Consider This 12.1 Fiftieth Anniversary of DNA
The "discovery" of DNA in 1953 really indicates the year that Watson and Crick elucidated its helical structure. Use the Web to create a timeline marking the critical stages of development of our understanding about DNA structure and function. The benchmarks are often recognized by awards like the Nobel Prizes in physiology or medicine and chemistry.

Consider This 12.9 Checking All Bases
The structural features of a DNA molecule are more apparent if you can look at them in 3-D. This interactive animation will take you though several different views of DNA and its structural components.
a. How is a 3-D structure of DNA shown at that site similar to the one shown in the text? How is it different?
b. Look carefully at the structures of the four bases that make up DNA. What are their common structural features? How do they differ?
c. Look again at the large DNA molecule. Can you find the bases? How are they aligned?

Consider This 12.15 The Human Genome Project
In 2000, the Human Genome Project completed the sequence for all of the base pairs at least to the level of a "rough draft." What were some of the problems with the early version? Are there any ways to know if there were mistakes? Since 2001 scientists have completed the genetic maps of various species—the thale cress plant (a weed), the bacterium that causes cholera, and more recently (in 2005) the dog and the chimpanzee. Are any of these accomplishments useful to the sequence data for humans?

Consider This 12.16 Going for the Green
The text pointed to the EPA's Presidential Green Chemistry Award program several times. Use the Web to research the past winners of these awards. Select one of the winners dealing with biochemistry and write a short report describing the process or product that deserves this green award. Be sure to explain the benefits of the new process over existing ones. Be prepared to present your report to the class.

Consider This 12.17 Curious Corn

Starlink corn is a bioengineered plant that achieved notoriety. Starlink was never approved for human consumption, in part, because government regulatory agencies were cautious about effects on humans. Although it has no known deleterious effects, the concern was that people who were not normally allergic to corn would develop allergic reactions due to the bacterial protein engineered into it. Although Starlink was only approved for animal use, it accidentally found its way into the human food chain—into several brands of taco shells, for example.

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In the summer of 2001, the U.S. Centers for Disease Control and Prevention performed some carefully controlled experiments looking for antibodies that would have been produced by a set of individuals (in a true allergic reaction) who claimed an adverse effect from Starlink corn. Use the Web to find the results of this study. Is there any cause for alarm?

Consider This 12.18 Turning Over a New Leaf
The New Leaf Superior potato has been genetically engineered to produce its own insecticide. This gives the potato the ability to resist attack by potato beetles, destructive insects that cause significant damage to potato crops. You may have already eaten some of these potatoes without even knowing it, for they do not have to be labeled as a food produced through biotechnology.
a. Identify some of the benefits and risks associated with genetically engineered potatoes.
b. Would you knowingly eat potato chips made from New Leaf potatoes? Explain the reasons for your opinion.

Consider This 12.19 EU Moratorium on GM Foods
In the summer of 2003, the European Union (EU) adopted two proposals to help calm European "Frankenfood" concerns. The first proposal established a system to trace and label genetically modified products. The second proposal regulated the marketing and labeling of food and feed products derived from GM organisms. Six EU countries have placed a moratorium on the cultivation of GM crops. However, the United States along with Canada, Argentina, and Egypt filed suit through the World Trade Organization alleging that the moratorium is politically motivated. Use the resources of the Web to check the status of the European Union's moratorium on genetically modified foods. Develop a list of pro and con arguments.

Consider This 12.20 The Frankenfood Frenzy
Opposition to GM foods was a major theme of protesters at the 2005 World Trade Organization meeting in Hong Kong, China (Figure 12.20). A petition opposing the WTO trade dispute over GM food filed by the U.S., Argentina, and Canada, signed by over 135,000 people from over 100 countries and more than 740 organizations representing 60 million people was delivered to the WTO director. Search the Web to find out the allegations in the trade dispute and describe recent articles about current developments in the controversy.

Consider This 12.21 Cloning Clinics
Plans to develop human cloning clinics have been announced in the last several years. What risks and benefits are associated with such clinics? Has such a clinic been completed at this time, and are we closer to the stage presented in the chapter opener? Write a short report detailing your answers to these questions.