In the absence of oxygen, cellular respiration cannot occur. Cellular respiration is the process by which cells convert the chemical energy of glucose into adenosine triphosphate (ATP), the primary source of energy for the cell. Without oxygen, the final stage of cellular respiration, known as oxidative phosphorylation, cannot take place.

As a result, the cell must rely on alternative pathways to generate ATP, such as anaerobic glycolysis. Anaerobic glycolysis is a less efficient process that produces significantly less ATP compared to cellular respiration. Therefore, the cell will experience a severe energy deficit, leading to the impairment of various cellular functions and ultimately cell death.

Moreover, the accumulation of pyruvate, a product of anaerobic glycolysis, can cause a decrease in the cell's pH, leading to cellular acidosis. This acidic environment further disrupts cellular processes, exacerbating the overall impact of oxygen deprivation.

In summary, the absence of oxygen in the cell results in the cessation of cellular respiration, leading to energy depletion, accumulation of waste products, and cellular dysfunction, eventually resulting in cell death.