Development of a Semester-Long, Inquiry-Based Laboratory Course

Aug 14, 2014 - A semester-long laboratory course was designed and implemented to familiarize students with modern biochemistry and molecular biology ...
0 downloads 0 Views 2MB Size
Download PDF
Article pubs.acs.org/jchemeduc

Development of a Semester-Long, Inquiry-Based Laboratory Course in Upper-Level Biochemistry and Molecular Biology Pushpalatha P. N. Murthy,*,† Martin Thompson,† and Kedmon Hungwe‡ †

Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States Department of Cognitive and Learning Sciences, Michigan Technological University, Houghton, Michigan 49931, United States

‡

Downloaded via UNIV OF NEW ENGLAND on July 10, 2018 at 17:15:45 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

S Supporting Information *

ABSTRACT: A semester-long laboratory course was designed and implemented to familiarize students with modern biochemistry and molecular biology techniques. The designed format involved active student participation, evaluation of data, and critical thinking, and guided students to become independent researchers. The first part of the course focused on introducing students to common biochemical techniques through a series of open-ended experiments, and the latter part culminated in an original research project. Students defined a problem from a list of suggested projects or one suggested by students, if appropriate. The course was designed to incorporate elements of hypothesis development, project design, teamwork, and communication skills. Each group of students performed experiments under different sets of conditions and all student groups shared results at the end of the lab exercise. A novel aspect of the course was the post-lab presentation and discussion session (PDS) later in the week. During PDS, students presented, interpreted, and discussed their data. In addition, by integrating individual and group results, a more complete picture of the subject was developed by students. The course also encouraged students to combine knowledge gained from previous chemistry courses, and thus, it serves as a capstone course. Formative assessment and instructors’ observations guided changes to the course over three years. Assessment of the course impact using faculty assessment of learning outcomes and student self-report data indicated that the course had met its objectives of improving learning goals, such as hypothesis development, project design, and critical thinking. KEYWORDS: Enzymes, Proteins/Peptides, Nucleic Acids/DNA/RNA, Molecular Biology, Upper-Division Undergraduate, Graduate Education/Research, Biochemistry, Curriculum, Inquiry-Based/Discovery Learning, Problem Solving/Decision Making

■

INTRODUCTION Laboratory instruction plays a critical role in chemical education.1−3 The chemistry laboratory can enhance a fundamental understanding of chemical concepts by providing a medium in which students can interact directly with the material world and bridge the connection between the microscopic and macroscopic realms.3,4 The National Research Council identified a number of important learning goals that can be achieved through laboratory experience, including enhancing mastery of subject matter, developing practical skills, developing scientific reasoning, understanding the complexity and ambiguity of empirical work, cultivating interest in science, developing teamwork abilities, and understanding how scientific research is conducted.3 Clearly, some of these learning goals, such as developing practical skills, understanding the complexity and ambiguity of empirical work, and understanding how scientific research is conducted, can only be achieved through laboratory experiences. Although no single laboratory experiment would achieve all of these goals, lab experiences should be designed to achieve one or more of these goals. A semesterlong laboratory course has been designed and implemented that will familiarize students with modern biochemistry/ © 2014 American Chemical Society and Division of Chemical Education, Inc.

molecular biology techniques in a format that emphasizes reflection and promotes critical thinking and guides students to become independent researchers. Four formats of laboratory instruction are commonly used: expository, guided-inquiry or discovery, problem-based, and inquiry.5,6 These differ in the degree to which instructors structure what students do and the level of student involvement in the design and conduct of the laboratory.5 The expository style describes the traditional instructional method (often referred to as cookbook or recipe-based labs) and the inquiry style is closest to how research is conducted by scientists. While expository experiments are designed to engage students in the lower three cognitive processes, knowledge, comprehension, and application, it places little emphases on thinking, planning, interpreting results, or discussing conclusions.5 The higher cognitive processes, analysis, evaluation, synthesis, and creativity, are not engaged. Guided-inquiry, problem-based, and inquiry-based labs require progressively more student involvement in problem formulating, experimental design, data gathering and data analysis. In the guided-inquiry format, Published: August 14, 2014 1909

dx.doi.org/10.1021/ed400119u | J. Chem. Educ. 2014, 91, 1909−1917

Journal of Chemical Education

Article

Table 1. Experimental Plan for the Biomolecular Chemistry Laboratory

biochemical concepts and techniques. Some of the outcomes reported from these reform initiatives include increased student interest, motivation and active participation,12 and the ability of students to ask more thoughtful questions.17 Nevertheless, there is a paucity of rigorous research data that shed light on the complex process of teaching-learning in a laboratory setting and illuminate the relative advantages and shortcomings of different methods of lab instruction in promoting effective learning.3 The course described herein was designed so that students would have the opportunity to acquire the following learning outcomes: • carry our fundamental biochemical techniques, including the use of biological databases and software • define a problem from a list of projects and design a coherent set of experiments to directly address the problem

