Question

In RNA, nucleotides are bonded by
A) H bonds
B) Phosphodiester bonds
C) Ionic bonds
D) None of the above

Answer 1

Nucleotides are the basic building blocks of nucleic acids and consist of sugar molecules. In RNA, ribose sugar is present attached to a phosphate group and nitrogen contains bases like adenine, guanine, cytosine, uracil and thymine.

Complete answer:
Nucleotides present in RNA have a common structure which contains a phosphate group attached to a five membered pentose sugar i.e ribose and linked by phosphodiester bond.
So, the correct answer is option B phosphodiester bond.
Nucleotides are composed of three subunit molecules: a nitrogenous base, ribose or deoxyribose sugar and phosphate group (one to three molecules).
These are synthesized in vitro as well as in vivo.
RNA contains four bases: guanine, adenine, cytosine and uracil.
A phosphodiester bond is a covalent bond that contains phosphate groups which are negatively charged. They make the backbone of the strands of nucleic acid. In both DNA and RNA, the phosphodiester bond is the linkage between 5’ carbon atom of one ribose sugar molecule and 3’ carbon atom of another ribose molecule in RNA and deoxyribose in DNA.
A phosphodiesterase enzyme is responsible for the hydrolysis of phosphodiester bonds.

Note: The two ester bonds in the phosphodiester group are formed by the reaction of hydroxyl groups in phosphoric acid and a hydroxyl group of two other molecules. It is a condensation reaction as loss of water molecules generates each ester bond.