DNA structure discovery and importance is discussed here. DNA is the acronym for deoxyribonucleic acid, usually 2′-deoxy-5′-ribonucleic acid. DNA is a molecular code used in cells to form proteins. It is considered a genetic model for an organism because every cell in the body that contains DNA has these instructions, which allow the organism to grow, repair and reproduce.
A single DNA molecule is formed as a double helix made up of two strands of nucleotides that are linked together.
Each nucleotide consists of a nitrogenous base, a sugar (ribose) and a phosphate group. The same 4 nitrogenous bases are used as the genetic code for each strand of DNA, regardless of the organism from which it originates. The bases and their symbols are adenine (A), thymine (T), guanine (G) and cytosine (C). The bases on each strand of DNA are complementaryto each other. Adenine always binds to thymine; guanine always binds to cytosine. These bases meet at the heart of the DNA helix. The skeleton of each strand is composed of the deoxyribose and phosphate group of each nucleotide. The carbon number 5 of ribose is covalently linked to the phosphate group of the nucleotide. The phosphate group of a nucleotide binds to the carbon number 3 of the ribose of the next nucleotide. The hydrogen bonds stabilize the shape of the propeller.
The order of the nitrogenous bases has a significance, coding for the amino acids which are joined together to make proteins.
DNA is used as a template to produce RNA through a process called transcription . RNA uses molecular machines called ribosomes, which use code to make amino acids and join them to make polypeptides and proteins. The process of making proteins from the RNA model is called translation.
German biochemist Frederich Miescher first observed DNA in 1869, but did not understand the function of the molecule.
In 1953, James Watson, Francis Crick, Maurice Wilkins and Rosalind Franklin described the structure of DNA and proposed how the molecule could code for heredity. While Watson, Crick and Wilkins received the Nobel Prize in Physiology or Medicine in 1962 “for their discoveries concerning the molecular structure of nucleic acids and their importance for the transfer of information on the alive one”, the contribution of Franklin was neglected by the Nobel committee.
Importance of knowing the genetic code
In the modern era, it is possible to sequence the entire genetic code of an organism. One consequence is that differences in DNA between healthy and sick individuals can help identify a genetic basis for certain diseases. Genetic testing can help identify if a person is at risk for these diseases, while gene therapy can correct certain problems in the genetic code. Comparing the genetic code of different species helps us understand the role of genes and allows us to trace the evolution and relationships between species.
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