students follow a procedure provided by the instructor that tells them what to do and what data to collect, and the instructor then guides them toward developing a general understanding of the underlying concepts through data analysis, evaluation, interpretation, and post-lab discussions.5,6 The National Research Council report Evaluating and Improving Undergraduate Teaching in Science, Technology, Engineering and Mathematics7 emphasizes the need for science education to focus more on developing skills, such as deeper conceptual understanding, critical thinking, and the ability to apply knowledge in novel contexts. Reconsideration of traditional laboratory instruction and a desire to try alternative laboratory teaching formats in which students are required to undertake problem solving has resulted in a number of initiatives in chemistry and biochemistry laboratories.8−17 Some courses have used a single biomolecule, such as a protein11−16 or RNA,17 throughout the course to illustrate 1910

dx.doi.org/10.1021/ed400119u | J. Chem. Educ. 2014, 91, 1909−1917

Journal of Chemical Education

Article

• analyze, evaluate, and interpret data they collect critically, with repetition of experiments if necessary • communicate the work orally in a class discussion setting and in a formal written report using multiple representations (equations, graphs, diagrams, structures) • demonstrate the ability to work effectively in teams To monitor the effectiveness of the course, evaluation was carried out by collecting data from multiple sources. These included (1) faculty assessment of learning outcomes; (2) students’ written self-assessment of the post-lab presentation and discussion sessions (PDS); and (3) student self-assessment of their learning gains using Student Assessment of Learning Gains (SALG). Data from formative assessment were used to improve learning outcomes.

An experimental plan for the course is provided in Table 1. The 3-credit course meets once a week for a 5 h lab session (Tuesday) and once for a 2 h PDS session (Thursday). After the first set of seven experiments (8 weeks), students are familiar with the techniques and ready to undertake a research project in the second part of the course. Weeks 9 and 10 allow teams who have fallen behind to catch up. During the last sixweeks, students define a problem from a list of suggested projects (or one suggested by students, if appropriate), design experiments to address the problem, and carry out the investigation. Four faculty members with research focus in biochemistry/molecular biology have been involved in the original research project component of the course; students are assigned to one of the labs to carry out the research projects. Description of Experiments

■

Fundamental techniques in biochemistry and molecular biology, such as polyacrylamide gel electrophoresis (PAGE), protein extraction and purification, enzyme kinetics, DNA separation and polymerase chain reaction (PCR), are carried out in the first 8 weeks. All work with DNA was approved by the Institutional Biosafety Committee. Experiment 1: Protein Separation. PAGE is generally used to assess protein purity. Simple modifications of the technique can illustrate a number of important aspects of proteins and gel electrophoresis: overall charge, size, shape and subunit composition; the influence of detergents, mercaptoethanol, and acrylamide concentration on sample migration.19 Student groups separate mixtures of proteins of varying subunit composition19 under different conditions, such as denaturing conditions with or without β-mercaptoethanol and varying polyacrylamide concentrations. Photographs of the gel are distributed to all students. In the PDS, student groups presented and interpreted data and deduced the subunit structure and molar mass of proteins provided. This experiment also provided an opportunity to talk about free-radical polymerization. Experiment 2: Enzyme Catalysis, Comparison of Activation Energies of Enzyme-Catalyzed and Noncatalyzed Hydrolysis. Students carry out enzyme-catalyzed and noncatalyzed reactions and calculate the Arrhenius activation energies of both reactions. Student groups carried out the hydrolysis of salicin (salicyl alcohol glucoside) (Scheme 1) by enzymatic (β-glucosidase) and nonenzymatic (acidic) conditions at different temperatures; each group chose different sets of temperatures.20 Progress of the reaction was monitored by assaying the formation of the product, salicylate, spectrophotometrically (A280 nm). Students plotted the data and calculated activation energy (Ea), free energy (ΔG*) and enthalpy (ΔH*) of activation. Stereochemistry of enzyme-

COURSE DETAILS The lab course, Research Methods in Biomolecular Chemistry (CH4721), is required for Biochemistry and Molecular Biology majors and Pharmaceutical Chemistry majors. Students take the course in the second semester of their third year along with Biomolecular Chemistry II. They have been introduced to nucleic acid and protein structure and function in Biomolecular Chemistry I. The course is divided into two distinct phases: instruction in the first 8 weeks focuses on the introduction of common biochemical techniques in a guided-inquiry format. A first goal is that all experiments, including ones that focus on teaching specific techniques, should provide the opportunity to explore biochemistry in an open-ended, guided-inquiry manner. Pre-lab questions prompt students to review relevant material and serve as an introduction for framing questions (Examples: (1) What factors determine the electrophoretic mobility of proteins in polyacrylamide gel electrophoresis? Use equations to explain your answer. (2) What is the structure of mercaptoethanol? What is the role of mercaptoethanol in PAGE? (3) In a PCR mixture, what is the significance of changing the (a) annealing temperature, (b) [Mg2+], (c) template-primer ratio, and (d) elongation time?). Students are paired with different partners (4 or 5 groups of 2 or 3 students per group) for each experiment to develop teamwork skills with different personalities. Instead of all student groups performing the same experiment under identical conditions (expository style), each group performs the experiment under different sets of conditions and records data. Experimental data are shared between groups at the conclusion of the lab exercise. The lab text for the course focuses on the theory and practice of lab techniques, not specific experiments.18 A second goal is to build in opportunities for evaluation of data, interpretation and peer-discussions in a 2 h post-lab PDS later in the week. During this discussion period, student groups present data, explain their results and conclusions, and discuss how their individual data integrates with that of other groups. The goal is to encourage students to think critically and logically about their data and guide them to make relationships between evidence and explanations. This provides an opportunity for discussion and synthesis, and for developing a more complete understanding of the concepts and techniques employed. During the PDS, students are guided to draw knowledge from and make connections to other branches of chemistry, such as organic, physical, and bioanalytical chemistry.

