Which of the following statements are incorrect with respect to nucleotides?

(A) Purines and pyrimidines are nitrogenous bases.

(B) Nucleotides are non-enzymatic molecules.

(C) Phosphate group is linked to - OH of 5' C of nucleoside through phosphodiester linkage.

(D) In RNA, every nucleotide residue has an additional - OH group present at 2' position in the ribose.

(E) Thymine is an example of Pyrimidine.

Choose the correct answer from the options given below:

(B) and (D) only

The correct answer is Option (3) –(B) and (D) only

A nucleotide has three components – a nitrogenous base, a pentose sugar (ribose in case of RNA, and deoxyribose for DNA), and a phosphate group. There are two types of nitrogenous bases – Purines (Adenine and Guanine), and Pyrimidines (Cytosine, Uracil and Thymine). Cytosine is common for both DNA and RNA and Thymine is present in DNA. Uracil is present in RNA at the place of Thymine.

A nitrogenous base is linked to the OH of 1' C pentose sugar through a N-glycosidic linkage to form a nucleoside, such as adenosine or deoxyadenosine, guanosine or deoxyguanosine, cytidine or deoxycytidine and uridine or deoxythymidine.

When a phosphate group is linked to OH of 5' C of a nucleoside through phosphoester linkage,  a corresponding nucleotide (or deoxynucleotide depending upon the type of sugar present) is formed. The backbone of a polynucleotide chain is formed due to sugar and phosphates. The nitrogenous bases linked to sugar moiety project from the backbone.

In RNA, every nucleotide residue has an additional –OH group present at 2' -position in the ribose. Also, in RNA the uracil is found at the place of thymine (5-methyl uracil, another chemical name for thymine).

The nucleotides are known to be enzymatic molecules. For example, ribozymes are catalytic molecules. Also certain derivatives of nucleotides such as ATP, coenzyme A, nicotinamide adenine dinucleotide, etc., are important catalytic molecules that participate in various enzymatic processes.

Note : As per NTA, this is a PYQ. According to the question only statement B is incorrect . All other statements are correct and are given in ncert. So out of the given options no one is correct but here we have to choose one so we have marked option 3 but this is not a correct option.