Before entering Krebs's cycle, the pyruvate is first decarboxylated and oxidized into:
Correct answer: D. Acetic Acid
- A. Alpha Ketoglutaric Acid
- B. Citric Acid
- C. Glyceric Acid
- D. Acetic Acid
Explanation
The statement you've provided is partially correct. Before entering the Krebs (citric acid) cycle, each pyruvate molecule, which is a product of glycolysis, undergoes a process called pyruvate decarboxylation. This occurs in the mitochondria. However, the resulting product is not directly acetic acid, but rather acetyl-CoA (acetyl coenzyme A). The conversion of pyruvate to acetyl-CoA involves two main steps: Decarboxylation: One of the three carbon atoms in pyruvate is removed in the form of carbon dioxide (CO2), leading to a two-carbon molecule called acetyl group. Oxidation: The remaining two-carbon acetyl group is oxidized, and the electrons are transferred to NAD+ (nicotinamide adenine dinucleotide), forming NADH. The oxidized acetyl group is then combined with coenzyme A to form acetyl-CoA.
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About Bioenergetics
Cellular respiration explains how cells release energy from glucose through glycolysis, the link reaction, Krebs cycle and electron transport chain. It includes ATP production, substrate-level and oxidative phosphorylation, aerobic versus anaerobic respiration, and the roles of mitochondria, oxygen and fermentation in energy transfer.
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