Scheme 1. Hydrolysis of Salicin

1911

dx.doi.org/10.1021/ed400119u | J. Chem. Educ. 2014, 91, 1909−1917

Journal of Chemical Education

Article

Teaching Assistants and PDS discussion, one set of studentdesigned primers was ordered for each group. Experiment 7: PCR Reaction and Separation of DNA Products. Students carried out PCR amplification of target cDNA (PPO or alkaline phytase) using primers they had designed. They varied annealing temperatures, magnesium ion concentrations, and template-primer ratios to clarify PCR concepts; groups varied one or two parameters of their choosing. Agarose gel electrophoresis was performed to assess the results of PCR experiments. Migration distances of DNA fragments were compared to a standard DNA ladder to estimate fragment length. Photographs of the gel were recorded and distributed to all students for analysis and group discussion. Experiment 8: Cleavage of Plasmid with Restriction Endonucleases and Separation of DNA Products. Students carry out restriction endonuclease reactions on plasmids (pET, pMAL, or pPICZ) using one or more endonucleases and construct restriction maps. Different student groups used different plasmids and endonucleases, and compared their results after separation by agarose gel electrophoresis. Photographs of the gel were recorded and distributed to all students for analysis and group discussion. Experiment 9: Original Research Projects. After exposure to a number of techniques in the first portion of the course, students had the necessary background to undertake an original research project to answer student-generated questions. The independent research portion of the lab challenged students to pose questions, design experimental protocol, gather and analyze data, and finally, interpret and draw conclusions. The following points guided this portion of the course: • The projects are in areas where the instructors are highly knowledgeable namely, areas of their research interests. This ensured that the chemicals, instruments, and safety requirements of the project were readily met. Students were presented with a topic and asked to investigate an aspect of the problem. A few pertinent literature references were provided. Students were required to pose a question and submit an experimental procedure that, when successfully completed, would provide experimental data to answer the question posed. Following approval of the procedure by the instructor, students performed the experiment and submitted a written report. • The projects were narrowly defined so that there were a limited number of obvious paths for students to take. If the possibilities were too large, students could become confused or frustrated.14 • Projects were clearly related to and built on earlier experiments. Projects were of four-week duration. A number of projects in areas of instructor interest and expertise were presented to students. Examples of projects carried out by students include the following: (1) thermal stability of lysozyme in trehalose solution at acidic and basic pH; (2) optimization of cell lysis to release alkaline phytase from Pichia pastoris: effect of mercaptoethanol and silica/ zirconium beads; (3) cloning and expression of bromodomain variants; (4) determination of copy number of foreign gene in transformed clones of P. pastoris by qPCR; (5) effect of sodium sulfate on the thermal stability of lysozyme; (6) the cloning of Mus musculus polybromo1 in pET30B vector; (7) interaction of

catalyzed (retention of stereochemistry) and acid-catalyzed (racemization) reactions was discussed in PDS. Experiments 3 and 4: Enzyme Extraction and Purification. To clarify concepts employed in protein purification, kinetics and inhibition, an enzyme catalyzing an everyday process (“real world” application) that students are familiar with is chosen. Browning of fruits and vegetables is caused by the oxidation of benzenediols to quinones by polyphenol oxidase (PPO; also called tyrosinase or catechol oxidase) and subsequent polymerization to brown, red or black pigments.21,22 Fruits and vegetables provide a ready inexpensive source of enzyme, the enzyme assay is quick and dependable, and the enzyme is stable.22,23 Students extract and partially purify PPO from a fruit or vegetables of their choosing (potato, banana, mushroom, apples, avocado, eggplant, etc.) and compare Km and Vmax. The enzyme was assayed spectrophotometrically by monitoring the conversion of catechol to quinone (A420 nm) (Scheme 2).23,24 Purification techniques included Scheme 2. Polyphenol Oxidase-Catalyzed Oxidation of Catechol

