Question

why does rna double helix take a form of the helix and not b form

Answer 1

Unlike double-stranded DNA, RNA is a single-stranded molecule in many of its biological roles and consists of a much shorter chain of nucleotides. The hydroxyl groups in the ribose backbone make RNA less stable than DNA because it is more prone to hydrolysis.

Answer 2

Answer:

RNA nucleobases pair predominantly by hydrogen bonding in the canonical Watson-Crick way, which links C and G by three and A and U by two hydrogen bonds. This results in right- handed double helices as secondary structure, e.g. an A-form RNA