What effect do both metabolic acidosis and alkalosis have on metabolic enzymes?

Metabolic acidosis and alkalosis both create an imbalance in the pH levels of the bodily fluids. Enzymes, which are biological catalysts essential for metabolic reactions, operate optimally within a specific pH range. When the pH deviates significantly from this range—either becoming too acidic or too alkaline—the structure and function of enzymes can be adversely affected.

In the case of metabolic acidosis, increased hydrogen ion concentration leads to a decrease in pH, which can denature enzymes or alter their active sites, reducing their efficiency and activity levels. Similarly, in metabolic alkalosis, the reduction in hydrogen ion concentration and increased pH can also disrupt enzyme structure and function, impairing their activity. As a result, both conditions generally lead to a decrease in the speed of metabolic reactions, consequently slowing down metabolic processes.

This is why the correct answer indicates that both metabolic acidosis and alkalosis decrease the speed of metabolic enzymes. In contrast, choices implying an increase in enzyme activity or no effect would not accurately reflect the biochemical realities of how pH influences enzyme kinetics.