ammonium sulfate precipitation at different concentrations, dialysis, and PAGE. Student groups tried precipitation at different ammonium sulfate concentrations and compared results. Enzyme assays and SDS-PAGE were employed to monitor protein purification. Experiment 5: Kinetic and Inhibition Studies. Inhibition of browning is very important to the food processing industry since browning negatively affects the appearance, texture, and taste. All groups worked with PPO from banana to determine Km and Vmax values. A number of inhibitors (2,3diaminopropanioc acid, sodium azide, EDTA, p-nitrophenol, etc.) which differed in the type of inhibition (competitive, noncompetitive, etc.) were investigated. Groups were assigned different inhibitors and the data were compared.21,23 Experiments 6−8: Enzymatic Manipulation of DNA Molecules. Polymerase chain reaction (PCR) amplification and cleavage of DNA molecules using site-specific restriction endonucleases are common techniques to enzymatically manipulate DNA. Students were introduced to DNA by performing PCR reactions, endonuclease cleavage of DNA, and separation of DNA products. Experiment 6: Introduction to Biological Databases Primer Design. Students located the gene sequence corresponding to PPO (from numerous sources) using the National Center for Biotechnology Information (NCBI) Web site and conducted sequence analysis (BLAST), sequence alignment (Clustal W), phylogenetic (Phylip) and other analysis using NCBI or Biology Workbench (San Diego Supercomputer Center). Students designed primers to amplify PPO (from Trifolium pratense, red clover) cDNA or alkaline phytase (from Lillium longiflorum, Ester lily) cDNA. They varied length, base composition and annealing temperatures and used computer algorithms (Integrated DNA technologies; idtdna.com) to evaluate primers (Tm, primer dimer or adverse secondary structure formation). After consultation with 1912

dx.doi.org/10.1021/ed400119u | J. Chem. Educ. 2014, 91, 1909−1917

Journal of Chemical Education

Article

lectins with carbohydrate cancer antigen; (8) screening of lectins to recognize human blood group antigens.

Table 2. Faculty Assessment of Final Research Projects

Grading

Assessment Criteria

Students were graded on pre-lab exercises, lab participation, and lab reports. Students submitted seven small (3−5 pages) lab reports (abstract, introduction, methods, results, discussion, references) and one large lab (5−7 pages) report (abstract, introduction, materials and methods, results, discussion, references) for the research project. In an effort to encourage students to participate without the pressure of faculty evaluation, PDS were not graded.

Use of fundamental biochemical techniques to address the problem

ASSESSMENT OF COURSE IMPACT The assessment data for the project came from three sources: (1) faculty assessment of learning outcomes; (2) students’ written self-assessment of the PDS; and (3) student selfassessment of their learning gains using SALG. Approval was obtained from the Institutional Human Subjects Committee for this project. The data presented are from three cohorts: Cohort 1 of 7 students, Cohort 2 of 7 students, and Cohort 3 of 14 students. The numbers of students, although small, are not unusual for an upper-division lab course in a specialized area. Numbers are expected to grow as the course is now required for Biochemistry and Molecular Biology majors.

Clarity and adequacy of data presentation

Clarity and coherence of rationale for experimental design Analyze data, repeat experiments if necessary, and discuss conclusions

■

Use of representations (equations, graphs, diagrams, structures)

Instructor Ratings (n = 10)a Mean 4.8 Mode 5 Range 1 Mean 4.8 Mode 5 Range 1 Mean 4.4 Mode 5 Range 3 Mean 4.7 Mode 5 Range 2 Mean 4.7 Mode 5 Range 1

a

The projects were assessed using a 5-point scale: 1 = poor; 2 = fair; 3 = adequate; 4 = good; 5 = very good.

(3) Did your understanding change as a result of the discussion? (4) Based on your experiences, do you have any suggestions for how to improve the PDS? To encourage students to provide candid comments, instructors left the room when the external observer was receiving the written feedback. De-identified data summaries were shared and discussed with the instructional team to aid them in reviewing and refining the course. The following is a sample of responses from Cohorts 1 and 2. The responses were selected to reflect the range of views. In response to Question 1, the responses included the following: • “To better understand concepts and realize real world experiment [sic]. To improve skills of explanation of theory on real life. To prepare for further study.” • “To accurately present data and provide an interpretation of the results.” • “To answer questions successfully.” • “To communicate our results in a clear and concise manner and answer questions.” • “My goal was to strengthen my theoretical knowledge about techniques, by doing the experiment followed by discussion.” • “Mostly correct mistakes I made when interpreting the lab results. Also to answer questions I had about the lab. To explain the data based on previous knowledge and the limited information about what material were used.” The student responses indicated some focus on conceptual understanding through their use of words such as “explaining”, “understanding”, and “interpreting”. Moreover, the words explaining and interpreting are indicators of relatively highlevel cognitive goals.25 Another type of response pointed to some preoccupation with performance rather than learning (e.g., “[my goal was] answering questions”). Student responses to Question 2, were positive, even when it meant that they had to review and rethink their results and interpretations. Among the comments were the following: • “The discussions, while nerve wrecking in the beginning, helped immensely to think through data.”

