You are interpreting data on a DNA chip or microarray. You expose the chip to a mixture of two cDNA populations: one from cells that were not treated with a glucocorticoid hormone (untreated controls; labeled with a red fluorescent dye)and a population from cells that were treated with glucocorticoid hormones (glucocorticoid-treated; labeled with green fluorescent dye). You look at a spot on the chip representing the gene for phosphoenolase, a gene that is turned off by glucocorticoid treatment, but is expressed in control, untreated cells. What color should the spot representing the phosphoenolase gene be?
A)red
B)green
C)yellow
D)no color, the spot is not labeled
E)brown

Question

Quizplus · Accepted Answer

Since the gene for phosphoenolase is only expressed in untreated control cells, the spot representing this gene should be labeled with the red fluorescent dye, indicating that it is not expressed in the green-labeled glucocorticoid-treated cells.

You Are Interpreting Data on a DNA Chip or Microarray