Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

22. Carbohydrate Metabolism

Pyruvate Oxidation

GOB Chemistry

22. Carbohydrate Metabolism

Pyruvate Oxidation

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4:20 minutes

Problem 11

Textbook Question

Pyruvate has three different fates. What are the three different molecules pyruvate is converted into? What conditions exist for the formation of each product?

Verified step by step guidance

Pyruvate is a key intermediate in cellular metabolism, and its fate depends on the cellular conditions. The three main molecules pyruvate can be converted into are lactate, acetyl-CoA, and ethanol. Let's explore each pathway and the conditions under which it occurs.

1. **Conversion to Lactate**: Under anaerobic conditions (lack of oxygen), pyruvate is reduced to lactate by the enzyme lactate dehydrogenase. This process regenerates NAD⁺, which is essential for glycolysis to continue. This occurs in muscle cells during intense exercise or in certain microorganisms.

2. **Conversion to Acetyl-CoA**: Under aerobic conditions (presence of oxygen), pyruvate is transported into the mitochondria and converted into acetyl-CoA by the enzyme pyruvate dehydrogenase. Acetyl-CoA then enters the citric acid cycle (Krebs cycle) for further energy production.

3. **Conversion to Ethanol**: In some microorganisms, such as yeast, pyruvate is converted into ethanol and carbon dioxide under anaerobic conditions. This process, known as alcoholic fermentation, involves two steps: (a) pyruvate is decarboxylated to acetaldehyde by the enzyme pyruvate decarboxylase, and (b) acetaldehyde is reduced to ethanol by alcohol dehydrogenase.

These three pathways highlight how pyruvate serves as a metabolic crossroads, with its fate determined by the availability of oxygen and the type of organism or cell involved.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Pyruvate Decarboxylation

Pyruvate decarboxylation is the process by which pyruvate, produced from glycolysis, is converted into acetyl-CoA. This reaction occurs in the mitochondria and is catalyzed by the pyruvate dehydrogenase complex. Acetyl-CoA is a crucial substrate for the Krebs cycle, linking glycolysis to aerobic respiration.

Lactic Acid Fermentation

Lactic acid fermentation is an anaerobic process where pyruvate is converted into lactic acid, primarily in muscle cells and certain bacteria. This occurs when oxygen is scarce, allowing for ATP production without the Krebs cycle. It helps regenerate NAD+, which is essential for glycolysis to continue.

Alcoholic Fermentation

Alcoholic fermentation is another anaerobic process where pyruvate is converted into ethanol and carbon dioxide, primarily by yeast. This process occurs in the absence of oxygen and is utilized in brewing and baking. It also regenerates NAD+, allowing glycolysis to proceed and produce ATP.

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