Faculty Assessment of Learning Outcomes

• The final research project encompassed all the stated learning goals: Students defined a problem from a list of projects. • Teams had to design a coherent set of experiments employing fundamental biochemical techniques they had learned, to address the problem. • Teamwork skills cultivated throughout the semester were required to complete the project. Individuals in the group were required to coordinate solution preparation, equipment availability and readiness, and data gathering duties. • Teams had to analyze data, repeat experiments if necessary, and discuss conclusions. Teams had to communicate their work in an oral presentation that involved class discussion and a written report evaluated by the instructor(s). Ten group projects were assessed, three from Cohort 2 and seven from Cohort 3. The written report for the final research project was assessed on the basis of five criteria that were aligned with the goals of the course. The instructor ratings are summarized in Table 2. The mean instructor ratings were high. The ranges were small, except in analysis of data and interpretation where the range was 3. In this particular case, the mode and the mean were in the high range. Taken as a whole, the data indicate strong student performances on the final project and suggest that the learning goals of the course were met. Students’ Written Self-Assessment of PDS

An external observer (K.H.) observed student presentations and asked students to provide written comments to open ended prompt questions: (1) What were your goals for today’s presentation? (2) Do you think you achieved the goals for the presentation? 1913

dx.doi.org/10.1021/ed400119u | J. Chem. Educ. 2014, 91, 1909−1917

Journal of Chemical Education

Article

• “Yes, a lot of the fundamentals about the process became instilled when logical explanation was obtained in the discussion. It is easier to forget what you study, but once we do, we know the details.” • “Yes, [but] they never give us the information we needed to interpret the results until discussion.” • “Yes, we discussed possible reasons for the results with input from the students and the instructors. It was a group effort to grasp the topic.” • “The discussions process requires us to look over more information about concepts.” “Definitely more questions I had coming in were answered so my understanding definitely improved.” • “Yes, my understanding was changed specifically about a concept used in the experiment. The concept was made clearer to me.” • “Yes, some. It is still not entirely clear how the professor drew some of the conclusions. They make sense, but getting there seems like magic.” In all cases, students’ response to Question 3 indicated improved understandings. However, they found that as they learned, more questions arose. The following are examples:

End-of-Semester Student Self-Assessment of Their Learning Gains Using SALG

The results of a SALG survey provide a perspective on student learning.26 The instrument is based on the assumption that students can make realistic appraisals of their learning gains and the quality of instructional arrangements and support. During the period of introduction and experimentation of the guided inquiry (GI) project (CH4721), an equivalent laboratory course, which followed a traditional learning (TL) format, was offered in the Department of Biological Sciences (BL4820, Biochemical Laboratory techniques). In BL4820, students were given detailed instructions for the experiment and assisted in the laboratory. After the lab session, students were required to sort through the data and turn in a written lab report, which was then graded. The two courses were equivalent in terms of the concepts covered and students were free to choose between the two options. Responses of the GI groups to SALG were compared with those from the TL course. The original SALG instrument,26 which contained a total of 51 questions, was modified to assess the goals of the course better; seven questions that were not relevant to the learning outcomes were deleted and two questions that focused on process skills were added to make a total of 46 items (see Supporting Information). Of these, 29 questions focused on content knowledge and process skills. The core process skills, as drawn from the literature, include observation, communication, measurement, inference, and prediction.27 The reliability of the SALG scale was assessed by running the Cronbach α procedure on the statistical package Statistical Package for the Social Sciences, SPSS. The Cronbach α is a measure of internal consistency, that is, how closely related a set of items are as a group. The theoretical value of α varies from zero to 1. The Cronbach α value for the scale was 0.972, a high value.28 Effect size (Cohen’s d) has been used as the statistical measure of the impact of the intervention.29 The effect size is the standardized mean difference between the two groups. When two means are compared, d is defined as the difference between two means divided by the pooled standard deviation for the means.29 The pooled standard deviation is defined as eq 1:

• “The more I deepen my understanding, the more questions arise.” • “The discussion just offers basic structure for further study.” • “I know more about some aspects. But my knowledge of other aspects was not deepened.” The following are examples of their suggestions to the Question 4: • “No changes, I like the interactive approach.” • “It would be nice to have all the data one would normally have access to when running an experiment. Essentially, give more rather than less information about the materials and all will be well.” • “I often feel that [we] students do not know what background knowledge is needed for the presentation.” When asked to make additional open-ended comments about their experiences, the student responses indicated that they were not accustomed to presenting findings to an audience, justifying their results, and dealing with ambiguities where there was no clear right answer. They all agreed the course was different from previous courses they had taken. Among their comments were the following: • “Other course are focused on how well you follow directions rather than analysis of data and presentation of results” • “I have never had classes with experiments being conducted where I did not know or had an idea about the results • “The discussions were completely unique to the class. I have never before been asked to think in-depth about the analysis of experimental results.” Their experiences can be summarized by the comments of a graduating student who described the course as the most realistic she had taken about how to conduct research and how to write for a professional audience.

