|Another characteristic of most yeast, including
S. cerevisiae, is that they divide by budding, rather than by binary fission.
A small bud emerges from the surface of the parent cell and enlarges until
it is almost the size of the parent.
While this is happening the chromosomes of the
parent replicate. At mitosis, when the nucleus divides, one of the nuclei
is transferred to the bud, and then the two cells separate. Both haploid
and diploid yeast cells divide by budding. The cell division cycle begins
with a single, unbudded cell. This cell buds, the bud grows to nearly the
size of the parent cell, the nucleus divides, and the two cells separate
into two unbudded cells. The cycle then begins again for both of the cells.
The result is an exponential increase in the number of cells with a doubling
time equal to the mean cell division cycle time. This varies with the strain,
the growth medium, and the temperature, but can be as short as one hour.
At this rate, a single cell can grow into a barely visible colony in one