Answer: Both deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are made up of nucleotides which consist of three parts: 1  Nitrogenous Base. 2  Purines and pyrimidines are the two categories of nitrogenous bases.3  Pentose Sugar. 4  In DNA, the sugar is 2'-deoxyribose. 5  Phosphate Group. 6  A single phosphate group is PO 4 3- .nswer: Both deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are made up of nucleotides which consist of three parts: 1  Nitrogenous Base. 2  Purines and pyrimidines are the two categories of nitrogenous bases.
AT A GLANCE: In 1440, German inventor Johannes Gutenberg invented a printing press process that, with refinements and increased mechanization, remained the principal means of printing until the late 20th century.
From printing to typing. When Johann Gutenberg invented the printing press with loose type in the 15th century, he cleared the way for the gradual proliferation of the printed word. It would seem an obvious second step to use the printing technology to create a machine that could take over the cumbersome task of hand writing.