SDpooled =

SD12 + SD22 2

(1)

where SD1 and SD2 are the standard deviations of sample 1 and sample 2, respectively.29 The most commonly used interpretation of Cohen’s d is that values below 0.2 are indicative of a small effect, 0.5 a medium effect, and 0.8 and above indicates a large effect.29 The comparison data for the TL and GI groups are summarized in Table 3. SALG data were obtained from students in Cohort 1 and 2. A total of 25 students from the TL group formed the comparison group. Table 3. Summary of Student Self-Assessment on the SALG

Comparison Full scale Subscale: content knowledge and process skills 1914

GI (Guided Inquiry) n = 14

TL (Traditional Learning) n = 25

Mean 3.87 SD 0.52 Mean 3.95 SD 0.55

Mean 3.75 SD 0.71 Mean 3.72 SD 0.82

Effect Size, d 0. 18 0.33

dx.doi.org/10.1021/ed400119u | J. Chem. Educ. 2014, 91, 1909−1917

Journal of Chemical Education

Article

questions so that each student group fielded questions from one faculty member not multiple faculty. Students did find this format intimidating at first, but relaxed as the semester progressed. The fact that PDSs were not graded also helped ease the stress. The experiments and grading of lab reports were divided between two instructors (PPM and MT). Students noted that the grading of lab reports between the two instructors was not consistent. To enhance consistency, graded lab reports were exchanged between instructors, and the grading rubric was discussed among instructors and with students. This resolved grading disparities and kept students informed of the grading rubric. Four faculty members were involved in the original research project phase of the course. Students noted that expectations (time spent on research and progress expected) varied between faculty members. The faculty involved discussed and clarified learning goals so that expectations were more uniform in subsequent years. Students had trouble getting good data (close replicate values) from protein experiments 1−5 (Table 1). This may be because the protein experiments were more sensitive to poor pipetting techniques and inexperience working with multiple (8 to 20) test tubes in the early part of the course. The order of the experiments was changed: the DNA experiments (6 and 7) were conducted first followed by the protein experiments. Additionally, whenever possible, students in groups carried out the experiments individually so that there are two sets of data for each experimental condition.

The effect size on the full SALG scale was 0.18 which is a small effect based on Cohen’s criteria. An effect size analysis was also conducted on the combined content knowledge and process skills subscale because they were the primary target of the project. The effect size for the subscale was 0.33, which is within the medium effect range. The effect size indicated that the intervention was successful in meeting the goals of the course; this score is in line with other studies.30,31 A larger sample would have improved the reliability of the measurements. The data should be interpreted in conjunction with findings from faculty assessment of projects, and student selfassessment of the PDS sessions. In summary, the data presented have been drawn from several perspectives. When assessed as a whole, the findings indicated that the project achieved its goal of designing a course that achieved the stated learning outcomes: pose questions, design experiments, evaluate and interpret data, and communicate results.

■

OBSERVATIONS AND ADJUSTMENTS ON THE COURSE Students were extremely uncomfortable with the open-ended nature of experiments, they wanted the “right answer.” They had a difficult time interpreting data that did not lead to unambiguous conclusions. A goal of the course was for students to feel the discomfort of ambiguous empirical data, but not to be overwhelmed by it. In an effort to address these issues, the learning goals for the course were articulated to students a number of times during the semester. Students were made aware that the experiments are open-ended inquiry exercises so the answers are not known, even to the instructors; experiments were designed to stretch skills, such as critical thinking, data analysis and interpretation; students will be pushed beyond their comfort zone and may feel “uncomfortable”. Instructors found the PDS to be very useful. This allowed instructors to engage students in data evaluation and interpretation, and guide them to draw conclusions. The post-lab sessions were conducted before students turned in lab reports, so the lab reports incorporated points discussed during PDS and were of better quality. Students needed significant help with both oral communication (what and how to present data and then deduce what the data implied) and report writing even though students were advanced undergraduates (final year, 85%) and graduate students (15%). A lecture on writing lab reports was introduced in response to student requests. The additional lecture significantly improved the quality of reports. In addition, students were required to write individual lab reports rather than a group report to ensure that all students acquired report writing skills. Graduate teaching assistants in the laboratory oversaw student groups doing slightly different experiments, and encountered different problems. Therefore, they needed to be more experienced and able to handle the wide variety of questions that arose. Learning to manage the PDS in an open, constructive environment so that students are challenged, but not intimidated, has been a learning process for instructors. The first group to present faced most of the questions, so subsequent groups benefitted from going later. To address this, the group that went first was rotated and PDSs were not graded. In addition, faculty members took turns asking

