biology·NCERT Class 12·Molecular Basis of Inheritance
DNA Double Helix
Medium+80 XP🧬
Watson and Crick used X-ray data to build the first model of DNA — a twisted ladder with base pairs as rungs. Unwind the helix in 3D and pair the bases yourself.
›DNA is a right-handed double helix; pitch = 3.4 nm; 10 base pairs per turn.
›Chargaff's rule: %A = %T and %G = %C in double-stranded DNA.