Abstract
Changes in the phosphorylation of Chlorella cells during the life cycle the aulotrophic and micotrophic synchronous culture were followed under the light and dark. 1. In the autotrophic culture of Chlorella the amounts of esterified phosphate compounds of the algal cell under the light increased during the growing period and decreased strikingly in the ripening period showing a peak at the $L_1$ i/-cell stage. 2. TRhe amount of total esterified phosphate compounds of the cell under the dark, however, decreased during the growing period and then kept fairly constnat during the ripening nad division periods showing the greates activity of the oxidative phosphorylation in the early growing stage. 3. It is presumed that the energy requirement of the dividing algal cell in the autotrophic culture is fulfilled prior to the nuclear division mostly by the photosynthetic phosphorylation. 4. In the mixotrophic culture, the amount of esterified phosphate compounds of the algal cells under the light increased during the growing period and decreased during the late ripening and early division periods showing a peak in the $L_2$-cell stage as in the case of the phosphorylation under the dark. 5. The phosphorylation of the fell grown in the glucose medium is more active under the dark than under the light in the stages of the growing and early ripening periods. 6. It is considered that the excess glucose in the algal cell not only promotes the oxidative phosphorylation but also inhibits the photosynthetic phosphorylation of the cell. 7. It is presumed that the energy requirement of the dividing algal cell in the glucose medium is fulfilled prior to the nuclear division by the combined action of oxidative and photosynthetic phosphorylation, mostly by the oxidative phosphorylation.