Required Lab Report 4 Selected Questions From Exercise On Extracellular Enzymes Using Starch Milk Casein And Dnase M 1 (106.34 KiB) Viewed 105 times
Required Lab Report 4 Selected Questions From Exercise On Extracellular Enzymes Using Starch Milk Casein And Dnase M 2 (106.34 KiB) Viewed 105 times
Required Lab Report 4 Selected Questions From Exercise On Extracellular Enzymes Using Starch Milk Casein And Dnase M 3 (106.34 KiB) Viewed 105 times
Required LAB REPORT 4- Selected questions from exercise on extracellular enzymes using starch, milk (casein) and DNase media. (In your results, do not just say positive or negative reaction for the 3 different bacteria on the 4 different media. Explain the color / media changes that are occurring and explain what is happening biochemically. You are responsible for knowing about the theory behind all 3 media as well as the results of all 3 unless told otherwise.) Bacteria being used in these exercises will include: Bacillus subtilis, E. coli, S. aureus, S. epidermidis, (and Serratia marcescens will get a mention). In class you will get further instructions. Q1. Bacteria produce extracellular enzymes. What role do these extracellular enzymes play in bacterial metabolism? Q2. How might the results obtained in exercises such as this one be used for the identification and/or classification of bacteria? Q3.Suppose you had poured iodine on your plate and noticed clearings in the uninoculated area, as well as around both of your transferred cultures? What are some possible explanations for this occurrence? Was the integrity of the exercise compromised? What kinds of things might be done to avoid this problem in the future? Q4. Is it acceptable to read a positive test before the incubation time is completed? Why is this not the case in a starch agar assay? How about an early negative result? Q5. Why is it advisable to use a positive control along with the bacterial organisms that you are testing? Q6. With the toluidine blue agar mentioned in class, what reaction is being tested for here? What kind of dye is toluidine blue? If the medium turns from blue to pink, what does that mean biochemically?
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