■

SUMMARY The semester-long biochemistry and molecular biology laboratory course was designed to facilitate more active student participation in data analysis, interpretation and evaluation, and to incorporate elements of hypothesis development, project design, team work, critical inquiry, and communication skills. Novel aspects of the course included a PDS during which students presented and interpreted data, discussed results, and integrated their results with that from other groups to develop a more complete picture of the subject. The experiments and presentations clearly pushed students to the limits of their understanding. There is evidence that, to some degree, students found this form of learning uncomfortable. This is consistent with the literature that indicates that students tend to find changes to instruction that increase their responsibility for learning uncomfortable.32,33 The challenge for the instructors was always to find the right balance between independent student work and instructional support. Research in the learning sciences states that the right balance is struck within the zone of proximal development (ZPD). Vygotsky34 defined the ZPD as the instructional space on the borders of student capacity, where the tasks are not so easy that students can do them on their own, nor are they so difficult that they are not able to learn productively. The evidence that the instruction was within the ZPD is twofold. First, students’ self-report statements indicated that the experiments and associated presentations went beyond their prior experiences in traditional lab courses. They were challenged to think in new ways, and clearly experienced some discomfort. Second, all students surveyed reported growth in understanding, even as new questions arose in their minds. The effect size on the comparison of SALG scores for TL and GI groups, although modest, indicated a gain in learning gains, supporting other self1915

dx.doi.org/10.1021/ed400119u | J. Chem. Educ. 2014, 91, 1909−1917

Journal of Chemical Education

Article

(11) Merritt, M. V.; Schneider, M. J.; Darlington, J. A. Experimental Design in The General Chemistry Laboratory. J. Chem. Educ. 1993, 70 (8), 660−662. (12) Wolfson, A. J.; Hall, M. L.; Branham, T. R. An Integrated Biochemistry Laboratory, Including Molecular Modeling. J. Chem. Educ. 1996, 73 (11), 1026−1029. (13) Brockman, M.; Ordman, A. B.; Campbell, A. M. Research in Undergraduate Instruction: A Biotech Lab Project for Recombinant DNA Protein Expression in Bacteria. J. Chem. Educ. 1996, 73 (6), 542−543. (14) Craig, P. A. A Project-Oriented Biochemistry Laboratory Course. J. Chem. Educ. 1999, 76 (8), 1130−1136. (15) Vincent, J. B.; Woski, S. A. Cytochrome c: A Biochemistry Laboratory Course. J. Chem. Educ. 2005, 82 (8), 1211−1214. (16) Kirk, S. R.; Silverstein, T. P.; McFarlane Holman, K. L.; Taylor, B. L. H. Probing Changes in the Conformation of tRNAPhe: An Integrated Biochemistry Laboratory Course. J. Chem. Educ. 2008, 85 (5), 666−673. (17) Hofstein, A.; Navon, O.; Kipnis, M.; Mamlok-Naaman, R. Developing Students’ Ability to Ask More and Better Questions Resulting from Inquiry-Type Chemistry Laboratories. J. Res. Sci. Teach. 2005, 42 (7), 791−806. (18) Pingoud, A.; Urbanke, C.; Hoggett, J.; Jeltsch, A. Biochemical Methods: A Concise Guide for Students and Researchers, 1st ed.; WileyVCH: Weinheim, 2002. (19) Powers, J. L.; Andrews, C. S.; St Antoine, C. C.; Jain, S. S.; Bevilacqua, V. L. H. An SDS-PAGE Examination of Protein Quaternary Structure and Disulfide Bonding for a Biochemistry Laboratory. J. Chem. Educ. 2005, 82 (1), 93−95. (20) Adams, K. R.; Meyers, M. B. Activation Energies for An Enzyme-Catalyzed and Acid Catalyzed Hydrolysis: An Introductory Interdisciplinary Experiment for Chemists and Biochemists. J. Chem. Educ. 1985, 62 (1), 86−88. (21) Mayer, A. M. Polyphenol Oxidases in Plants and Fungi: Going Places? A Review. Phytochemistry 2006, 67 (21), 2318−2331. (22) Sanchez-Ferrer, A.; Rodriguez-Lopez, J. N.; Garcia-Canovas, F.; Garcia-Carmona, F. Tyrosinase: A Comprehensive Review of Its Mechanism. Biochim. Biophys. Acta 1995, 1247 (1), 1−11. (23) Arslan, O.; Dogan, S. Inhibition of Polyphenol Oxidase Obtained from Various Sources by 2,3-Diaminopropionic Acid. J. Sci. Food Agr. 2005, 85 (9), 1499−1504. (24) Lim, K. F. Inhibition of the Reaction Kinetics of the Enzyme ODiphenol Oxidase: An APCELL Experiment. Aust. JEC 2002, 59 (issue), 11−16. http://www.raci.org.au/divisions/chemical-educationdivision (accessed September 2007). (25) Bloom, B. S. Taxonomy of Educational Objectives, Handbook I: The Cognitive Domain; David McKay Co., Inc.: New York, 1956. (26) Seymour, E.; Wiese, D.; Hunter, A.; Daffinrud, S. M. Creating a Better Mousetrap: On-line Student Assessment of their Learning Gains. Paper presented at the National Meeting of the American Chemical Society, San Francisco, CA, March 2000. http://www. salgsite.org/docs/SALGPaperPresentationAtACS.pdf (accessed September 2012). (27) National Research Council. National Science Education Standards; National Academies Press: Washington, DC, 1996. (28) Tanner, D. Using Statistics To Make Educational Decisions; Sage Publishers: Los Angeles, CA, 2012; pp 398−400. (29) Cohen, J. Statistical Power Analysis for the Behavioral Sciences, 2nd ed.; Lawrence Earlbaum Associates: Hillsdale, NJ, 1988; pp 20− 27. (30) Durlak, J. A. How To Select, Calculate, and Interpret Effect Sizes. Pediatr. Psychol. 2009, 34 (9), 917−928. (31) Shymansky, J.; Hedges, L.; Woodworth, G. A Reassessment of the Effects of Inquiry-Based Science Curricula of the 60’s on Student Performance. J. Res. Sci. Teach. 1990, 27 (2), 127−144. (32) Brickman, P.; Gormally, C.; Armstrong, N.; Hallar, B. Effects of Inquiry-Based Learning on Students’ Science Literacy Skills and Confidence. IJ-SoTL 2009, 3 (2), 1−22.

