Passage IV

A scientist tested the ability of 4 drugs to kill cancer cells.

Experiment 1

Permeability coefficients measure a drug's ability to enter a cell. The larger the permeability coefficient, the faster the drug enters a cell. The molecular mass, in atomic mass units (amu), and permeability coefficient, in centimeters per second (cm/sec), of the 4 drugs at 37°C were measured and are shown in Table 1.

Experiment 2

Equal numbers of cancer cells were put into flasks containing 5.0 mL of nutrient medium. The cells were incubated for 1 hour at 37°C with 1 of the 4 drugs shown in Table 2. A control consisted of cells incubated in medium without any drugs. The cells were washed to remove residual drug traces and grown on nutrient plates for 7 days. During this time, the cells reproduced, forming colonies which were then counted. Plates with more colonies were assumed to have more live cells at the end of the 1-hour incubation. Table 2 shows the number of colonies counted. The drug-free control showed 30 colonies.

Experiment 3

Cells were handled as described in Experiment 2 with two exceptions: all drugs were tested at the same concentration and incubation time was varied. Table 3 shows the number of colonies counted for Experiment 3.