Assume That You Were Growing Cells in Culture and Had

Essay

Assume that you were growing cells in culture and had determined the cell-cycle time to be 24 hours. You introduce ³H thymidine and prepare autoradiographs of metaphase chromosomes after 48 hours. Of the chromosomes that are labeled, you expect two classes: one class that had completed one S phase in the label, and a second class that had completed a cellular division and an additional S phase in the label. Draw the DNA (double-stranded) labeling pattern for each chromosome that you would expect to find in these two types of metaphase chromosomes. (Use a broken line {- - -} for labeled single strands of DNA and a solid line for unlabeled single strands of DNA.)
(a) metaphase chromosome having replicated once in label
(b) metaphase chromosome having gone through two S phases in label