Before entering the Krebs cycle, pyruvate is converted toMultiple ChoiceH2O and CO2.glucose.acetic acid.acetyl CoA.ATP.

To determine what pyruvate is converted to before entering the Krebs cycle, we need to consider the metabolic pathway it undergoes.

Breakdown of the Problem

1. Identify Key Concepts: The conversion of pyruvate to acetyl CoA is a crucial step that links glycolysis and the Krebs cycle.
2. Biochemical Transformation: Pyruvate undergoes decarboxylation, where a carbon atom is removed and released as CO2.

Relevant Concepts

• Pyruvate: A three-carbon molecule produced during glycolysis.
• Acetyl CoA: A two-carbon molecule that enters the Krebs cycle.
• The transformation from pyruvate to acetyl CoA is catalyzed by the pyruvate dehydrogenase complex.

Analysis and Detail

1. Pyruvate (C3H4O3) loses one carbon in the form of carbon dioxide (CO2), resulting in the formation of acetyl CoA (C2H3OCoA).
2. This conversion is significant as acetyl CoA is a key substrate for the Krebs cycle, allowing for the continuation of cellular respiration.

Verify and Summarize

• Pyruvate does not convert to glucose or H2O directly in this step.
• Acetyl CoA is produced from pyruvate, enabling the Krebs cycle to proceed.
• ATP is generated during glycolysis, but not directly from the conversion of pyruvate to acetyl CoA.

Final Answer

Pyruvate is converted to acetyl CoA before entering the Krebs cycle.