The Use of Case Studies in an Introductory Biochemistry Course Kathleen Cornely, Providence College Abstract: Case study exercises in an introductory biochemistry course can be used to help students master the content of the course while at the same time help build critical thinking and problem‐solving skills. Case studies can be used in a variety of forms: (1) as in‐class group activities, to either augment or replace content covered in lecture, (2) as homework assignments, completed either individually or in groups, to assess mastery of content and (3) as exam questions, to assess the students’ ability to apply their biochemistry knowledge to a larger context and to discourage rote memorization. Scientific journals as well as articles in the popular press provide rich sources of case study material. A "directed" case study approach allows the instructor to focus student attention on the key content areas that the instructor wishes to cover, doing so in a manner that is interesting and engaging to the students. Introduction:
The case study method has been used extensively in business, law and medical schools, but it was only about 20 years ago that teachers of science caught on to the idea of using case studies in their classrooms. Since then, however, science educators have learned what their law and business counterparts had known all along—that the case study method is an excellent way to teach students the higher‐order analytical and problem‐solving skills they will need to become capable professionals. The case study method, however, is not as widely used as it might be because of the perception that the use of this method would require the instructor to sacrifice course content in order to allow time for the students to work on cases. Contrary to that perception, it is possible to carry out case study analysis without sacrificing content. The “directed” case study method (first described by physiologists Cliff and Wright1) can be used as a vehicle to convey the same content that might otherwise be covered in a lecture format. Directed case study analysis is more focused than an open‐ended case study exercise and involves the introduction of the case by the instructor who then poses a series of specific questions designed to concentrate student attention on certain key issues of the topic. In this manner, the instructor can cover the same scientific content as the lecture, while at the same time, increasing student interest so that concepts are mastered with a greater depth of understanding. “Issues” or “analysis” cases can also be used to convey content. In these types of cases students hone their analytical skills by interpreting graphs and tables and critiquing experimental design in published journal articles. I have used directed case studies in my introductory biochemistry course in several ways: (1) as in‐class group activities, to either augment or replace content covered in lecture, (2) as homework assignments, completed either individually or in groups, to assess mastery of content and (3) as exam questions, to assess the students’ ability to apply their biochemistry knowledge to a larger context and to discourage rote memorization. 1
W. H. Cliff, A. W. Wright (1996) Directed case study method for teaching human anatomy and physiology, Adv. Physiol. Educ. 270, 19–28. Why use case studies? I was fortunate to spend a sabbatical with Harold B. White at the University of Delaware, a co‐founder of the Institute for Transforming Undergraduate Education and a nationally recognized expert in problem‐based learning. We had long conversations about teaching, and whenever I asked him why he did something a certain way, his answer was always the same: “Because it’s constructivism.” Constructivism is the idea that knowledge is constructed in the mind of the learner, by the learner. Social constructivism adds another layer to this concept; the idea of social constructivism is that constructivism is enhanced when learning takes place in a social context. There are many different ways to use active learning techniques that are informed by constructivism; these techniques were recently reviewed in Biochemistry and Molecular Biology Education2. (While the journal’s intended audience is educators of biochemistry and molecular biology, this particular article is an excellent summary of the active learning techniques currently used and is generally applicable to all disciplines.) The authors of the article state that “as the cognitive load increases, the need for social engagement increases”. Biochemistry definitely falls in the category of “high cognitive load”, and when students are engaged in case study analysis in their groups, they are constructing their own knowledge. Knowledge constructed in this way is far likelier to be retained than information delivered by an instructor’s lecture. Homework assignments I have used case studies for homework assignments for nearly 15 years now. When I first began teaching biochemistry I wanted to discourage the students from rote‐memorizing the numerous carbohydrate, protein and lipid metabolic pathways that are de rigeour for any introductory biochemistry course. The approach I used was to design assignments for my students modeled on similar exercises used in medical schools in which medical students are presented with a patient and a list of symptoms and the students are required to diagnose the disease. I decided that the cases I would use would feature patients with an inherited metabolic disease. These patients have an “inborn error of metabolism” in which an enzyme that catalyzes a reaction in a metabolic pathway has been mutated and is no longer functional. While preparing these assignments, I often consulted Stanbury’s classic textbook The Metabolic Basis of Inherited Disease3 Disrupting one reaction in a single cellular pathway has the potential to make a serious impact on other reactions in that metabolic pathway and others. To solve these cases, students were required to use the patient’s symptoms to identify the missing enzyme and to explain why the lack of the enzyme results in the observed symptoms. In some cases, I asked the students to suggest a course of treatment. Mastery of these types of cases of course requires an in‐
depth knowledge of the major cellular metabolic pathways, but using the case as a vehicle to teach the pathways heightened student interest. These clinical cases were a powerful way to demonstrate the interconnectedness of metabolic pathways to the students and to show the students the relevance of biochemistry to the medical field. The students found the cases interesting and relevant, whether or not they were bound for medical school. But since the students needed a good grasp of the metabolic pathways before they were ready to solve these cases, the cases were usually assigned at the end of the 2
Eberlein, T. Kampmeier, J., Minderhout, V., Moog, R., Platt, T., Varma‐Nelson, P., and White, H. B. Biochemistry and Molecular Biology Education 36, pp. 262–273, 2008. 3
