00:01
Question number one, how many microliter of original sample are required to produce a final dilution of 10 to negative 3 in a total volume of 45 ml? i report your answer in standard decimal notation around the two decimal places, if appropriate.
00:24
We also know that one microliter is 10 to negative 6 liter or 10 to negative 3 ml liter.
00:30
So in this case, we know that you have say x ml original sample and then divide by 45 ml liter.
00:42
And this equals 1 to 1000, which is 10 to negative 3.
00:50
So easily we can just do 1000 x equals 45 ml.
01:03
X equals 45 ml divided by 1000, you get 0 .045 ml liter.
01:14
But we also know that one microliter is 10 to negative 3 ml.
01:19
So this tells us that one ml is 1000 microliter.
01:25
So then this number multiplied by 1000, you get 45 microliter.
01:33
So this answer the first question.
01:34
So now the second question says a, right now here, 10 to negative 8 dilution is performed on a culture of bacteria in order to perform viable plate count.
01:50
From the dilution, 0 .1 ml of the solution is plated on solid media and 294 colony grow on the plate.
02:02
How many bacteria are in the single ml of the original culture? express answer to two decimal places using scientific notation.
02:11
So in this case, you're going to have to use this formula.
02:17
Original concentration equals number of cfu divided by the volume plated, multiplied by the dilution factor...