Abstract:

The co-authors have developed various learning aids for a distance education course in introductory biology. The course is offered via the Internet and includes online laboratory exercises. Although it is not possible to recreate an entire “wet lab” experience, we have developed a combination of video, simulations, virtual microscopy, and game-like exercises that stress concepts and place students in the role of a working biologist. We initially utilized Java applets to simulate laboratory equipment, but are now converting these learning objects to html5 with Java script to enable their use with all computer browsers and on tablets, including Apple iPads. This presentation describes the use of a simulated spectrometer and polyacrylamide gels to enhance student understanding of biological concepts and skills in analyzing data. One spectrophotometer exercise allows students to collect absorption data from several colorimetric enzyme assays. The steps in the assay are first viewed in short videos and students are provided with sets of test tubes from each assay. Students use the simulated spectrophotometer to collect absorption data, then perform calculations to convert absorption to enzyme activity by using a standard curve generated in a previous simulated assay. For assessment, they answer questions related to the effect of time and substrate concentration on enzyme activity. In a similar type of exercise, students use the spectrophotometer to measure absorption in solutions containing spinach chloroplasts and an electron acceptor. The change in absorption over time when the solutions are exposed to different wavelengths of light is measured and used as an indication of photosynthetic activity. The simulated gel is used to illustrate the method of gel electrophoresis as well as differential gene expression in plant organs and during the life cycle of an insect. After watching videos on preparing tissues for electrophoresis, assembling the gel apparatus, and staining a gel, students "run" several simulated gels. In each simulation, they must start the run and watch a tracking dye to determine when to stop the run. Another button stains the gel, and if the bands are well separated (but have not run off the end of the gel) students can answer questions that compare gene expression in begonia flowers vs. leaves and in Drosophila larva, pupa and adult stages. Both the simulated spectrophotometer and gels have been converted to html5/Java script using Adobe Edge Animate as a developer tool. By changing the absorption values associated with numbered "test tubes" within the Edge Animate project, it is possible to use the same spectrophotometer for a variety of different assays as desired by the instructor. Additionally, the Java script changes the absorption values by an instructor-designated amount (currently 1-2%) each time a student uses the simulation. This not only simulates the outcome of actual assays, but deters the copying of data among students in the class. In the simulated gels, an instructor can use the Edge Animate project to change the number and position of bands within each gel. Thus these learning objects are realistic, are easy to customize, and can be used to generate data for a variety of exercises. The simulated spectrophotometer and gels, as well as the exercises in which we use them, may be viewed on our website and are freely available to educators.

Keywords:

Simulation, html5, distance education, online laboratory.