mitosis time?

Question

Today a lab was done where we counted how many cells were in each phase of mitosis under a microscope. We then used this to determine how long each phase of mitosis took.

My question is: how can the amount of cells in each phase accurately represent how long each phase of mitosis takes? I realize that more cells equals more time, but why??

thanks

Answer 1

It's based on probability. The longer a particular stage lasts, the more likely that when the process is stopped in, for example, a root tip, more cells will be in that stage.