Explore an antiparallel double helix with two sugar-phosphate backbones, complementary base pairs and grooves. Change GC content and helical twist, then open the base pairs to inspect hydrogen bonding.
• 3D scene parts: Strand 1 sugar-phosphate backbone; strand 2 sugar-phosphate backbone; complementary base pairs; major and minor groove guide. • Controls: Displayed base-pair count (10–30 bp); GC fraction (0–1 fraction); Helical turn size (9–12 bp/turn); Separate base pairs (0–1 illustrative). • Live readouts: GC base pairs (bp); AT base pairs (bp); Hydrogen bonds; Displayed helix turns. • Guided experiments: All AT; All GC. • Four tabs (visual laboratory, curves and measurements, experiments, learn and assess), a model-verification run, a timestamped event log and a trial report.
GC pairs = round(N·GCfraction) AT pairs = N − GC pairs Hydrogen bonds = 3·GC pairs + 2·AT pairs Turns = N / (bp per turn)
Molecular geometry, organelle dimensions and animation time are enlarged and illustrative. Colors identify structures rather than natural tissue color. This is a conceptual teaching model, not a cell physiology predictor. Base counts are exact for the displayed representative sequence. Twist is user-controlled, not a thermodynamic or melting calculation. Try the preset experiments, then compare the live readouts with the equations.
No. Geometry is enlarged and time is a teaching playback scale.
Three.
Molecular geometry, organelle dimensions and animation time are enlarged and illustrative. Colors identify structures rather than natural tissue color. This is a conceptual teaching model, not a cell physiology predictor. Base counts are exact for the displayed representative sequence. Twist is user-controlled, not a thermodynamic or melting calculation.