Q1: Recognize the position in the cell cycle for each of the given mammalian cells as precisely as possible (that is, identify the phase of mitosis, if the cell is in M phase.)
a) The cell consists of no cyclin B present, has mono-phosphorylated cdk1
b) Has no growth factor receptors on its surface.
c) Cyclin B is present, the spindle is present and chromatin is completed condensed.
d) Cyclin B is absent, separase is active, and kinetochore microtubules are shortening.
e) The cell can be strongly labeled by adding up fluorescent deoxynucleoside triphosphates to its culture medium.
Q2. I handed you a frozen tube of HeLa cells and tell you that they were all in the same phase of the cell cycle when I harvested and froze them.
a) At first propose a way to synchronize the cells in one phase of the cell cycle.
b) Now illustrate an experiment which will permit you to find out which phase of the cell cycle they were in when I harvested and froze them.