DNA and mRNA
Two types of nucleic acids are found within the cells of living organisms; DNA and RNA. These two have structural and functional differences between them.
DNA
DNA or deoxyribonucleic acid is the basic genetic material of major life forms, except for plant viruses, bacteriophages and some other viruses in which DNA is absent or any variation of double-stranded DNA is present. In eukaryotic cells, DNA occurs as a long double-stranded helical structure present in the nucleus. Watson and Crick proposed its double-stranded helical structure.
DNA is made up of three different types of compounds:
Sugar Molecules: Molecules present in DNA are pentose sugars, deoxyribose sugars.
Phosphoric acid
Nitrogenous base
There are four nitrogenous bases divided into purines and pyrimidines.
Purines: These are nitrogen-containing compounds with a bicyclic structure. Adenine and guanine are two types of purines present in DNA.
Pyrimidines: These are monocyclic structures. They include cytosine and thymine.
There is some consistency in the DNA structure, known as Chargaff’s base ratio. The model proposes equal amounts of purines and pyrimidines. The amount of adenine is equal to the amount of thymine in DNA. It also states that the basal ratio (A = T)/(G≡C) may vary across animal groups; however, it is constant within a species.
Gene
“mRNA” stands for “messenger ribonucleic acid”. It is synthesized in the nucleus as the complementary strand of DNA. mRNA has all the basic characteristics of RNA. Except for some characteristic differences, RNA is similar in composition to DNA. The sugar molecule present in RNA is ribose, and in the four nitrogenous bases, thymine is replaced by uracil. In RNA, the content of purines and pyrimidines is not an essential factor. In the case of RNA, the base ratio of Chargaff is also ineffective. There are three types of RNA; mRNA, rRNA and tRNA.
mRNA is formed as the complementary strand to one of the two strands of DNA. So it carries the same information as DNA in that particular part, except instead of thymine, uracil is present. Immediately after synthesis, it is moved out of the cytoplasm from the nucleus, where it is deposited in some ribosomes, where it aids in the process of protein synthesis.
The main function of mRNA is to carry genetic information from chromosomal DNA into the cytoplasm for protein synthesis. This is why Jacob and Monad in 1961
The reason this RNA is named messenger RNA. The life span of mRNA in prokaryotic cells is very short. It disappeared after a few translations.
Summary:
DNA is composed of deoxyribose while mRNA is composed of ribose.
DNA contains thymine as one of two pyrimidines, while mRNA contains uracil as its pyrimidine base.
DNA is present in the nucleus while mRNA diffuses into the cytoplasm after synthesis.
DNA is double-stranded while mRNA is single-stranded.
mRNA is short-lived, while DNA has a long lifespan.
