Final answer:
Leopard frogs and other organisms can produce ATP without oxygen through fermentation, which includes glycolysis and the conversion of NADH to NAD+ by reducing pyruvate to lactate or ethanol.
Step-by-step explanation:
Leopard frogs, like many organisms, can produce adenosine triphosphate (ATP) without oxygen through a process called fermentation. This process is important for situations where oxygen levels are too low to support aerobic respiration.
Cells will undergo glycolysis, which does not require oxygen and produces a small amount of ATP. If more ATP is needed and oxygen is not available, cells will then convert NADH back into NAD+ by transferring electrons to pyruvate, producing lactic acid or ethanol, depending on the type of fermentation. This allows glycolysis to continue producing ATP.
In the case of anaerobic respiration, certain organisms like some bacteria and yeasts use alternative electron acceptors other than oxygen to generate ATP. Humans make use of these processes industrially to create products such as yogurt, bread, and alcoholic beverages, and our muscle cells also resort to lactic acid fermentation during intense exercise when oxygen is scarce.