DNA double helix (Watson–Crick model)डीएनए द्विकुंडलिनी (वॉटसन–क्रिक मॉडल)

NCERT Fig 5.3 · Class 12 Biology · Chapter 5 · interactive diagram

Parts and their functions

• Sugar–phosphate backbone (शर्करा–फॉस्फेट मेरुदंड) — Deoxyribose sugars joined by 3′–5′ phosphodiester links; bases point inwards.
• Adenine = Thymine pair (एडेनिन = थाइमिन युग्म) — A pairs with T by two hydrogen bonds (purine opposite pyrimidine).
• Guanine ≡ Cytosine pair (ग्वानिन ≡ साइटोसिन युग्म) — G pairs with C by three hydrogen bonds.
• Antiparallel strands (5′→3′ and 3′→5′) (प्रतिसमानांतर रज्जुक) — One strand runs 5′→3′, the other 3′→5′.
• Pitch 3.4 nm (one turn ≈ 10 bp) (पिच 3.4 nm (एक चक्कर ≈ 10 bp)) — Right-handed helix; one full turn is 3.4 nm and has about 10 base pairs.
• 0.34 nm between base pairs (क्षार युग्मों के बीच 0.34 nm) — Distance between two consecutive base pairs; stacked base pairs add stability.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 5.3. Report a mistake