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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

22. Carbohydrate Metabolism

Pyruvate Oxidation: Videos & Practice Problems

Video Lessons Practice Worksheet

Topic summary

Pyruvate oxidation is crucial in cellular respiration, determining the pathway based on oxygen availability. In aerobic conditions, pyruvate is transported to the mitochondrial matrix, where it is oxidized by the enzyme pyruvate dehydrogenase to form Acetyl CoA. This process reduces NAD⁺ to NADH and releases carbon dioxide. The Acetyl group from Acetyl CoA then enters the citric acid cycle, leading to ATP generation through oxidative phosphorylation. Understanding these metabolic pathways is essential for grasping energy production in cells.

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Pyruvate Oxidation Concept 1

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Pyruvate Oxidation Concept 1 Video Summary

Pyruvate oxidation is a crucial step in cellular respiration, occurring after glycolysis, where one glucose molecule is converted into two pyruvate molecules. This process takes place in the cytosol and is linear in nature. The fate of pyruvate is determined by the availability of oxygen in the cells. If oxygen is present, pyruvate undergoes further processing to form Acetyl CoA, which then enters the mitochondrial matrix for the Krebs cycle (also known as the citric acid cycle). This cycle is essential for the production of energy-rich molecules such as NADH and FADH₂, which are vital for the next stage of cellular respiration.

In the absence of oxygen, pyruvate is redirected towards fermentation, leading to anaerobic respiration. This pathway allows cells to generate energy without oxygen, although it is less efficient than aerobic respiration. The overall process of aerobic respiration can be summarized in four main stages: glycolysis, pyruvate oxidation, the Krebs cycle, and the electron transport chain (ETC) coupled with oxidative phosphorylation. Each of these stages plays a significant role in the complete oxidation of glucose, ultimately leading to the production of ATP, the energy currency of the cell.

In summary, the availability of oxygen is a key factor influencing the metabolic pathway of pyruvate, determining whether it will proceed towards aerobic respiration or fermentation.

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Pyruvate Oxidation Concept 2

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Pyruvate Oxidation Concept 2 Video Summary

In the presence of oxygen, pyruvate undergoes a crucial transformation during aerobic respiration. This process begins with the transport of pyruvate from the cytosol into the mitochondrial matrix. Here, pyruvate is oxidized by the enzyme pyruvate dehydrogenase, which is a type of dehydrogenase enzyme that facilitates oxidation reactions. The reaction can be summarized as follows:

$$\text{Pyruvate} + \text{NAD}^+ + \text{CoA} \rightarrow \text{Acetyl CoA} + \text{NADH} + \text{CO}_2$$

During this reaction, one molecule of NAD⁺ is reduced to NADH, and one carbon atom is released as carbon dioxide (CO₂). The pyruvate molecule, which contains a carboxyl group, interacts with coenzyme A (CoA) and NAD⁺ to produce Acetyl CoA, NADH, and CO₂. This transformation is essential for the subsequent steps of cellular respiration, highlighting the importance of oxygen availability in determining the fate of pyruvate.

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What is pyruvate oxidation and why is it important?

Pyruvate oxidation is a crucial step in cellular respiration that occurs in the mitochondrial matrix when oxygen is available. During this process, pyruvate, produced from glycolysis, is converted into Acetyl CoA by the enzyme pyruvate dehydrogenase. This reaction also reduces NAD⁺ to NADH and releases carbon dioxide. The Acetyl CoA then enters the citric acid cycle, leading to the production of ATP through oxidative phosphorylation. This step is essential for energy production in cells, as it links glycolysis to the citric acid cycle and ultimately to the electron transport chain, where the majority of ATP is generated.

What happens to pyruvate in the absence of oxygen?

In the absence of oxygen, pyruvate undergoes anaerobic respiration, leading to fermentation. Instead of being transported to the mitochondrial matrix for oxidation, pyruvate remains in the cytosol. In animal cells, it is converted into lactate by lactate dehydrogenase, regenerating NAD⁺ from NADH, which is essential for glycolysis to continue. In yeast and some bacteria, pyruvate is converted into ethanol and carbon dioxide. This process allows cells to produce ATP without oxygen, although it is much less efficient than aerobic respiration.

What enzyme is responsible for the oxidation of pyruvate?

The enzyme responsible for the oxidation of pyruvate is pyruvate dehydrogenase. This enzyme catalyzes the conversion of pyruvate into Acetyl CoA in the mitochondrial matrix. During this reaction, one molecule of NAD⁺ is reduced to NADH, and one molecule of carbon dioxide is released. Pyruvate dehydrogenase is a key regulatory point in cellular respiration, linking glycolysis to the citric acid cycle.

How is NAD⁺ involved in pyruvate oxidation?

NAD⁺ plays a crucial role in pyruvate oxidation as an electron carrier. During the conversion of pyruvate to Acetyl CoA by pyruvate dehydrogenase, NAD⁺ is reduced to NADH. This reduction involves the transfer of electrons from pyruvate to NAD⁺, forming NADH. The NADH produced then carries these high-energy electrons to the electron transport chain, where they are used to generate ATP through oxidative phosphorylation. Thus, NAD⁺ is essential for capturing and transferring energy during cellular respiration.

What are the products of pyruvate oxidation?

The products of pyruvate oxidation are Acetyl CoA, NADH, and carbon dioxide. During this process, pyruvate is converted into Acetyl CoA by the enzyme pyruvate dehydrogenase. One molecule of NAD⁺ is reduced to NADH, capturing high-energy electrons, and one molecule of carbon dioxide is released as a byproduct. The Acetyl CoA then enters the citric acid cycle, where it contributes to further ATP production through oxidative phosphorylation.