Show all calculations in a neat and organized manner be sure...

Show all calculations in a neat and organized manner. Be sure that I understand your logic. For your experiment, you must treat 1 x 10^9 cells with 5 nM cycloheximide (MW = 281.35). Cycloheximide is both toxic and expensive. You have counted the cells with a hemocytometer and found the following numbers when counting 5 "4x4" sections (each 4x4 is 0.004 µl) of a 1:10 dilution of your chlamy stock: 90, 103, 123, 99, 107. 1) What is the concentration of the initial Chlamy culture in cells/ml? _______________________ 2) How many mLs of cells of the culture must you use for the experiment? _____________________ 3) Describe how you will treat the cells with cycloheximide. Clearly show all calculations.

Transcript

00:01 So, for experiment, you must treat 1 x 109 -powered cells with 5 nm of cyclohexamide.

00:13 Cyclohexamide is both toxic and expensive.

00:16 You have counted the cell with a hemocytometer and found the following number.

00:20 So you have 4 x 4 sections.

00:24 So each square is 0 .04 ml.

00:27 And this is a 1 x 10 dilution of your calamine stock.

00:31 So, first of all, decide the concentration of the initial calamine culture.

00:35 So what you're going to do is you have to take an average.

00:39 So you have 5 numbers you have to take the average.

00:42 So the average equals 90 plus 103 plus 123 plus 99 plus 107.

00:59 Then you divide by 5.

01:04 So 522 divided by 5, you get 104 .4 cells in each of those squares.

01:16 Now, the next step, you can calculate your concentration.

01:20 This is the diluted stock.

01:22 So the concentration will be the number of cell, 104 .4 cells, divided by the volume of the square.

01:30 According to the question, we know that 4 .4, the 4 x 4 section, has a volume of 0 .004 ml.

01:42 So we can actually, first of all, calculate, convert the ml to ml, because usually the culture is in cells per ml.

01:56 So 104 .4 cells divided by 0 .004 ml, multiplied by 1 ,000 ml on the bottom and 1 ml on top, because 1 ml equals 1 ,000 ml.

02:18 So this will actually equal 4 x 10 to the negative 6 ml.

02:29 So again, on the top is 104 .4 cells.

02:35 So this is the diluted concentration.

02:44 So after we calculate, it's 26 .1 x 10 to the 6th power cells per ml.

03:00 And we want to write it down in scientific notation.

03:04 Move the decimal over here, plus one here.

03:07 2 .61 x 10 to the 7th cells per ml.

03:14 So this is diluted.

03:16 Now we know that this culture is also a 1 to 10 dilution.

03:21 So the initial concentration is going to be the diluted stock, 2 .61 x 10 to the 7th cells per ml, multiplied by the dilution factor, which is 10.

03:41 So you get a 2 .61 x 10 to the 8th cells per ml.

03:52 So this is the initial concentration.

03:55 Second question.

03:57 How many ml of cell of the culture must you use for the experiment? so now we know that for the experiment, you need 1 x 10 to the 9th cell.

04:07 So you have a concentration of 2 .61 x 10 to the 8th cells per ml.

04:12 So the volume equals the total cell 1 x 10 to the 9th cells, divided by the concentration, 2 .61 x 10 to the 8th cells per ml.

04:29 So you need about 3 .8 ml of the stock to make a total of 1 x 10 to the 9th cell.

04:45 The next step, describe how you would treat a cell with cyclohexamide.

04:54 So now you know you want to make a 5 nm of cyclohexamide...