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NEET2026BiologyChapterActual

Which of the following statements is incorrect regarding the salient features of the DNA double helix?

Options

  1. AThe two polynucleotide chains have anti-parallel polarity.
  2. BThe backbone is constituted by sugar-phosphate, and the bases project inside.
  3. CAdenine pairs with Thymine through three hydrogen bonds.
  4. DThe plane of one base pair stacks over the other, conferring stability to the structure.

Correct answer

C. Adenine pairs with Thymine through three hydrogen bonds.

Step-by-step solution

According to the Watson-Crick model of DNA double helix, Adenine pairs with Thymine through two hydrogen bonds, not three. Guanine pairs with Cytosine through three hydrogen bonds. The other statements are correct features of the DNA double helix: The two polynucleotide chains have anti-parallel polarity (one is 5' 3' and the other is 3' 5' ). The backbone is formed by sugar-phosphate, with nitrogenous bases projecting inwards. The plane of one base pair stacks over the other, which along with hydrogen bonds, provi

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