Which is wrong about nucleic acids ?

Options

A. DNA is single stranded in some viruses
B. RNA is double stranded occasionally
C. Length of one helix is 45 `Å` in B-DNA
D. One turn of Z-DNA has 12 bases

Answer

C

Explanation

Length of one helix or the pitch per tum of helix is 34 `Å` in B-DNA, 25 `Å` in A-DNA and 46 A in Z-model of DNA. In Z-DNA sugar moieties are seen in opposite direction. So the 3-5 diester bond forms zig-zag structure in Z-DNA.