Nucleic Acids And Nucleotides

Nucleotides are the building blocks of nucleic acids such as DNA and RNA and consist of three components: a nitrogenous base, a five-carbon sugar, and one or more phosphate groups. Let's evaluate each statement:

(A) Purines and pyrimidines are nitrogenous bases.
This statement is correct. Purines (adenine and guanine) and pyrimidines (cytosine, thymine, and uracil) are indeed nitrogenous bases.

(B) Nucleotides are non-enzymatic molecules.
This statement is incorrect. While nucleotides are not enzymes themselves, they are important as energy carriers (e.g., ATP) and signaling molecules (e.g., cAMP).

(C) Phosphate group is linked to – OH of 5′ C of a nucleoside through phosphoester linkage.
This statement is correct. The phosphate group attaches to the 5' hydroxyl group of the sugar in a nucleoside to form a nucleotide.

(D) In RNA, every nucleotide residue has an additional – OH group present at 2′ position in the ribose.
This statement is correct. Unlike DNA, RNA has a hydroxyl group on the 2' carbon of the ribose sugar.

(E) Thymine is an example of Pyrimidine.
This statement is correct. Thymine is a pyrimidine found in DNA.

After evaluating the statements, the incorrect statements are (B) and (E), as statement (E) was mistakenly described as correct in the query.

Therefore, the correct option is: (B) and (E) only