1.
BIO 2
Diploid cells have two copies of each type of chromosome. Draw out the process of mitosis in a diploid cell that has four chromosomes (total): two copies of chromosome 1 and two copies of chromosome 2. Use colored pencils to color the copies of chromosome 1 blue and the copies of chromosome 2 red so they can be easily distinguished from one another in your drawing.
Label each stage of mitosis and be sure to include drawings of the original parent cell (prior to mitosis) as well as the two daughter cells (that are produced following mitosis and cytokinesis).
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3.
2. Haploid cells (like yeast cells) have only one copy of each chromosome. On the top of the next page, draw out the process of mitosis in a haploid cell that has two chromosomes total: one copy of chromosome 1 (blue) and one copy of chromosome 2 (red). As in your drawing for question #1, be sure to include drawings of the original parent cell (prior to mitosis) as well as the two daughter cells (that are produced following mitosis and cytokinesis).
You have extracted DNA from various food sources (shown in column 3 of the table at the top of the next page) and set up the following PCR reactions, where the universal plant primers target a gene coding for a protein involved in photosynthesis and yield a 455 bp PCR product, and the GMO primers target two promoters commonly used in plant transgenes (the same ones targeted by the PCR primers in lab) and yield PCR products of similar size (about 215 bp).
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Reaction # Primer Set
1
2
3
Source of DNA
Universal plant primers Known GMO+ soybean sprouts
GMO primers Known GMO+ soybean sprouts
4
5
6
Universal plant primers Known GMO- raisins
GMO primers Known GMO- raisins
Universal plant primers Fritos brand corn chips
7
8
GMO primers Fritos brand corn chips
Universal plant primers Zanzibar papaya
GMO primers Zanzibar papaya
After PCR and gel electrophoresis, the gel looks like the one shown at the top of the next page.
1 2 3 4 5 6 7 8
DNA ladder
WELLS
600
450
250
200 a. Which of your PCR reactions were positive controls? Did they work?
Reactions 1, 2, 3, 5, and 7 were positive controls. All of them worked except for reaction 7. The Zanzibar papaya DNA extract should have yielded a PCR product with the universal plant primers but did not.
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b. Which of your PCR reactions were negative controls? Did they work?
Reaction 4 was a negative control. It did “work” because the PCR reaction was not productive. c. If any of the controls did NOT work, what do you think might have gone wrong? (List at least 3 possible explanations.)
Reaction 7 did not work. Possible explanations: (1) I did not perform the DNA extraction from the papaya correctly (2) I forgot to add one of the reagents to PCR reaction #7 (3) When I loaded the gel, I failed to get any of the sample into well 7.
4.
You may be able to think of other explanations.
The GMO+ primers used in lab are actually comprised of two different primer sets that target two different common plant transgenes. Knowing what you do about PCR, what must be true of these two primers sets in order for them to be “multiplexed” (used in the same PCR reaction) successfully? Explain. (A single sentence is sufficient!)
The PCR primers must all have approximately the same melting temperature so that the annealing temperature used in the reaction will work for both primer sets.
5. ANSWER MUST BE TYPED.
Using the internet, locate the website of at least one reputable organization that opposes transgenic plant technology. What argument(s) does this organization make against the use of transgenic plants? Write up your answer in your own words (don’t just cut and paste from the website, please) and reference the website using the following format:
Author. (Publication Date). Web page title. Retrieved Date (month/day/year) from URL
 Author: Usually found at the top or bottom of the web page. Look for: Author,
Compiler/Compiled by, Maintainer/Maintained by. If author is not available, begin your citation with the web page title.
 Publication Date: Usually found at the end of the document. Use the last update if available. Use the copyright date if available. If the month and day are given, include them.
If a publication date is not available, use n.d. (no date).
 Web Page Title: Give the title of the web page here. If you are citing a specific article within a larger web site, give the title of the article and the name of the larger web site.
 Retrieved date: the day, month and year that you originally accessed the page.
 URL: "Uniform Resource Locator" is the web address of your document. It is found at the top right corner of your printout or in the "Location" bar on your web browser. Take care in
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transcribing the URL. Copying and pasting is recommended. Whenever possible, the URL should take the reader directly to the document you are citing. If this is not possible, the URL should take the reader as close to the document as possible.
NO KEY – Many answers are possible.
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