DNA Helix Structure (2D)

This flattened companion to the 3D DNA helix simulator renders the same double-helix structure as a scrolling ladder diagram: two antiparallel sugar-phosphate backbones traced as out-of-phase sinusoids, offset asymmetrically so the wider gap on one side reads as the major groove and the narrower gap on the other as the minor groove, matching real B-DNA geometry of about 10.5 base pairs and 34 angstroms per full turn. Every rung is built from an actual generated base sequence and split into two correctly complementary halves under Watson-Crick pairing — adenine always opposite thymine with two hydrogen bonds, guanine always opposite cytosine with three — and clicking any individual rung mutates just that base pair while live counters track total base pairs, GC content and total hydrogen bonds. An unwind slider progressively flattens the helix into an open ladder the way helicase unwinds DNA ahead of replication, and speed, theme and pause controls mirror the 3D version.