One of the main consequences of the formulation on the level of the individual cell is that, if one keeps on following the daughter lineage of a cell, the daughter cell cycle approaches an attractor resembling the cycle of the smallest cell in the culture (Fig 2A). A smallest cell exists because the START transition can only be made for cell sizes satisfying condition (2), which has a minimum for bounded values of spf (Note that we had spf;SPMlt;;SPMlt;1). Cells which pass this stage at the smallest size will produce the smallest buds which again will pass START at the same smallest size. A heuristic argument for the convergence to this smallest cell attractor is the following. For cell cultures in balanced growth, both mass and cell number are growing at the same rate. Suppose that after division under all circumstances both daughter and mother are bigger than that of the mother at the beginning of that cycle, then the overall mass will be growing faster than cell number. So a daughter cannot be bigger than its mother at the beginning of the cycle in cultures with balanced growth.
Figure 2: Trajectories of the smallest daughter cell (A) and one of the largest
mother cells (B). The mass at the beginning of the cell cycle was 1.08 for
the daughter and 23.4 for the mother. The following parameter values were
used: 
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The result of having a single cell-cycle attractor is not general but seems to hold for all parameter values which give rise to biologically acceptable dynamics, i.e. in the cell cycle of the smallest cell only one signal for START is given.
If we follow the mother lineage of this smallest cell we see that, as observed in experiments, mother cells get bigger after each division while they gain the mass accumulated in the pre-START period. Finally a point will be reached where either the pre-START period reduces to zero (all consecutive mother cells are of equal size) or where the cells get stuck in a state in which both MPF and SPF are high ( the mother will never divide) (Fig 2B). Cells chemically stuck are still growing since we did not put a limit to growth based on cell cycle stage.