Typical culture-density profile of a fermentative batch culture of S. cerevisiae. Black line: A schematic representation of the increase in cell number and cell density of a batch culture of Saccharomyces cerevisiae inoculated in rich medium containing a rapidly fermentable sugar, e.g. glucose, as a carbon source. After a short adaptive lag phase, yeast consumes the sugar during the exponential fermentative growth phase. When the sugar becomes limiting, yeast cells enter the diauxic shift and reprogram their metabolic capacity from fermentation to respiration. In the post-diauxic growth phase, the cells consume ethanol, acetate and other products of the initial fermentation as carbon source. Finally, when these carbon sources are exhausted, the cells enter a quiescent state, the stationary phase (G0), with the ultimate goal of surviving the starvation period. Gray line: When exponentially growing yeast cells are transferred to medium containing glucose but missing an essential nutrient such as nitrogen or phosphate, they arrest growth and enter the G0 state due to nutrient deprivation.