Carbon dioxide (\(\mathrm{CO_2}\)) is released during which of the following stages of cellular respiration?

• A. Electron transport chain
• B. Citric acid cycle (Krebs cycle)
• C. Glycolysis
• D. Oxidative phosphorylation

Answer: (B)

Verified step by step guidance

1. Understand the stages of cellular respiration: Glycolysis, Citric Acid Cycle (Krebs Cycle), and Oxidative Phosphorylation (which includes the Electron Transport Chain). Each stage has specific roles in energy production and byproduct release.
2. Recall that carbon dioxide (\(\mathrm{CO_2}\)) is a byproduct of the breakdown of carbon-containing molecules. This occurs when carbon atoms are removed from molecules in the form of \(\mathrm{CO_2}\) during metabolic reactions.
3. Focus on the Citric Acid Cycle (Krebs Cycle): This stage occurs in the mitochondrial matrix and involves the oxidation of acetyl-CoA. During this process, carbon atoms are released as \(\mathrm{CO_2}\) when citrate is broken down into smaller molecules.
4. Eliminate other options: Glycolysis occurs in the cytoplasm and does not produce \(\mathrm{CO_2}\), as it only breaks glucose into pyruvate. The Electron Transport Chain and Oxidative Phosphorylation involve the transfer of electrons and production of ATP, but they do not release \(\mathrm{CO_2}\).
5. Conclude that the Citric Acid Cycle (Krebs Cycle) is the stage of cellular respiration where \(\mathrm{CO_2}\) is released as a byproduct of the oxidation of acetyl-CoA.