AbstractMany changes that occur in a cell during the cell cycle can be demonstrated in synchronous cultures and can reveal dimensions of cell metabolism not attainable by the study of balanced growth of asynchronous populations in batch cultures or the steady state in chemostat cultures. The release of14CO2from specifically labeled glucose by phased (continuously synchronized) cultures follows a characteristic pattern (profile) that depends upon the stage in the cell cycle and the period of labeling used. Successive profiles throughout a cycle showed differences that were altered under different nutrient‐limiting growth conditions. Profiles obtained with glucose‐1‐14C, glucose‐2‐14C, glucose‐3,4‐14C, and glucose‐6‐14C and phased cells ofCandida utilisunder N‐, P‐, and C‐limited growth demonstrated the variable character of the metabolic activity that occurred in the cells while contour changes within the profiles across the cycle indicated possible correlations with activities of the hexose monophosphate, Embden‐Meyerhof‐Parnas, and tricarboxylic acid cycle pathways during the cell cycle. The basis of these changes and their use as elementary parameters for study of problems of physiological c