Making ordered DNA and protein structures from computer‐printed transparency film cut‐outs
Bibliographic record
Abstract
Instructions are given for building physical scale models of ordered structures of B-form DNA, protein α-helix, and parallel and antiparallel protein β-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' to 3' direction is guided by a 5' phosphate group and a free hydroxyl group. Important chiral centers, for example, α-carbon, deoxyribose C1', 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 α-helix, and the backbone connection between the β-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.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.022 | 0.006 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".