Question

Which of the following is not relevant to the structure of double helical DNA?

• A. The helix makes one complete spiral turn every 34A${}^o$.
• B. The diameter of the helix is 20A${}^o$.
• C. The distance between adjacent nucleotide is 3.4A${}^o$.
• D. The two adjacent sugar molecules joined with phosphate by phosphodiester bond.
• E. Each strand of helix has a backbone made up of alternating ribose sugar and phosphate.

Answer 1

Answer: (E)

The two DNA strands are known as polynucleotides since they are composed of simpler units called nucleotides. Each nucleotide is composed of a nitrogen - containing nucleobase - either guanine, adenine, thymine or cytosine - as well as a monosaccharide sugar called deoxyribose and a phosphate group.