After glycolysis, pyruvate enters the mitochondrion via what mechanism?

Pyruvate enters the mitochondrion through active transport mechanisms, which is why this choice is correct. After glycolysis, pyruvate is produced in the cytoplasm and must move into the mitochondrial matrix for further processing in the citric acid cycle. However, the concentration of pyruvate inside the mitochondrion is typically higher than that in the cytoplasm. This gradient necessitates an energy-consuming process for pyruvate to be transported into the mitochondrion, leading to the involvement of specific transport proteins that require energy, often supplied by the electrochemical gradient created by the proton pumps in the mitochondrial membrane.

Additionally, pyruvate transport is coordinated with the transport of protons, utilizing a protein complex that works symbiotically to ensure efficient entry for pyruvate into the mitochondrion. This process is essential for ensuring that pyruvate does not accumulate in the cytosol and can continue into aerobic respiration.

In contrast, passive diffusion would not require energy and typically occurs for small nonpolar molecules or gases. Facilitated diffusion also does not require energy but is specific for certain molecules and would not apply to pyruvate given its charged nature. Exocytosis refers to the process by which substances are released from a cell