Final answer:
In the yeast Saccharomyces pombe, a kinase is necessary to phosphorylate and fully activate cyclin-dependent kinases (Cdks), which is crucial for cell cycle advancement.
Step-by-step explanation:
The Cdk activating kinase in the yeast Saccharomyces pombe is essential for cell cycle progression. Cyclin-dependent kinases (Cdks) must bind to a cyclin protein and be phosphorylated by another kinase to become fully activated, as described in several figures and chapters related to the cell cycle and mitosis. In yeasts like Saccharomyces pombe, there are various types of kinases that play a role in cellular communication, and although the specific Cdk activating kinase isn't directly named here, the concept that a kinase is required to phosphorylate and activate Cdk is fundamental to understanding the cell cycle.