Question #1: In 1835, Bassi showed that a fungus caused a silkworm disease, and in 1865 Pasteur discovered that a protozoan caused another silkworm disease. Why do we use Koch's postulates instead of Bassi's or Pasteur's postulates?
Answer #1: Koch was the major mind in establishing that microorganisms cause a specific disease. He was able to prove that certain bacteria was present in the blood of the infected person or animal, but the presence of the bacteria could have been caused by the disease. Koch proved that certain infectious diseases are caused by certain microorganisms that can be isolated and cultures onto a media. The requirements Koch established are that the same pathogen must be present in every case of the disease, the pathogen must be isolated from the host and grown in a pure culture, the pathogen in the pure culture must cause the disease when it is inoculated into a healthy lab animal, and finally the pathogen must be isolated from the animal and must be shown to the original organism. Bassi and Pasteur were not able at that time to correlate the pathogen with the specific disease.
Question 3: In 1884, Hans Christian Gram described a method of staining bacterial cells while not staining surrounding animal tissues; however, he thought the staining method he developed was faulty because not all bacteria stained. In a letter to the editor of the journal in which Gram published his findings, write your response to Gram's concern.
Answer 3: Dear Editor, when staining bacteria I first heat the smear and cover with a basic purple dye, after that short time the purple dye is washed off and the smear is then colored with iodine. After the iodine is placed certain cells become purple and some become dark violet. The slide is decolorized to remove the purple from some cells but not from all. Safranin is then applied. Some bacteria were seen until