude that while molecular oxygen is not directly involved in the conversion of glucose to acetyl-CoA, it is essential for the continuation of aerobic respiration, as it allows the regeneration of NAD⁺ and FAD, which are necessary for glycolysis and the citric acid cycle to proceed.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Aerobic Oxidation
Aerobic oxidation is a metabolic process that requires oxygen to convert glucose into energy. This pathway involves glycolysis, the citric acid cycle, and oxidative phosphorylation, ultimately leading to the production of ATP. Oxygen serves as the final electron acceptor in the electron transport chain, allowing for efficient energy production.
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Aerobic Respiration Summary Concept 1
Acetyl-CoA
Acetyl-CoA is a crucial metabolic intermediate that plays a key role in energy production and biosynthesis. It is formed from the breakdown of carbohydrates, fats, and proteins and enters the citric acid cycle, where it is further oxidized to generate ATP. Understanding its formation from glucose is essential for grasping the aerobic oxidation pathway.
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Role of Molecular Oxygen
Molecular oxygen is vital in aerobic respiration as it facilitates the complete oxidation of glucose. It enters the metabolic pathway during the electron transport chain, where it accepts electrons and combines with protons to form water. This process not only drives ATP synthesis but also prevents the accumulation of electrons, maintaining the flow of the metabolic pathway.
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Related Practice
Textbook Question
Fatty acids from stored triacylglycerols (fat) are not available for gluconeogenesis. Speculate why we do not have the enzymes to directly convert fatty acids into glucose. Plants (especially seeds) do have enzymes to convert fatty acids into carbohydrates. Why are they so lucky?
Textbook Question
What are the major monosaccharide products produced by digestion of carbohydrates?
Textbook Question
Name the molecules used for gluconeogenesis. What are the sources of these molecules? Under what conditions would gluconeogenesis occur?
Textbook Question
Outline the conditions that direct pyruvate toward the following:
d. Glucose synthesis (gluconeogenesis)
In what tissues or organisms is each pathway present?
Textbook Question
What three products are formed from pyruvate under aerobic, anaerobic, and fermentation conditions?