​Given below are two columns depicting structural features (Column X) and the DNA/RNA conformation (Column Y).​

​Which one of the following options represents all correct matches between Column X and Column Y?​

• A. Left-handed

  • This describes Z-DNA, which is a left-handed helical structure.

  • Match: A → (iii) Z form

• B. Number of base pairs per turn is 10

  • The common B-DNA has about 10 base pairs per turn.

  • Match: B → (ii) B form

• C. The base pairs are off-centered

  • This is a feature of A-DNA, where the bases are tilted and displaced from the axis of the helix.

  • Match: C → (i) A form

• D. RNA double helix

  • RNA double helices resemble the A-form rather than B or Z forms.

  • Match: D → (i) A form

Information Booster:

• B-DNA: The most common DNA conformation under physiological conditions, right-handed, with ~10 bp per turn.

• A-DNA: A right-handed form of DNA, more compact with bases tilted and displaced from the helix axis. RNA double helices also resemble A-form.

• Z-DNA: A left-handed DNA helix with a zigzag backbone. It forms under specific conditions and is less common.

• RNA Double Helix: Due to the 2’-OH group on ribose, RNA favors the A-form conformation.