A selection of Mechanical calculators: The basic operating principles of mechanical calculators changed little from the end of the 19th century to their obsolescence in the 1970s, though there were many developments in the mechanisms and the materials used.
Post. Share. Bacteriophages are viruses that infect bacteria. A bacteriophage can have a protein tail attached to the capsid (protein coat that envelopes the genetic material), which is used to infect the host bacteria.Scientists have long sought to uncover the structure and function of viruses. bacteriophage can have a protein tail attached to the capsid (protein coat that envelopes the genetic material), which is used to infect the host bacteria.
1 Viruses-Viruses are extremely small and consists of DNA with a protective coating of protein. 2  Diseases caused by viruses include influenza, the common cold, measles, yellow fever, and hepatitis. 3  Bacteria-Bacteria are small microorganisms. 4  They can cause diseases such as tuberculosis, cholera, typhoid fever, and tetanus. Bacteria-Bacteria are small microorganisms. 2  They can cause diseases such as tuberculosis, cholera, typhoid fever, and tetanus. 3  Parasites-Parasites are organisms that live off their hosts. 4  Some parasitic diseases include malaria, sleeping sickness, and scabies. 5  Fungi-Fungi are microorganisms such as yeasts and molds.