Laboratory Report 6 6 Ubiquity of Bacteria A. Results 1. After examining your TS
ID: 257925 • Letter: L
Question
Laboratory Report 6 6 Ubiquity of Bacteria A. Results 1. After examining your TSA and blood gar plates, record your results in the following table and on a simi- t instruictor has drawn on the chalkboard. With respect to the plates, we are concerned ve evaluation of the degree of contamination and differentiation as to whether the organ- your restu ar table that your isms are bacteria or molds, Quantify your recording as follows 0 no growth + to 10 colonies ++11 +++51 to 100 colonies to 50 colonies++over 100 colonies After shaking the tube of broth to disperse the organisms, look for cloudiness (turbidity). If the brot turbid, record + in the las Is clear, no bacterial growth occurred. Record no growth as 0. If the tube is column. BROTH COLONY COUNTS ATE EXPOSURE METHOD STUDENT INITIALS Result Mold Source TSA Blood AgarExplanation / Answer
Molds generally grow on solid or non-liquid substratum whereas bacteria grow on a variety of substratums ranging from liquid broths to solidified culture plates. Since both TSA agar and blood agar plates are solid in nature, both bacteria and molds have the capability to grow over them. However, molds generally do not grow over blood-agar plates since the blood-agar system is a highly selective and differential medium. Since molds cannot utilize blood cells for their nourishment, the blood-agar plates for molds would always show negative or zero growth.
On the other hand, there are multiple type of bacteria which routinely grow on both TSA plates and blood-agar plates. Initially the growth periods would be less and few colonies would be obtained but the colony count would increase after 24 hours. The number of colonies can be counted manually or using a colony counter and noted down as observed.
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