# cell concentrations

### #1

Posted 11 November 2009 - 06:35 PM

To start i have some cells with a concentration of 9.7 x107/ml.

I took 2ml of these cells and added 1ml of media to them.

What is the concentration?

If i then take iml of the above diluted cells and add a further 0.5ml of media what is the concentration of these cells now?

jay

### #2

Posted 11 November 2009 - 07:25 PM

To start i have some cells with a concentration of 9.7 x107/ml.

I took 2ml of these cells and added 1ml of media to them.

What is the concentration?

(9.7 x 10^7 cells times 2) divided by 3 ml.

If i then take iml of the above diluted cells and add a further 0.5ml of media what is the concentration of these cells now?

((9.7 x 10^7 cells times 2) divided by 3 ml) divided by 1.5 ml.

### #3

Posted 12 November 2009 - 11:31 AM

I am having some problems with determing the cells concentration.

To start i have some cells with a concentration of 9.7 x107/ml.

I took 2ml of these cells and added 1ml of media to them.

What is the concentration?

If i then take iml of the above diluted cells and add a further 0.5ml of media what is the concentration of these cells now?

jay

C1V1=C2V2 is your friend here!

(9.7*10^7)(2)=(C2)(3)

C2=6.5*10^7

Then do your next calculation from that.

### #4

Posted 25 February 2010 - 12:11 PM

@ Homebrew : I havent understood how have you calculated this below ? Can you explain me please, more importantly the second calculation. I haent understood it. Thank you

QUOTE (jsnts @ Nov 11 2009, 09:35 PM)

To start i have some cells with a concentration of 9.7 x107/ml.

I took 2ml of these cells and added 1ml of media to them.

What is the concentration?

(9.7 x 10^7 cells times 2) divided by 3 ml.

(9.7 x 10^7 cells times 2) divided by 3 ml.

QUOTE (jsnts @ Nov 11 2009, 09:35 PM)

If i then take iml of the above diluted cells and add a further 0.5ml of media what is the concentration of these cells now?

((

**9.7 x 10^7 cells times 2) divided by 3 ml) divided by 1.5 ml.**

### #5

Posted 25 February 2010 - 01:57 PM

@ Homebrew : I havent understood how have you calculated this below ? Can you explain me please, more importantly the second calculation. I haent understood it. Thank you

Your original concentration is 9.7 x 10^7 cells per ml. You took 2 ml of that, thus you now have

**9.7 x 10^7 times 2**, or 1.94 x 10^8 cells. You added 1 ml of media to them, so now the 1.94 x 10^8 cells are in 3 ml of volume, thus the concentration in cells per ml is 1.94 x 10^8 cells

**divided by 3 ml**, or 6.47 x 10^7 cells per ml.

Using similar reasoning for the second step, you start with 1 ml of a culture at 6.47 x 10^7 cells per ml (arrived at above, by solving

**(9.7 x 10^7 cells times 2) divided by 3 ml**), and add 0.5 ml of media to that. Thus, you now have 6.47 x 10^7 cells in 1.5 ml of volume, and the concentration is 6.47 x 10^7 cells

**divided by 1.5 ml**, or 4.31 x 10^7 cells per ml.