Question

2. You received a mixed culture and know that contains a specific blue/black forming bacterial colony. You decided to plate 0.1ml of the original culture on a specific plate that only allows for the growth of that particular microbe. You got the following plate. A Is this an example of a selective plate, differential plate, or both? Explain B. How many colonies do you count? Is this within accurate range? C. What is the O.C.D. of the stock/original culture?

I counted 25 colonies and I think that it is within an accurate range.

I feel like it is a selective plate because the organism appears to be isolation.

Answer 1

7 Mixed sample. Selective medium General pevepose nom selective medium (one species grows) (All species grow) So, visibly only one kind of colouration and pattern of growth is ob served SELECTIVE MEDIA- enables only a specific type of bacteria to grow.

MIXED SAMPLE General purpose Differential medium All species look (All species grow, but show similare) different reactions. Differential media - allows bacteria to show o different reactions (ie. colony colour)

A It is a selective plate - visibly only one kind ronies are growing Cas given in the question). As for differential plate, a number of species would have grown with different potterns are Colowe ations. B). No of colonies range from 28-30. c) Volume of original culture used ole to plate = 0.1 ml Soro. C.D (original culture density) on Colony Forming units/mL = 30x10 If taken, . = 300 cells/mL. no of colonies = 30 If no of colonies is as, O.C.D or CFU sal = 25 x 10 041 = 250 cells/me.
CFU/ml= (no of colonies/ ml plated)/ dilution factor

here dilution factor is not given so, not considered