A petri plate is given to you with 80 colonies on it. I tell you that I did five 10x dilutions and then plated 0.1 ml from my last tube to get 80 colonies on a plate. How many living bacteria per ml were in that original sample? Draw out (or describe) all of the dilutions I would have done to get this number. 7b. Again, I have a plate with 80 colonies on it, but I tell you that I did one 100x dilution and two 10x dilutions before I plated that 0.1ml from my last tube. How many living bacteria per ml were in that original sample? Draw out (or describe) all of the dilutions I would have done to get this number.
Microscopic examination
The analysis of minute organisms, cellular organization of any biological structure, and composition of body fluids with the help of a microscope is known as microscopic examination. The magnification of specimens or samples under study helps in attaining a clearer picture of it.
Gram Staining
Named after Hans Christian Gram, a Danish bacteriologist, Gram stain is one of the most powerful staining techniques within microbiology. This technique was introduced in 1882 to identify pneumonia-causing organisms. The Gram staining technique uses crystal violet or methylene blue as primary staining colors to distinguish gram-positive from gram-negative organisms. Under a microscope, the gram-positive organisms appear purple-brown, retaining the primary color. Gram-negative organisms appear pink or red as they do not acquire the color of the primary stain.
7a. A petri plate is given to you with 80 colonies on it. I tell you that I did five 10x dilutions and then plated 0.1 ml from my last tube to get 80 colonies on a plate. How many living bacteria per ml were in that original sample? Draw out (or describe) all of the dilutions I would have done to get this number.
7b. Again, I have a plate with 80 colonies on it, but I tell you that I did one 100x dilution and two 10x dilutions before I plated that 0.1ml from my last tube. How many living bacteria per ml were in that original sample? Draw out (or describe) all of the dilutions I would have done to get this number.
please include drawings. thank you
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