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The individual nucleotide monomers are chain-joined at their sugar and phosphate molecules, forming two 'backbones' (a double helix) of nucleic acid, shown at upper left. A nucleo tide is composed of three distinctive chemical sub-units: a five-carbon sugar molecule, a nucleobase (the two of which together are called a nucleo side ), and one ...
Phoebus Aaron Theodore Levene (25 February 1869 – 6 September 1940) was a Russian-born American biochemist who studied the structure and function of nucleic acids. He characterized the different forms of nucleic acid, DNA from RNA, and found that DNA contained adenine, guanine, thymine, cytosine, deoxyribose, and a phosphate group. [1]
Nucleic acids RNA (left) and DNA (right). Nucleic acids are large biomolecules that are crucial in all cells and viruses. [1] They are composed of nucleotides, which are the monomer components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid ...
DNA and ribonucleic acid (RNA) are nucleic acids. Alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life. The two DNA strands are known as polynucleotides as they are composed of simpler monomeric units called nucleotides.
At neutral pH, nucleic acids are highly charged as each phosphate group carries a negative charge. [7] Both DNA and RNA are built from nucleoside phosphates, also known as mononucleotide monomers, which are thermodynamically less likely to combine than amino acids. Phosphodiester bonds, when hydrolyzed, release a considerable amount of free energy.
However, Miescher's discovery played an important part in the identification of nucleic acids as the carriers of inheritance. The importance of his discovery was not apparent until Albrecht Kossel (a German physiologist specializing in the physiological chemistry of the cell and its nucleus and of proteins) researched the chemical structure of ...
Friedrich Miescher (1844–1895) discovered a substance he called "nuclein" in 1869. Somewhat later, he isolated a pure sample of the material now known as DNA from the sperm of salmon, and in 1889 his pupil, Richard Altmann, named it "nucleic acid". This substance was found to exist only in the chromosomes.
For polynucleic acids (DNA/RNA), the monomers are nucleotides, each of which is made of a pentose sugar, a nitrogenous base and a phosphate group. Nucleotide monomers are found in the cell nucleus. Four types of nucleotide monomers are precursors to DNA and four different nucleotide monomers are precursors to RNA.