GMO Student Guide Worksheet on Background information due day of Lab 1


Be prepared for a GMO Lab quiz!


What is the benefit of using GMO plants with Bacillus thuringiensis?


Name 2 ways to identify GMO crops from the grocery store?


Why use 35 S promoter for cauliflower mosaic virus (CaMV352) and the terminator for nopaline synthase gene for Agrobacterium (NOS)?




What would be the purpose in using photosystem II chloroplast gene in this experiment?


What is (are) the controls used in this lab? Why these?



How do you genetically modify a crop? : List the basic steps







Draw a diagram of an engineered gene. Why do we use these?





List and briefly describe 3 methods for inserting gene into plants:









Are any of the above methods efficient? Do we need them to be? Why or why not?


What is InstaGene Matrix? Why use it?


What are the primers? What are they used for?



Lesson 1 Extraction of DNA From Food Samples

Focus Questions

1. How can you test a food to find out if it contains material derived from a genetically

modified organism (GMO)?




2. In what organelles is plant DNA located?


3. Many foods containing GM crops are highly processed. Can you suggest how DNA from whole plants may differ from that extracted from processed foods, e.g., corn chips, cornmeal, etc.?





4. What molecules are present in the cell that might interfere with DNA extraction?


5. Why do you also perform analysis on food that is known to be a non-GMO food control?



6. Why was the non-GMO food control prepared prior to your test food sample?



Lesson 2

Focus Questions

1. What chemicals and molecules are needed for PCR, and what is the function of each component?


2. Examine the 150 base promoter sequence below.








Write in the sequence of the complementary strand and mark the 3’ and 5’ ends of the

complementary strand.


Remembering that DNA polymerases can only add nucleotides to the 3’ end of DNA,

design a forward primer and a reverse primer, each 10 bases long, to amplify a target

sequence of the DNA that is at least 100 bp long. Write the sequence of the primers below,

with their 3’ and 5’ ends indicated. Also indicate on the sequence above which strand they

are complementary to (will anneal to).

Forward primer sequence:


Reverse primer sequence:


4. Why are you performing two PCR reactions on each DNA sample?



5. What is the purpose of the GMO-positive control DNA?



Lesson 3

Focus Questions

1. Why did you resolve your PCR products by electrophoresis?


2. Explain why DNA fragments separate according to size in an electrophoresis gel.


3. Why do you need a molecular weight ruler alongside your samples?


4. What results do you expect in each lane? Fill in the chart below.


Expect band Write down your prediction (Hypothesis)

Lane Sample (Yes, No, Don’t know)?

_____ 1 Sample 1: Non-GMO food control with plant primers

_____ 2 Sample 2: Non-GMO food control with GMO primers

_____ 3 Sample 3: Test food with plant primers

_____ 4 Sample 4: Test food with GMO primers

_____ 5 Sample 5: GMO positive control DNA with plant primers

_____ 6 Sample 6: GMO positive control DNA with GMO primers



After you see your results:

Lesson 4

Focus Questions

1. What was your test food?


2. Did your test food generate a 200 bp band with GMO primer (lane 4)?


3. What does this tell you about the GMO status of your food?



4. What other information do you need to confirm the GMO status of your sample?



5. How do the results of your other five PCR reactions help support or undermine your result for your test food?


6. If you were to repeat the procedure what laboratory practice might yield better results?