Textbook Question
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?
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 28
Name the molecules used for gluconeogenesis. What are the sources of these molecules? Under what conditions would gluconeogenesis occur?
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Gluconeogenesis is the metabolic pathway that generates glucose from non-carbohydrate precursors. Begin by identifying the primary molecules used in gluconeogenesis: lactate, glycerol, and glucogenic amino acids (e.g., alanine).
Explain the sources of these molecules: lactate is produced during anaerobic glycolysis in muscle cells, glycerol is derived from the breakdown of triglycerides in adipose tissue, and glucogenic amino acids come from the breakdown of proteins during fasting or starvation.
Discuss the conditions under which gluconeogenesis occurs: it typically happens during periods of fasting, starvation, or intense exercise when blood glucose levels are low, and the body needs to maintain glucose homeostasis for energy, especially for the brain and red blood cells.
Highlight the role of hormones in regulating gluconeogenesis: glucagon and cortisol promote gluconeogenesis, while insulin inhibits it. This hormonal regulation ensures that glucose production aligns with the body's energy needs.
Conclude by emphasizing the importance of gluconeogenesis in maintaining blood glucose levels during prolonged fasting or low carbohydrate intake, ensuring a continuous energy supply for vital organs.
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Key Concepts
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Gluconeogenesis
Gluconeogenesis is the metabolic process through which glucose is synthesized from non-carbohydrate precursors. This pathway primarily occurs in the liver and, to a lesser extent, in the kidneys. It is crucial for maintaining blood glucose levels during fasting or intense exercise when carbohydrate stores are depleted.
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1:23
Gluconeogenesis Example 2
Precursors for Gluconeogenesis
The primary molecules used in gluconeogenesis include lactate, glycerol, and certain amino acids, particularly alanine. Lactate is produced during anaerobic glycolysis, glycerol is derived from triglycerides, and amino acids are released from protein breakdown. These precursors are converted into glucose through a series of enzymatic reactions.
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1:23Gluconeogenesis Example 2
Regulation and Conditions for Gluconeogenesis
Gluconeogenesis is regulated by hormonal signals, primarily glucagon and cortisol, which promote glucose production during fasting. It typically occurs under conditions of low carbohydrate availability, such as prolonged fasting, low-carbohydrate diets, or intense physical activity, ensuring that the body maintains adequate glucose levels for essential functions.
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1:23Gluconeogenesis Example 2
Related Practice
Textbook Question
Outline the conditions that direct pyruvate toward the following:
c. Conversion to lactate
In what tissues or organisms is each pathway present?
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
Outline the conditions that direct pyruvate toward the following:
b. Conversion to ethanol and CO2
In what tissues or organisms is each pathway present?
Textbook Question
Outline the conditions that direct pyruvate toward the following:
d. Glucose synthesis (gluconeogenesis)
In what tissues or organisms is each pathway present?