reported student data. When these were combined with instructors’ assessment of student projects, the overall results from the project indicated a course that met the desired learning outcomes: hypothesis development, project design, critical thinking, and communication. This course has now been adopted as a regular course offering.

■

ASSOCIATED CONTENT

S Supporting Information *

Student handouts for each of the experiments and SALG questions and raw data. This material is available via the Internet at http://pubs.acs.org.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Notes

This material is based upon work supported by (while serving at) the National Science Foundation. Any opinion, findings, and conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS The authors thank the National Science Foundation (DUE 0827220) for partial finding of this project and MTU for generous funding support. We thank the graduate teaching assistants (Steven Johnson, Mimi Yang and Sasha Teymorian) who helped in the development and subsequent revisions of the course, and the undergraduate students who took the course during the initial offering and provided invaluable feedback.

■

REFERENCES

(1) Elliott, M. J.; Stewart, K. K.; Lagowski, J. J. The Role of the Laboratory in Chemistry Instruction. J. Chem. Educ. 2008, 85 (1), 145−149. (2) Moore, J. W. Let’s Go for an A in Lab. J. Chem. Educ. 2006, 83 (4), 519. (3) America’s Lab Report: Investigations in High School Science; Singer, S. R., Hilton, M. L., Schweingruber, H. A., Eds.; National Research Council: Washington DC, 2005. (4) Buntine, M. A.; Read, J. R.; Barrie, S. C.; Bucat, R. B.; Crisp, G. T.; George, A. V.; Jamie, I. M.; Kable, S. H. Advancing Chemistry by Enhancing Learning in the Laboratory (ACELL): A Model for Providing Professional and Personal Development and Facilitating Improved Student Laboratory Learning Outcomes. Chem. Educ. Res. Pract. 2007, 8 (2), 232−254. (5) Domin, D. S. A Review of Laboratory Instruction Styles. J. Chem. Educ. 1999, 76 (4), 543−547. (6) Domin, D. S. Students’ Perceptions of When Conceptual Development Occurs During Laboratory Instruction. Chem. Educ. Res. Pract. 2007, 8 (2), 140−152. (7) Evaluating and Improving Undergraduate Teaching in Science, Technology, Engineering and Mathematics; Fox, M. A., Hackerman, N., Eds.; National Research Council: Washington DC, 2003. (8) Dreisbach, J. H. A Problems-Oriented Biochemistry Laboratory Program. J. Chem. Educ. 1986, 63 (12), 1068−1069. (9) Ricci, R. W.; Ditzler, M. A. Discovery Chemistry: A LaboratoryCentered Approach to Teaching General Chemistry. J. Chem. Educ. 1991, 68 (3), 228−231. (10) Markwell, J. Focusing on A Single Enzyme: An Undergraduate Biochemistry Laboratory Course Supported by The NSF. J. Chem. Educ. 1993, 70 (12), 1018−1019. 1916

dx.doi.org/10.1021/ed400119u | J. Chem. Educ. 2014, 91, 1909−1917

Journal of Chemical Education

Article

(33) Wenning, C. J. SAAMEE: A Model for Academic Success. J. Phys. Teach. Educ. Online 2005, 3 (2), 29−33. (34) Vygotsky, L. Mind in Society: The Development of Higher Psychological Processes; Harvard University Press: Cambridge, MA, 1978; pp 32−35.

1917

dx.doi.org/10.1021/ed400119u | J. Chem. Educ. 2014, 91, 1909−1917