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Scientist P. Levene discovered that a nucleotide is made of three parts: a nitrogenous base, a sugar and a phosphate.
Levene thought that DNA was shaped like a coiled spring, and that the nucleotides were linked together by phosphate groups. -
In 1869, Friedrich Miescher discovered a completely new substance after many tests and named it "nuclear." It will demonstrate that the nucleus is found in many different cells. -
Phoebus Levene's tetranucleotide hypothesis [1] proposed that DNA was composed of repetitive sequences of four nucleotides. [2] Levene developed this hypothesis in 1910 and was very influential for the next three decades. -
It was one of the first experiments to demonstrate that bacteria were capable of transferring genetic information through a process called transformation. -
Chargaff's rule, formulated by Erwin Chargaff in the late 1940s, deals with the quantitative relationship of the nitrogenous bases that make up DNA in the form of nucleotides.[1] It was one of the bases of James Watson and Francis Crick to postulate the theory of the double helix of DNA. -
Oswald Avery, Colin MacLeod and Maclyn McCarty showed that DNA (not proteins) can transform the properties of cells, elucidating the chemical nature of genes. -
Avery made a culture of pneumococcus type S. He disrupted the cells (breaking the cell membrane) to obtain a solution or cell extract.[1][3]
Avery and colleagues managed to separate the cell extract from its macromolecular components and then tried to understand which of these substances could transform avirulent R bacteria into virulent S bacteria. -
He used bacteriophages, which are viruses that infect bacteria, to determine which part of the virus entered the bacterial cell and transmitted the viral genetic information. Bacteriophages are composed almost entirely of DNA and proteins. -
DNA has two strands that twist together and form a coil similar to a spiral staircase called a helix. The four basic components of DNA are nucleotides: adenine (A), thymine (T), guanine (G) and cytosine (C).