Streptococci obtain energy primarily by fermenting sugars to which acid?

Streptococci obtain energy primarily by fermenting sugars to which acid?

• A. Formic acid
• B. Lactic acid
• C. Succinic acid
• D. Valeric acid

Answer: (B)

Streptococci are lactic acid bacteria that generate energy mainly through fermentation to lactic acid. In the absence of oxygen, they funnel sugars through glycolysis to produce pyruvate, and then lactate dehydrogenase converts pyruvate to lactic acid, regenerating NAD+ so glycolysis can continue and ATP can be made. This homolactic fermentation produces lactic acid as the primary end product, which is why lactic acid is the correct choice. Other acids listed are not typical end products of streptococcal fermentation, reflecting different bacterial metabolic pathways.

Streptococci are lactic acid bacteria that generate energy mainly through fermentation to lactic acid. In the absence of oxygen, they funnel sugars through glycolysis to produce pyruvate, and then lactate dehydrogenase converts pyruvate to lactic acid, regenerating NAD+ so glycolysis can continue and ATP can be made. This homolactic fermentation produces lactic acid as the primary end product, which is why lactic acid is the correct choice. Other acids listed are not typical end products of streptococcal fermentation, reflecting different bacterial metabolic pathways.