The growth of single cells. II. Saccharomyces cerevisiae

• 1.1. Measurements were made of the growth in dry mass and volume of single cells of the budding yeast Saccharomyces cerevisiae. Dry mass was measured by an integration method with an interference microscope, and volume was measured from photographs.
• 2.2. The growth in dry mass was linear for each budding cycle. The combined system of mother cell plus bud grows in dry mass at a constant rate from 20 minutes after the appearance of the bud until 20 minutes after the appearance of the next pair of buds. It is concluded that dry mass growth is linear for most of each cell generation. This result is similar to what was found earlier in the fission yeast Schizosaccharomyces pombe and lends support to the hypothesis that synthesis is controlled by centres or particles, perhaps microsomal, which remain constant until division, when they double and partition themselves between two daughter cells.
• 3.3. The curve for volume growth is approximately sigmoid.
• 4.4. The cell concentration fluctuates cyclically with a maximum about 20 minutes after budding, and a minimum about 40 minutes before budding.