Question

Why was DNA originally called nuclein?

Answer 1

DNA is the carrier of genetic information and occurs in all the living cells and is capable of self replication. A basic unit of DNA is a nucleotide which has three components- a nitrogenous base, a pentose sugar (deoxyribose), and a phosphate group. The nitrogenous bases are of two types: Purines (Adenine and Guanine) and Pyrimidines (Cytosine, Thymine, and uracil). The nitrogenous base and the deoxyribose sugar are joined together with N-glycosidic linkages. They together form a nucleoside. When a phosphate group is linked to 5’-OH of a nucleoside through phosphodiester linkage, a corresponding nucleotide is formed. DNA is actually a polynucleotide chain.

Complete answer:
A nucleic acid is a long molecule made up of smaller molecules called nucleotides. Nucleic acids were discovered in 1868, when 24 old Swiss physician Friedrich Miescher isolated a new compound from the nuclei of white blood cells. This compound was neither a protein nor lipid nor a carbohydrate; therefore, it was a novel type of biological molecule. Miescher named his discovery "nuclein," because he had isolated it from the nuclei of cells. Today, this nuclein is named DNA. This is the actual reason why DNA was originally called nuclein.

Note:
DNA and RNA are the two hereditary molecules that are found in living cells. RNA are single stranded structures that are found in many primitive organisms and especially viruses. It is also formed from DNA (mRNA) during transcription processes. RNA is susceptible to mutations. On the other hand, DNA is a double helix structure which is relatively stable and hence, it is a better carrier of genetic information in terms of carrying the genes, but a drawback from the evolutionary point of view since it resists mutations and mutations are the backbone of evolution.