試題詳解

15. Which of the following descriptions about nucleotide and nucleic acid structures is(are) correct?
1. The double helix of DNA in the B-form is stabilized by covalent bonds between the 3' end of one strand and the 5' end of the other.
2. The double helix of DNA in the B-form is stabilized by nonspecific base-stacking interaction between two adjacent bases in the same strand.
3. In nucleotides and nucleic acids, syn and anti conformations relate to rotation around the phosphodiester bond.
4. C-5 of the pentose in nucleic acids is joined to a nitrogenous base.
5. The phosphodiester bond that joins adjacent nucleotides in DNA is susceptible to alkaline hydrolysis.
(A) 1 and 2.
(B) 2 and 3.
(C) 3 and 4.
(D) 2 only.

(E) 2 and 5.