What effect does a lack of oxygen have on cellular respiration?

A lack of oxygen significantly impacts cellular respiration by halting the electron transport chain, which is crucial for aerobic respiration. In the absence of oxygen, the electron transport chain cannot function, as oxygen is the final electron acceptor needed for the process to proceed. When this chain is disrupted, cells are unable to produce ATP efficiently through aerobic means.

As a result, cells switch to anaerobic respiration to generate ATP. This process can occur through fermentation pathways, depending on the type of cell. For example, muscle cells can perform lactic acid fermentation, whereas yeast can undergo alcoholic fermentation. Both pathways allow for limited ATP production while regenerating the necessary molecules (like NAD+) that ensure glycolysis can continue, though they yield far less energy compared to aerobic respiration.

The other choices imply effects that do not align with the physiological responses of cells to low oxygen conditions. Thus, the transition to anaerobic respiration becomes the primary pathway in an oxygen-deprived environment.