Question

Which one of the following is not able to form finally by the hydrolysis of DNA or RNA?
(A)Hexose sugar
(B)Phosphoric acid
(C)Purine
(D)Pyrimidine

Answer 1

Hint: As we know that DNA and RNA are the key macromolecules that are proof of the existence of life on this very planet earth. These molecules contain the genetic hereditary information within them that passes from adults to their fore springs. To know what product will be formed and what not, we are required to know about the structures of RNA and DNA.

Complete answer:
Deoxyribonucleic acids (DNA) and ribonucleic acid (RNA) are the macromolecules that contain the genetic material in living organisms, all the way from single celled bacteria, viruses to mammals like us
-DNA and RNA are made up of monomers known as nucleotides. These nucleotides combine together to form polynucleotides.
-Each nucleotide is made of 3 things: a five-carbon sugar, nitrogen containing ring structure known as nitrogenous base and at least one phosphate group. The sugar molecule being at the center is attached by a base to one of its carbon and the phosphate groups attached to one another.
-When DNA and RNA are hydrolyzed, it gives sugar, nitrogenous base and acids of phosphorus as products. Therefore we will check the given compounds, whether they are one of them or not.
(A)Hexose sugar: It is a six-carbon sugar whereas nucleotide consists of only 5-carbon sugar. Hence this will not be formed as the final product.
(B)Phosphoric acid: Since DNA consists of phosphate groups which on hydrolysis get released as phosphoric acids. Hence this will be one of the final products.
(C)Purine: Since Purine is the nitrogenous base thereby it will also be a final product.
(D)Pyrimidine: Similarly Pyrimidine is nitrogenous base as well; hence this will also be the final product.

From the above data we conclude that (A) Hexose sugar will not be able to form finally by the hydrolysis of DNA or RNA.

Note:
The sugar present in RNA or DNA is the pentose sugar and it is present in the furanose form.
-Both DNA and RNA contain 4 nitrogenous bases which are as follows:-
DNA: Adenine, guanine, thymine and cytosine
RNA: Adenine, guanine, uracil and cytosine