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Journal 7

How Cells Divide
To solve the problem below, you must write a clear and convincing justification for accepting one of the possible answer choices as the best or most appropriate and for rejecting each of the other choices as less appropriate. Your reasons for rejecting choices are just as important as your reasons for choosing the best answer.
A student observed a cell under a microscope just before mitotic division. This cell contained 18 chromosomes. Some time later, the student observed the resulting two cells and noted that one cell contained 19 chromosomes and the other contained 17 chromosomes. Apparently, a malfunction had occured during the mitotic process. Which of the following is the most likely explanation of this malfunction?
1
 Cytokinesis failed to occur at the end of telophase.
2
 Two of the chromosomes failed to line up in metaphase.
3
 Metaphase preceded anaphase in this cell division
4
 In one chromosome, the chromatids failed to seperate in anaphase, but seperated at some later time.
5
 The spindle apparatus on one side of the cell was not functional.