Activity pubs.acs.org/jchemeduc
Fatty Acid-Containing Lipid Puzzle: A Teaching Tool for Biochemistry Beatrix Büdy* Department of Science and Mathematics, Columbia College Chicago, Chicago, Illinois 60605, United States S Supporting Information *
ABSTRACT: A combination puzzle was developed to assist with the teaching of fatty acidcontaining lipids. The puzzle is a two-sided match-and-flip puzzle; the front side of a puzzle piece bears the names of building blocks, whereas the back of each puzzle piece reveals the corresponding chemical structure. The puzzle promotes intellectual exploration by alleviating the tedious task of memorizing. Finding solutions to the puzzle broadens the understanding of basic concepts such as the structure−function relationship of lipids while highlighting specific molecular details such as functional groups, saturated versus unsaturated fatty acids, and polarity. The strength of the puzzle is its flexibility; it allows the instructor to shift attention from the general building block level to a particular detail of choice without losing focus. The use of the puzzle is intended for nonscience major students and introductory level biochemistry students. Informal feedback from arts-andmedia majors showed that students using the puzzle considered it a helpful and enjoyable aid. KEYWORDS: Second-Year Undergraduate, Biochemistry, Hands-On Learning/Manipulatives, Humor/Puzzles/Games, Fatty Acids, Lipids, Nomenclature/Units/Symbols, Nonmajor Courses
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CONSTRUCTION OF THE PUZZLE The puzzle is a two-sided match-and-flip combination puzzle. It is composed of a key to fatty acid-containing lipids shown in Figure 1 and a set of two-sided puzzle pieces presented in Figure 2. The key uses a building block style approach to classify lipids based on their composition. These categories include triacylglycerols, glycerophospholipids, sphingophospholipids, glycophospholipids, and biological waxes.10 The key also groups these lipids based on their biological functions into the following categories: storage lipids, membrane lipids and protective-coating lipids.11 There are 12 puzzle pieces in the core version of the puzzle. Each piece has two operational sides. The front side displays the name of a building block on a colored background. The back of the piece reveals the corresponding structure on a white background. The structures on the back are partial chemical formulas. Each formula contains one or more incomplete bonds highlighted in red. To generate the structural formula of a lipid, the respective pieces have to be connected at the level of these red bonds. The structural formula of the lipid is chemically correct if all the bonds are connected.
t is an ongoing concern to keep chemistry courses for nonscience majors sufficiently challenging yet interesting. Colleges and universities have started to recognize that the general science requirement for students who do not see themselves as future scientists is often perceived as a boring impediment on the path to graduation.1 To change this perception, engaging science classes are offered to arts and media students.2 Some classes have arts and media related content, whereas other classes have a novel and spirited approach to “hard” science. Innovative teaching methods and interactive teaching tools make these “hard” science classes appealing to the arts and media students. The presented fatty acid-containing lipid puzzle is one such teaching tool used in the biochemistry course. At almost all levels of chemical education, various types of puzzles3−5 proved to turn tedious learning tasks into desirable activities.6−9 The presented puzzle, a two-sided combination puzzle, is used for the teaching of fatty acid-containing lipids. Lipids, in general, are challenging to teach because they do not share a common structural feature. Fatty acid-containing lipids are especially confusing due to their superficial similarity and to the variety of the biological functions. The puzzle, through its modular approach, helps clarify some categories while allowing the students to focus on structure. The puzzle supports the learning objectives of the class: exploration of molecular details within the larger context of biochemistry. Even though the puzzle was developed for a nonscience major class, it has potential use in any introductory biochemistry class by helping to shift attention from the general to the specific without losing focus. © 2012 American Chemical Society and Division of Chemical Education, Inc.
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WORKING WITH THE PUZZLE The puzzle can be used in two main modes: NAME UP and FORMULA UP. Both modes have the same basic instructions: always start with all puzzle pieces facing the same way up (Name or Formula). Select the pieces necessary for your task. Combine them using the Key. Flip them over. Adjust the result if necessary. Read the solution. Published: January 4, 2012 373
dx.doi.org/10.1021/ed200034p | J. Chem. Educ. 2012, 89, 373−375
Journal of Chemical Education
Activity
Figure 1. Key to fatty acid-containing lipids showing the general composition and biological function.
Figure 2. A set of two-sided puzzle pieces.
An example of the NAME UP mode is constructing the formula of a triacylglycerol, an exercise that we often use to introduce storage lipids. First, the students are instructed to place all their puzzle pieces name side up (colored). Then they
are asked to look in their key to find the block diagram for triacylglycerols. Next, they identify and pick the constituent puzzle pieces and use them to reconstruct the diagram. Once they have three green fatty acid residues attached to a purple 374
dx.doi.org/10.1021/ed200034p | J. Chem. Educ. 2012, 89, 373−375
Journal of Chemical Education
Activity
student class evaluations reflected true enthusiasm. Some comments contained references to the experience with the puzzle, including one student’s assertion that “make[ing] sphingolipids understandable and interesting in my mind is [...] special.” Another student said that along with other methods it facilitated the “learning process in a subject that I would otherwise experience great difficulty.” The puzzle was routinely used for the teaching of the basic curriculum. In the class, time was set aside for an informal discussion on special topics. These topics were chosen by the students and they varied from semester to semester. During the past eight semesters that the class was offered, the puzzle was used to illustrate special topics that included storage and mobilization of triacylglycerols; margarine production through catalytic hydrogenation of oils and the formation of “trans” fats; genetic lipid storage disorders involving gangliosides, cerebrosides, and sphingomyelin; and the composition of carnauba wax versus paraffin waxes. The point of discussing the special topics is to give the students a limited but intense experience of being insiders in the world of science. The puzzle is one of many toolkits supporting the general message of the class: the world of science is not an out-of-reach territory. Future fiction writers, filmmakers, dancers, designers, journalists, or poets can understand science if, they are willing to work hard.
