Question

Which is not applicable to RNA
A. Chargaff's rule
B. Complementary base pairing
C. 5’phosphoryl and 3’ hydroxyl ends
D. Heterocyclic nitrogenous base

Answer 1

DNA and RNA are genetic materials that are transferred from parents to the next generation. DNA stands for deoxyribonucleic acid and RNA stands for ribonucleic acid. RNA contains ribose sugar and it is single-stranded.

Complete answer: In RNA, nitrogenous bases, viz. cytosine, uracil, adenine and guanine are present. A hydrogen bond binds guanine with cytosine and uracil with adenine. They are known as complementary base pairs. In RNA, a 2' hydroxyl end is present and in DNA, a 3' hydroxyl end is present. So, 5' phosphoryl and 3' hydroxyl do not belong to RNA.
a) Chargaff's rule: In the cell of any organism, there is a ratio of 1:1 pyrimidine and purine bases in DNA. This rule states that the amount of guanine should be equal to cytosine and the amount of adenine should be equal to thymine. It is applicable for two stranded molecules, for e.g, DNA. Hence, this rule applies to DNA and some double-stranded RNA.
b) Complementary base pair: In genetic material, there are five types of nitrogenous bases.
Pyrimidine:- cytosine, thymine and uracil
Purine:- adenine and guanine
c) Heterocyclic nitrogenous bases: Ring compounds have more than two types of atoms. Nitrogenous bases uracil, thymine, adenine, guanine and cytosine are heterocyclic nitrogenous bases. DNA and RNA are both genetic materials. Deoxyribose has one oxygen less than ribose sugar and DNA contain thymine but RNA contains uracil in place of thymine.
Hence, the correct answer is option C.

Note: There are three types of RNA’s: mRNA, tRNA and rRNA. They play an important role in translation, i.e. protein synthesis. mRNA acts as a template on which tRNA comes and binds in translation. DNA to RNA and RNA to protein is an example of the central dogma of molecular biology.