the computer
Editor's Note In addition to Eureka, two other generalpurpose equation-solving software packages are of potential interest to chemical educators: MathCAD and T K Solver Plus. For further information about Eureka, contact Borland International, 4585 Scotts Valley Drive, Scotts Valley, CA95066; about MathCAD, contact Mathsoft, Inc., One Kendall Square, Cambridge, MA 02139; and about TK Solver Plus, contact Technical Systems, 1220 Rock Street, Rockford, IL 61101. Several reviews of these equation solvers have appeared recently: 1. Stewart. G. A. BYTE 1988, 13(2), 168: BYTE 1987,
Stereo Helix Stereo view of abha helix structure
Making Stereo Pair Views with Molecular Editor
"Move" menu, and choose "Rotate". The right hand view will rotate enough so that when the pair is viewed either with a stereo viewer or by defocusing the eyes, it will give the illusion of a single.. three-dimensional model in the center of the screen. Of course, it may also be printed out for observation away from the computer. ~~~~
Trevor Roblnson Department of Biochemistry University ol Massachusells Amharst, MA 01003 The program Molecular Editor for Macintosh computers (available from Kinko's Academic Courseware Exchange, 255 West Stanley Ave., Ventura, CA 93001) is an easy to use and inexpensive program for building, rotating, and observing molecular structures in three dimensions. I t has an additional capability not mentioned in the aecompanying documentation. Any molecule that has been constructed can very easily be converted into a stereo pair view so that its three-dimensional nature becomes even more vivid than when "rotated" on a flat srreen. The following step-by-step procedure for making stereo paira has been used by one of my classes and seems to he foolproof. The figure shows a stereo view of the alpha helix of protein structure, which was produced by this method. The model to he converted to a stereo view must he small enoueh to fit on half of the screen. If too big, it can he reduced by using the"Srale Model" function. Selert the model using marquee or the "Select All" rommand under "Edit" menu. Move it to fit into the left half of the screen hy holding down the 'Option" key, then position the cursor arrow on any atom in the model, and move it to position. While it is still selected. choose"Copyn under the"EditV menu,rlick the mouse button, and then rhoosc "l'aste". This will "paste" a copy of the model directIg on top of the original. Now, while it is still selected, hold dew "Option" and "Shift". position the cursor arrow on any atom, and move the "top" copy to the right so that the space between corresponding atoms in the two copies is about 6 em. Select the right hand copy. Choose "Rotation Settings" uuder the "Move" menu. Set a t 5' around the Y-axis, and "Single Step". Go hack to the
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Journal of Chemical Education
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Generating Individualized Exam Questions Bruce N. Campbell, Jr. SUNY Potsdam PODdam, New York 13676 Much concern has been focused recently on making easier the use of computers in teaching. Software must match what is already done in the course, or the instructor must modify the program, modify the organization of the course, or write the software to he used. These tasks may well he sufficiently onerous that the whole activity is avoided. Another approach would be to employ "generic" software, intended to he easily modified by the user. Commonly available examples are software packages that allow the integrated use of database, spreadsheet, and word-processing activities. This note reports a simple use of such software to generate individualized take-home examination questions. I t has been my practice to include a question in one of my biochemistry examinations h that requlres the student to ~ a p enzyme kinetir data, calculate from thegraph values ior V,.. and K v (with and without inhibitor), and draw appropriate conclusions. Even with due warning, the actual graphing in class monopolizes the time of most students. The answer appeared to he to give the graphing question as a take-home part of the exam, using Appleworks to create a different problem for each student. Each prohlem consisted of two parts: the directions and a tahle of data. The directions were stored as a word-processor file. The unique tahle of data was generated from a spreadsheet file.
The spreadsheet file was established with values for V,,, and KIA (with and without inhibitor), m n number, concentration of substrate and effector compounds and columns for kinetic values to oermit olottine t h e d a t a by the %lich&lis-M'entol I.ineweaver-Rurke, or Hancs equations. Elsewhere on thespreadsheet an answer key was generated by recording the values of V,-,, and KM as each run was performed. The cells for the kinetic values were established as formulas based on the values for V-, KM,and [S] that had been supplied. The calculation was done in the manual mode. The file was saved and then the run numher and the kinetic data, complete with headings, were transferred to an intermediate memory (clipboard) with a copy as a hlock command. The question text in the word processor could then be called and the data hlock added to it hefore printing. The process could he repeated with new values inserted into the ooerator cells for the next run. The storage area (answer key) was con. sulted to he sure there was no duplication of values coupled with type of inhil~ition.It is also important to know the range of values that will give useful graphs with the [S] values used. After the last problem has been printed, the answer key can he printed also. This approach could he used for problem requiring analysis of large amounts of data and emphasizes the possibility of using available generic software with facile user modification to fit specific course situations.
Enhanclng Physical Chemistry Lectures with Overhead Monitors Davld M. Whisnant Woffwd College Sparfanburg. SC 29301
The uses of microcomputers to enhance lecture presentations has been described1,