Scriver, C. R., Beaudet, A. L., Sly, W. S., and Valle, D, eds. (consulting eds. Stanbury, Wyngaarden and Frederickson) The Metabolic Basis of Inherited Disease, 1989, McGraw‐Hill. semester. My students occasionally asked me, while working on their assignments, “Why don’t we do case studies all semester long?” Why not, indeed? I found the answer to that question as I searched for materials on biochemistry cases that were not related to medicine and found that there were no such resources. Thus I began to write my own cases. I usually use peer‐reviewed journal articles as sources for case study materials. Journal articles contain (to quote Clyde Herreid) “the stuff of science” and the organization of the journal article lends itself to a logical case study format. Turning a journal article into a case produces an “issues” or “analysis” type of case, although I usually approached the case in a directed way. As students solve the case, they are involved in the activity of the discipline. I have amassed a library of about 40 of these case studies that cover the major topics included in an introductory biochemistry course. These cases are available on the WileyPLUS web site as ancillary materials for instructors who have adopted textbooks published by Wiley for use in their courses. I have published a few samples on my own web site. In‐class case studies As I became more comfortable with the idea of using case studies, I began to replace some of my lectures with case study activities. My students form teams, or study groups, at the beginning of the semester and, unless there are difficulties, will stay in the same team for the entire semester. The students work on case studies in their teams during class, and I act as the facilitator. (These same teams work outside of class to complete the case studies assigned as homework, as described above.) These case studies are short “stand alone” activities that fit easily into a single class period and are usually derived from peer‐reviewed published scientific papers. As I circulate throughout the room, posing questions to the students and answering the questions they ask of me, I get a much better sense of how well the students understand the material, which I do not get while I am lecturing. Sometimes misconceptions, learned either in this class or previous classes, come up, which I can address and hopefully dispel. During a case study exercise, the student teams answer the questions posed in the case and, in doing so, learn the difficulty of communicating so that all of the students understand the material. Since each group turns in one copy of the written work at the end of class, it’s essential that the students arrive at consensus when composing and reporting their answers, a process that some teams find challenging. It can be a difficult process, but at the end of the semester, the students show improved verbal and oral communication skills and greater comfort with the complex material. And sometimes it’s difficult to get the students to leave at the end of class; this rarely happens when I am lecturing! I have also found it valuable to have my students work on larger case study projects that I refer to as “content and conflict” cases. These cases combine the elements of the “directed” case as described by Cliff and Wright along with the “decision/dilemma” case described by Herreid.4 In this manner, the students learn important biochemical principles but are also asked to deal with a scientific or social conflict posed in the case. I introduce the element of conflict by dividing the class into groups and giving each group an “interest”. I assign readings based on this interest, and I require the students to assume the point of view of their interest group when solving the case. The student groups make 4
C. F. Herreid (1994) Case studies in science—a novel method of science education, J. Coll. Sci. Teach. 24, 221–229. short presentations to the class, which are followed by questions and a class discussion. Sometimes the class discussions have been quite passionate, as students attempt to support their interest using the information they have obtained in their research of the case. Following the presentations, all of the students are required to write a position paper in which they state their position on the issue, supported with information obtained during the class presentations. I have found these cases to be an invaluable educational tool, but the cases do tend to have a short “shelf‐life”. Students in my current nutritional biochemistry class were interested in the fat substitute Olestra, but the interest isn’t quite as intense now as it was in the mid‐to late 1990s. The anthrax case that I wrote shortly after the terrorist attacks of 2001 has been shelved. On the other hand, my students are still very much interested in a GMO case written by Ann Taylor5 at Wabash College nearly a decade ago. Exams As I began to incorporate more case studies and other group activities into my course, I realized that the traditional manner of assessment no longer seemed applicable. Grades are the currency among the students, and earning top marks is a powerful motivator for upper division students. I realized that if I wanted to communicate to the students that I valued case study analysis, I would need to demonstrate this by having the students solve cases on exams. The cases I use for exams are similar to those used in class, and are based on peer‐reviewed scientific journal articles. I usually post the background material for the exam case about 24 hours prior to the exam, and I’ve learned to be circumspect when writing this material so as to not provide specific search terms for the students that would enable them to locate the original paper. The students are not provided with the questions ahead of time, and are required to complete the exam working individually. I schedule these exams in the evening in order to give the students more time to complete the exam. Source material for case studies A considerable amount of time and effort is required to research and prepare a new case. This is especially true for the case‐study projects. Fortunately, instructors new to the case study method can find case studies published in print and on‐line. The Journal of College Science Teaching, The Journal of Chemical Education and Biochemistry and Molecular Biology Education regularly publish case studies. The National Center for Case Study Teaching in Science has a searchable data base of peer‐reviewed case studies in a wide variety of formats that covers over 75 different specialties and sub‐specialties in science. The Institute for Transforming Undergraduate Education at the University of Delaware has established an on‐line clearinghouse of problem‐based learning activities that can easily be adapted to a case‐study format. 5
Taylor, A., and Sajan, S. (2005) Testing for Genetically Modified Foods Using PCR, J. Chem. Educ., 82, 597‐8.