What term describes the process of releasing energy from sugar molecules without oxygen?

The process described is known as anaerobic respiration, which refers to the way cells generate energy from sugar molecules in the absence of oxygen. During anaerobic respiration, glucose is partially broken down to release energy, resulting in byproducts such as lactic acid in animals or ethanol and carbon dioxide in yeast and some plants.

Understanding anaerobic respiration is critical because it occurs in environments where oxygen is limited or unavailable. This can happen in certain muscle cells during intense exercise when oxygen supply cannot meet demand, which leads to the production of lactic acid. Similarly, in fermentation processes, microorganisms like yeast utilize anaerobic respiration to produce energy, which is a vital concept in both microbiology and biotechnology.

In contrast, aerobic respiration requires oxygen and is a more efficient process for energy production, involving complete oxidation of glucose. Oxidative phosphorylation refers specifically to the stage in aerobic respiration where ATP is generated using the energy released from electrons transferred through the electron transport chain. Finally, cellular respiration is a broad term that encompasses both aerobic and anaerobic pathways of energy extraction, but the specific process of energy release from sugars without oxygen is uniquely defined as anaerobic respiration.