DNA – Deoxyribonucleic acid, is the hereditary material present both in prokaryotic and eukaryotic cells and is located within the nucleus of the cell. Every single cell, except red blood cells, contain a copy of our DNA and are inherited by our parents. It is the double helix, a biological molecule, composed of two single strands, which are held together by hydrogen bonds and consists of four types of nitrogen bases namely – adenine (A), cytosine (C), guanine (G), and thymine (T). The structure of this double helix DNA molecules is similar to that of a twisted ladder.
Also, read DNA Structure
Evolution of DNA
As we all are aware, scientists James Watson and Francis Crick discovered DNA and also won a Nobel Prize in the year 1962 for their discovery of the structure of DNA. In reality, the DNA molecule was discovered decades before. The story of DNA’s discovery began in the early 1950s and was first identified by the famous Swiss chemist named Johann Friedrich Miescher during his research on the white blood cells. During his experiments to study more about the composition of the white blood cells, he noticed that these DNA molecules dissolved in the alkali solution and when acid was added, this molecule got separated.
From his observations, he came to the conclusion that this DNA molecule had unexpected properties and is different from other protein molecules. Therefore he called this mysterious substance as ‘nuclein’ as it was obtained from the cell nucleus. After this conclusion, for many years, scientists continued to believe that proteins were the hereditary material. Later in the year 1881, a German biochemist, Albrecht Kossel identified nuclein as nucleic acid and named it has the deoxyribonucleic acid (DNA).
Since proteins and DNA were closely linked, let us understand how DNA is able to produce proteins.
How DNA Produces Proteins?
One of the major features of DNA is that it produces proteins. These proteins are crucial in rendering a definite structure to bones and other tissues, bringing about transportation of materials throughout the body (iron), cause movement of materials from one to another cell, act as hormones regulating the functions of the body, enzymatic role in chemical reactions and acts as antibodies fighting against diseases hence proteins are important cells of the body.
Proteins are made with the unzipping of DNA where the nucleotides cling to the open side of the ladder for the formation of messenger RNA or mRNA and vary slightly in its chemical structure compared to the DNA, supporting it to acquire the genetic code from the nucleus to the cytoplasm. The mRNA binds with ribosomes in the cytoplasm wherein each codon of mRNA in the ribosome is linked with the amino acids for which the codon codes. As the codon reading occurs sequentially, an assemblage of amino acids in the same order takes place, resulting in the formation of a protein. Hence different portions of DNA can successfully produce different types of proteins. As per modern genetics, many a time, it is the coordinated activities of a few genes that determine the proteins.
This was a brief introduction to Evolution of DNA. Stay tuned with BYJU’S to know more about the DNA, its structures and functions and other related concepts in biology.