What happens if we do not have enough oxygen present in the cell? So these types of conditions when we do not have oxygen are known as anaerobic conditions. And under anaerobic conditions, glycolysis is the only method by which we actually produce ATP. Remember, glycolysis can take place regardless of whether or not we actually have oxygen present in the cell. So glycolysis is the process, the first process of aerobic respiration, and it's the first process of anaerobic respiration as well. However, under anaerobic conditions, glycolysis is the only method by which we produce ATP molecules in the cell.