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Mitosis/ Chromosomes in Human Cells

HeLa cells (a strain of human cells cultured in the laboratory) have a mitotic cycle of about 24 hours, of which about 11 hrs is spent in G1, about 8 hrs in S, about 4 hrs in G2, and about 1 hr in mitosis. If you took a sample of HeLa cells from a culture, and looked at it through the microscope, in about what % of cells would you expect the chromosomes to be visible?

The answer is about 1 cell in 24, or 4.2%, would be expected to have visible chromosomes.

I have been doing this problem several times now and I can't figure out how to do it. I am so confused. Can you also explain the number of chromosomes you get from mitosis?

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The first part of your question is one sometimes examined in cell biology labs where mitosis (cell division) is being observed ( for an example and some explanations of key concepts see http://dbs.umt.edu/courses/biol101S04/labs/Wyrick_s04/11_cell_cycle.htm). An assumption made during these exercises is that, given a statistically sufficient sample of the total cell population, the number of cells you see in a given phase is equal to the time they spend in that phase. Since the total time required for cell division to take place in the HeLa cells is 24 hrs, and the length of time cells spend in mitosis is one ...

Solution Summary

This solution provides assistance determining at what percentage of cells one could expect the chromosomes to be visible from a sample of HeLa cells form a culture, and explains the number of chromosomes you get from mitosis.