glycerol residue, they are asked to flip those pieces over and to join them while paying attention to the red incomplete bonds. At this point, the students should have a correct chemical formula for triacylglycerol constructed from the puzzle pieces. Next, they copy this formula into their notebooks. Considering that the puzzle’s six different fatty acid residues are picked blindly at the beginning, chances are that the students will end up with correct but slightly different formulas. The students work in pairs and then check each other’s formulas, which leads to interesting discussions. Through using the puzzle, the students learn that there is more than one correct solution to the task; they realize that they are working with a class of compounds. The students discover that the constituent fatty acids vary not only by chain length but also by being saturated or unsaturated. It is now the instructor’s role to tell them about fats and oils, to reframe the previously learned cis−trans isomerism, and to explain how trans fats are generated by partial hydrogenation of vegetable oils. Depending on the level of the class, the students can be asked to write a possible hydrogenation reaction, if any, for the triacylglycerol they constructed from the puzzle pieces. An example of the FORMULA FIRST mode is recognizing an unknown formula given by the instructor. This exercise is often used to highlight the structure−function relationship of membrane lipids. The task involves recognizing the formula of a sphingophospholipid. The students reconstruct the unknown formula given by the instructor using the puzzle. Once this task is completed, they flip the structure over to see a block diagram that they identify using the key. The role of the instructor is crucial in transforming the hands-on activity into a genuine learning experience. Now that the formula is familiar to students, the instructor can relate its structure (e.g., “+”, “-“ charges) to lipid bilayers and cell membrane concepts taught during the preceding lecture (e.g., hydrophobic head, hydrophilic tail). The students are encouraged to ask questions. For example, they often ask, “Why do we need that many types of membrane lipids?” This question leads to a deeper one: “How do our cells know how to work together as a whole?” From here the discussion can be steered toward desired topics (e.g., lipids involved in cell signaling). The puzzle can be used alternatively in both modes, NAME UP and FORMULA UP, to aid students in understanding a new lecture, solving problems in class, and completing homework, general reviews, quizzes, or exams. Depending on the curriculum and the teaching strategy of the instructor, a practically inexhaustible number of exercises can be generated by using the puzzle. Once the instructor has introduced the puzzle to the students, they can independently discover additional ways of using it.
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CONCLUSION The puzzle, through its dual approach of general concepts and structural highlights, proved to be a useful aid in teaching fatty acid-containing lipids. It helped the students gain confidence in exploring the world outside their intellectual comfort zone. The puzzle is recommended to introductory biochemistry instructors who are looking for creative ways to engage students.
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ASSOCIATED CONTENT
S Supporting Information *
A downloadable and printable version of the puzzle. For instructors who wish to make their own custom-version, an editable template is also available. This material is available via the Internet at http://pubs.acs.org.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected].
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REFERENCES
(1) Nutman, S. News’ View, Yale Daily News, Jan 22, 2010, http:// www.yaledailynews.com (accessed Nov 2011). (2) Columbia College Chicago is an undergraduate and graduate institution that provides a comprehensive educational opportunity in the arts, communications, and public information within a context of enlightened liberal education. (3) Crute, T. D.; Myers, S. A. J. Chem. Educ. 2007, 89 (3), 373. (4) Follows, D. J. Chem. Educ. 2010, 87 (4), 405−375. (5) Helser, T. L. J. Chem. Educ. 2005, 82 (4), 552. (6) Johnstone, H. J. Chem. Educ. 2010, 87 (1), 22−29. (7) Kelkar, V. D. J. Chem. Educ. 2003, 80 (4), 411. (8) McClure, C. P. J. Chem. Educ. 2009, 86 (10), 1210. (9) Most, C. J. Chem. Educ. 1993, 70 (12), 1039. (10) IUPAC Biochemical Nomenclature, 2nd ed.; Portland Press: London, 1992; pp 180−190. (11) Organic and Biological Chemistry; 4th ed.; Stoker, H. S., White, J., Eds.: Houghton Mifflin, New York, 2007.
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RESULTS Informal student feedback indicates that the puzzle was a helpful and enjoyable aid. The students used it in the classroom and outside the classroom in solving their homework and preparing for exams and quizzes. Written student survey data show that, prior to taking the biochemistry class, the students felt anxious about the class. The survey included comments along the lines of “Science is not my thing.” and “I just want a good/passing grade”. The class, which for many students was their first chemistry class, has an intensive curriculum: organic chemistry basics, carbohydrates, lipids, nucleic acids, proteins, and basics of general metabolism. However, after the completion of the course, written comments on anonymous 375
dx.doi.org/10.1021/ed200034p | J. Chem. Educ. 2012, 89, 373−375
