Question

Study the data in the histograms. (a) Which axis indirectly shows the relative amount of DNA per cell? Explain your answer. (b) In the control sample, compare the first peak in the histogram (in region A) to the second peak (in region C). Which peak shows the population of cells with the higher amount of DNA per cell? Explain. (For additional information about graphs, see the Scientific Skills Review in Appendix F.)

Short answer

(a). Axis showing the amount of fluorescence per cell indirectly shows the relative amount of DNA per cell.

(b) The first peak in the histogram in region A is higher than the second peak (in region C). In interval A, more cells are observed that have fluorescence compared to interval C.

(c) The first peak in inhibitor-treated cells in interval A shows the population of cells having a higher amount of DNA per cell.

Step-by-step solution

Step 1: Histogram

A histogram is the method of data representation in the form of graphs. A horizontal axis shows the range of the number of variables, and the vertical axis shows the amount of data in that range.It involves the number of rectangles that represent some data.

The base of the rectangle represents the interval between different classes, and the height represents the frequencies of classes. Here variable number represents the fluorescence per cell.

Explanation for part (a)

The amount of DNA is shown by the X-axis that indicates the amount of fluorescence per cell because DNA is bound with the fluorescent chemical.After running this DNA sample at the cytometer, the fluorescent level of the cell can be determined.

Explanation for the answer (b)

In the control experiment, inhibitors are absent, so cells are dividing at the normal pace, and DNA is replicated, so the number of cells having fluorescence is increased with time. In interval A, the number of cells is more having the level of fluorescence in comparison to interval C.

Explanation for the answer (c)

When cells are treated by the inhibitor, they arrest to divide, and a number of cells with a higher amount of DNA is present in interval A.

When the mammalian cell culture is treated with an inhibitor, the cells stop to divide, and the number of cells containing an increased amount of DNA is lowered with time.