Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

33. The Organic Chemistry of Metabolic Pathways

The Citric Acid Cycle

Organic Chemistry

33. The Organic Chemistry of Metabolic Pathways

The Citric Acid Cycle

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Multiple Choice

Which two steps of the citric acid cycle produce CO₂?

1 and 3

3 and 4

2 and 4

2 and 3

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Verified step by step guidance

Understand that the citric acid cycle, also known as the Krebs cycle, is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate derived from carbohydrates, fats, and proteins into carbon dioxide.

Recall that during the citric acid cycle, carbon dioxide (CO2) is released as a byproduct in two specific steps.

Identify the steps in the citric acid cycle where decarboxylation occurs, which is the process of removing a carboxyl group and releasing CO2.

The first decarboxylation occurs when isocitrate is converted into alpha-ketoglutarate, releasing CO2. This is catalyzed by the enzyme isocitrate dehydrogenase.

The second decarboxylation occurs when alpha-ketoglutarate is converted into succinyl-CoA, releasing another CO2 molecule. This step is catalyzed by the enzyme alpha-ketoglutarate dehydrogenase.