You Are Attempting to Determine Whether a Plant-Derived Processed Food

You are attempting to determine whether a plant-derived processed food sample (for example, a corn chip) contains material from a genetically modified organism (GMO). First, you crush the sample and attempt to extract DNA from it. Next, you perform PCR using two different sets of primers. One primer set will amplify a DNA sequence present in all plants. The second primer set will amplify a DNA sequence only found in GMO plants.
a. Why must you use both sets of primers for this experiment?
b. In addition to the test sample, you obtain a negative control sample (food material you are certain does not contain GMO material) and a positive control sample (food material you are certain does contain GMO material). You perform the DNA extraction on these three samples and then the PCR reactions with each of the two primer sets described above. Complete the following table with your expectations for this PCR reaction. $$\begin{array} { | l | l | l | l | } \hline \text { Lane } & { \text { PCR reaction } } & { \begin{array} { c } \text { Expect band? } \\\text { [non-GMO food] }\end{array} } & \begin{array} { c } \text { Expect band? } \\\text { [GMO food] }\end{array} \\\hline 1 & \text { Negative control - plant primers } & & \\\hline 2 & \text { Negative control - GMO primers } & & \\\hline 3 & \text { Test sample - plant primers } & & \\\hline 4 & \text { Test sample - GMO primers } & & \\\hline 5 & \text { Positive control - plant primers } & & \\\hline 6 & \text { Positive control - GMO primers } & & \\\hline\end{array}$$ c. You obtain the results shown in the panel below. What conclusions can you draw from these reaction results? Does this test sample contain genetically modified components? Why or why not?