Textbook illustrations of 3D biopolymers on printed paper, regardless of how detailed and colorful, suffer from its two-dimensionality. For beginners, computer screen display of skeletal models of biopolymers and their animation usually does not provide the at-a-glance 3D perception and details, which can be done by good hand-held models. Here, we report a study on how our students learned more from using our ordered DNA and protein models assembled from colored computer-printouts on transparency film sheets that have useful structural details. Our models (reported in BAMBED 2009), having certain distinguished features, helped our students to grasp various aspects of these biopolymers that they usually find difficult. Quantitative and qualitative learning data from this study are reported.Keywords: Helical structure, DNA, polypeptide, science education.Helical structures of biopolymers are ordered and have symmetry in three dimensions. College students have to learn about helices of the double-stranded DNA, the single-stranded protein a-helix, and possibly others in bioscience classes. Even high school students studying biology are exposed to these common helical structures and are examined for their knowledge of these structures. However, when asked to draw a sketch of the DNA double helix with as little details as that drawn by Francis Crick's wife, Odile, for the seminal Nature paper in 1953 [1], quite a few students, including some graduates, cannot do it well: no clear helical (right-handed) sense, haphazard hydrogen bondings between basepairs, no major and minor grooves, the strands are not antiparallel, and so forth. Students do not perform much better with the bare-backbone polypeptide a-helix: no clear helical (right-handed) sense, haphazard hydrogen bondings, each amino acid residue is not quite correct.Given these difficulties in student learning this aspect of chemical biology, researchers recommended enhancing the learning of DNA and protein structures through the use of three-dimensional physical models [2-4]. Herman et al.[5] and Bain [6] reported that concrete visual models that can be easily manipulated, play an important role in capturing the interest of students at both high school and undergraduate levels and encouraging more sophisticated thinking about the tangible molecular world.It should be noted that one obvious limitation to the widespread use of physical models is their high cost and limited availability. To provide our students with an easy access to a useful learning tool, we had developed physical models of ordered structures of the B-form DNA, protein a-helix, and b-pleated sheet made from computer-printed transparency film cut-outs. We used the already-assembled DNA double helix with two central axes (made from straight wires) [7] to teach students, medical as well as graduate bioscience, to learn the essential structural details of DNA and their role when interacting with drugs and proteins using the hydrogen bond donor and acceptor groups on the bases and the electrostatic char...

From our teaching of the contractile unit of the striated muscle, we have found limitations in using textbook illustrations of sarcomere structure and its related dynamic molecular physiological details. A hand-held model of a striated muscle sarcomere made from common items has thus been made by us to enhance students' understanding of the sliding filament mechanism as well as their appreciation of the spatial arrangements of the thick and thin filaments. The model proves to be quite efficacious in dispelling some alternative conceptions held by students exposed previously only to two-dimensional textbook illustrations and computer graphic displays. More importantly, after being taught by this hand-held device, electronmicrographic features of the A and I bands, H zone, and Z disk can be easily correlated by the students to the positions of the thick and thin elements relatively sliding past one another. The transverse expansion of the sarcomere and the constancy of its volume upon contraction are also demonstrable by the model.

Instructions are given for building physical scale models of ordered structures of B-form DNA, protein ahelix, and parallel and antiparallel protein b-pleated sheets made from colored computer printouts designed for transparency film sheets. Cut-outs from these sheets are easily assembled. Conventional color coding for atoms are used for both types of biopolymers. Arrows facilitate following chain direction for the polypeptides. For DNA, the 5 0 to 3 0 direction is guided by a 5 0 phosphate group and a free hydroxyl group. Important chiral centers, for example, a-carbon, deoxyribose C1 0 , are easily made. The main advantages of this version of DNA are the proportional major and minor grooves as in the actual molecule. More importantly, because of transparency of the film one can see successive base-pair stacking very clearly and also the sense of relative base-pair rotation. Because of the introduction of two central metal wire axes, the model of B-form DNA can be twisted to give a rather good representation of A-form and even a semblance of a left-handed helix. The models of secondary structure of protein allow a better insight into the axial alignment of side chains, the formation of hydrogen bond, the handedness of the a-helix, and the backbone connection between the b-strands. Students taught by these models understand 3D features of the biopolymers better than from textbook illustrations, computer graphic representations, and even common paper and plastic versions.Keywords: biomolecular models, DNA, protein alpha-helix, protein beta-sheet.Biophysical chemistry and chemical biology will play a crucial role in the post-genomic era. Fundamental understanding of the three-dimensional structures of the macromolecules and their folding, for example, DNA and protein, may make the students better understand biology at the molecular level and may facilitate their pursuits of advanced studies. Generally, polypeptide chains, protein a-helix and b-sheet, polynucleotide chain, and B-form DNA are common biochemical structures taught to beginning students. In routine classroom teaching, twodimensional depictions in textbooks and three-dimensional computer-generated presentations are often used to show students these molecular structures. We have found that many students fail to grasp three-dimensional details when DNA and protein structures are introduced in these ways. Several physical models of DNA and protein made of paper, wooden, metallic or plastic materials have been developed for teaching purposes [1][2][3][4][5][6][7][8][9][10]. These have features useful for illustrating certain important structural aspects of these molecules. However, each of these models has a number of limitations. For example, the ball-and-stick and the space-filling models, while illustrating the molecular structure in atomic detail, are usually expensive and not easy to construct. Some of the existing models may be easy to acquire and assemble, but they are not to the scale and are too abstract as representations. Most use opaque material...

Basic life support (BLS) knowledge is a necessity for nursing students, as they have to deal with cardiac arrest events during their professional career. Existing studies indicate poor BLS knowledge among health science students, including nursing students. Learning BLS requires an understanding of basic sciences, such as anatomy, physiology, and biochemistry, subjects perceived to be difficult, resulting in misconceptions. Hence, a multimedia-aided instruction on BLS, supplemented with cooperating learning groups, was developed to assist nursing students in gaining correct BLS knowledge. A pretest-posttest designed for single cooperating groups was employed to evaluate students’ achievements. Sixty-five undergraduate nursing students took the pretest and posttest that consisted of 10 open-ended questions, each designed to evaluate an aspect of their BLS knowledge. The results show significantly more students (60 vs. 20%) answered more questions correctly on the posttest compared with the pretest ( P value <0.05, Wilcoxon signed-rank test). Thus the multimedia-aided instruction package enhanced undergraduate nursing students’ understanding of BLS and also assisted to generate a positive perception of multimedia-aided instructions, supplemented with a cooperating learning group.