Author(s): Michael S. Pritchard, Department of Philosophy, Western Michigan University & Theodore Goldfarb, Department of Chemistry, State University of New York at Stony Brook
NOTE: This contribution appeared as a featured resource in the online and printed issues of ENC Focus: A Magazine for Classroom Innovators Vol. 8 no.3, published by the Eisenhower National Clearinghouse for Mathematics and Science Education-ENC.
Steven Angell and Marcia Brandeau, Longwood High School, Middle Island
James Baglivi and Mary Loesing, Shoreham-Wading River High School, Shoreham
Theresa Dana, Deer Park High School, Deer Park
Jack Waszmer, Paul Gelinas Junior High School, Setauket
Back to Top
Instructions for the Teacher. This lesson is designed to explore several common ethics/values issues related to the behavior of research scientists, while reinforcing students' understanding of the relationship between the structure of the DNA molecule and the biology of protein synthesis. It was inspired by the video The Race for the Double Helix55, which is a dramatization of the efforts of James Watson, Francis Crick, Rosalind Franklin, Maurice Wilkins and other scientists that led to the discovery of the structure of DNA. The video is, in turn, based on the book The Double Helix, by James Watson56.
The complete activity requires a minimum of four forty-minute class periods. It should be used after students have learned about the structure of DNA, the relationship between DNA and messenger RNA (mRNA), and the mechanism of synthesis of proteins using mRNA.
At the beginning of the lesson, the class is divided into groups of four students each representing a "research team." The objective of these teams is to win a "bonus" by deciphering a coded message. This is achieved by first transcribing a DNA segment, given to the team, into mRNA, determining the amino acid sequence that is coded on the mRNA, and then using a code that assigns each amino acid to a letter or other element of sentence structure.
No single research team is given enough information to decipher the entire message. Each team is given instructions on how to interact with the other teams in an effort to win the bonus. Some of the teams are instructed to behave in a collaborative manner, sharing their information. A second set of teams is told to act in a highly competitive manner, keeping their own results to themselves while aggressively attempting to obtain data from the others. One team is instructed to work independently and methodically in an effort to solve the problem on its own.
The following instructions are based on an assumed class size of 24. The six four-person research teams will be labeled Groups A, B, C, D, E and F. Groups A, B, and C will be instructed to behave as "collaborator" teams. Groups D and E will be told to behave as aggressive "competitors." Group F will be the "independent," methodical research team. (In classes of larger or smaller size, some, or all of the groups can be increased to five or decreased to three students. Alternatively, the number of collaborator or competitor groups can be increased or decreased.)
The first group that brings the correct message to the teacher wins the bonus. That message is "CONGRATULATIONS! YOU ARE THE WINNER. THE BONUS IS YOURS!"
The segments of DNA given to each of the groups, when correctly decoded, will produce the following partial messages:
Group A: ___________________! YOU ___ ___ WINNER. THE ______ IS YOURS!
Group B: ___________________! YOU ARE THE ________. ___ BONUS __ ______!
Group C: ___________________! YOU ___ ___ WINNER. THE ______ IS ______!
Groups D&E: ___________________! YOU ARE THE WINNER. ___ ______ __ ______!
Group F: CONGRATULATIONS! YOU ARE THE WINNER. THE BONUS IS SCAT!
Note that by exchanging data, the collaborator groups can get the entire message, except for the first word, which they would have to guess. The independent group has a longer message, which includes the first word, which none of the other groups have. By working methodically on their own that group can get an entire message, but the last word is incorrect and they can get the bonus only by guessing the correct word. The competitor groups are given the shortest part of the message, but by following their instructions to be aggressive, they may be able to find a way to get the rest of the information. In fact, teachers who have used this exercise report that it is usually one of the competitor groups that wins the bonus.
After one of the groups correctly deciphers the message, the teacher should lead a discussion about the students' reaction to the activity and their thoughts about how the instructions given to the groups compare with what they imagine to be the behavior of real-life scientific researchers. The teacher should help the students identify ethics/values issues that are related to the points the students raise in the discussion.
Some questions that the teacher might ask to stimulate and direct this discussion are
Some suggested questions for this second discussion are
Groups D and E
The Amino Acids
Table 1: The Genetic Code: Codons and the Amino Acids They Code
Table 2 Amino Acid to Character Conversion
RACE FOR THE DOUBLE HELIX -- DATA SHEET
Name ______________________ Group _____ Period _____ Teacher ____________________
substantial investment of classroom time, teachers who have used it with properly prepared students commented that it serves to concretize the mechanism by which DNA codes for protein synthesis, while stimulating very rich and rewarding student discussions of important ethical issues related to the behavior of scientists.
In the discussions, it is important to direct attention to the significance and generality of the issues, rather than the particular circumstances of the student exercise, or the specific personality traits of the characters in the video. These general issues include the common conflict between a scientist's personal values, such as the desire to achieve success or fame, and the ethical demands of the scientific profession. Students should be challenged to consider why collaboration, sharing of information and the fair assignment of credit for discoveries are important to the advancement of scientific knowledge, but may often be compromised due to the fact that scientists are human beings with competing personal needs and desires. An effort should be made to take the discussion arising from the constraints imposed on women in science beyond the obvious negative aspects of overt sexism or racism. A possible way to do this is to ask students to consider whether the ranking of the importance of research problems by women or minority members might be significantly different from the choices made by relatively affluent white males.
For those teachers who can not devote four classroom periods to this lesson, the required time can be cut in half by eliminating either the viewing of the video and related discussion, or the DNA coding exercise. While this significantly reduces the student experience that can be used to probe the issues, teachers report that worthwhile ethic/values education is still achieved.
Return to Part 2 - Model Classroom Lessons
Return to Ethics in the Science Classroom: An Instructional Guide for Secondary School Science Teachers