Final answer:
Fermentation is an anaerobic process that allows energy production from glucose without the use of oxygen, enabling the continued production of ATP when oxygen is not available.
Step-by-step explanation:
The process in which energy is derived from the bonds of the glucose molecule but in which spent electrons do not end up combining with oxygen is known as fermentation. This process is crucial for making ATP without oxygen and is considered anaerobic.
While glycolysis, which also does not require oxygen, is the first step in the breakdown of glucose for energy, it leads to only a small amount of ATP production. In the absence of oxygen, cells can continue to produce ATP through fermentation, which allows the recycling of NAD+ from NADH, enabling glycolysis to continue.