1) Recognize the position in cell cycle for each of following mammalian cells as accurately as possible (that is, recognize the stage of mitosis, if the cell is in M phase.)

a) The cell has no cyclin B present, has mono-phosphorylated cdk1

b) Has no growth factor receptors on its surface

c) Cyclin B is present, spindle is present, chromatin is completed condensed

d) Cyclin B is absent, separase is active, kinetochore microtubules are shortening

e) The cell can be strongly labeled by adding the fluorescent deoxynucleoside triphosphates to its culture medium.

2) A frozen tube of the HeLa cells and also they were all in the similar stage of cell cycle when it has been harvested and frozen them.

a) First proposed a way in order to synchronize cells in one stage of the cell cycle.

b) Now explain an experiment which will enable you to find which stage of the cell cycle they were in when they were harvested and froze them.