Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

3. Energy & Cell Processes

Krebs Cycle

Anatomy & Physiology

3. Energy & Cell Processes

Krebs Cycle

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Multiple Choice

How many molecules of carbon dioxide are released during one turn of the citric acid cycle?

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Verified step by step guidance

Understand the citric acid cycle: 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 acetyl-CoA derived from carbohydrates, fats, and proteins into carbon dioxide and chemical energy in the form of ATP.

Identify the key steps in the cycle where carbon dioxide is released: During the citric acid cycle, carbon dioxide is released in two specific steps. These occur during the conversion of isocitrate to α-ketoglutarate and the conversion of α-ketoglutarate to succinyl-CoA.

Examine the chemical reactions: In the first reaction, isocitrate is oxidized to α-ketoglutarate by the enzyme isocitrate dehydrogenase, releasing one molecule of carbon dioxide. In the second reaction, α-ketoglutarate is converted to succinyl-CoA by the enzyme α-ketoglutarate dehydrogenase, releasing another molecule of carbon dioxide.

Count the total number of carbon dioxide molecules released: Since each of these reactions releases one molecule of carbon dioxide, a total of two molecules of carbon dioxide are released during one turn of the citric acid cycle.

Summarize the process: The citric acid cycle involves multiple steps, but specifically, two steps release carbon dioxide, resulting in the release of two molecules of carbon dioxide per cycle turn.