As we know that chemical bond is the key to the formation of chemical compounds, it is a form attraction that is formed between ions, molecules, and atoms. The hydrogen bond is a type of chemical bond that is formed due to the strong interaction between 2 permanent dipoles, a big difference is seen in the electronegativities between hydrogen and any compounds like nitrogen, fluorine, and oxygen. When these compounds are joined with their lone pairs of electrons, strong electrostatic forces is seen between molecules.
When a hydrogen atom is linked to a highly electronegative atom in a molecule, it develops the capacity to attract the shared pair of electrons and hence this end of the molecules becomes slightly negative while the other end becomes slightly positive. Hydrogen bond may be intramolecular or intermolecular depending on the nature of acceptor or donor, environment and structure bond is formed.
Let us look where hydrogen bond plays a vital role in the living organism.
As we are aware, the main constituent of the living organism is DNA. DeoxyriboNucleic Acid (DNA) is the main medium of carrying the genetic instructions used in the growth, functioning, development, and reproduction of all the living organisms including microorganisms. The DNA molecule is formed of 2 chains that twist around each other to create a double helix model. These strands are individual and run opposite to each other. The DNA double helix model is stabilized originally by 2 forces that exist between them: base-stacking interactions among aromatic nucleobases and the essential hydrogen bonds between nucleotides.
As we know the DNA model features, one variety of nucleobase on one of the strands and another type of nucleobase on the other strand. When these nucleobases are bound to each other, it is referred to as complementary base pairing. Purines are the main component responsible for the formation of pyrimidines in DNA from hydrogen bonds. It is witnessed that Adenine bonds with thymine in 2 hydrogen bonds, and the compound cytosine bonds to guanine in 3 hydrogen bonds. This arrangement in which 2 nucleotides binds together across the DNA model is called a Watson-Crick base pair.
Since hydrogen bonds can be broken and rejoined easily and are covalent. The double helix DNA can be pulled apart and be separated at a high temperature or by a mechanical force. As a result of the information in the double-helix, stranded sequence DNA can be duplicated and is important in the DNA replication process. This reversible and particular interaction among complementary base pairs is an important function of DNA seen in all the living organisms.
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