Question

In: Biology

You have just joined a lab and have obtained a flask with J558L cells. You take...

You have just joined a lab and have obtained a flask with J558L cells. You take an aliquot of the cells, dilute the aliquot with Trypan Blue (1:1), and count the cells using a hemocytometer and obtain the following numbers:

	Transparent cells:	Blue cells:
Quadrant 1	52	1
Quadrant 2	60	3
Quadrant 3	58	2
Quadrant 4	51	2
Quadrant 5	57	1

1) What is the cell viability?

2) What is the density of the cells (living) in the culture?

Expert Solution

Answer)

Trypan blue dye when added to the cells, a live cell will pump it out and become transparent. Whereas dead cells will take the dye and stain blue.

Therefore all the transparent cells are live cells whereas blue cells are dead cells.

1. Total number of live cells/ transparent cells in 5 quadrants = 152 + 260 + 358 + 451 + 557 --------> 1,778 live cells .

2. Total number of dead cells or blue cells in 5 quadrants = 1 + 3 + 2 + 2 + 1 -----> 9 dead cells

What is the cell viability?

% cell viability = total number of live cells/ total number of cells.

Total number of cells = total number of live cells + total number of dead cells -----> 1778 + 9 ------ > 1787.

% cell viability = 1,778 live cells / 1787 total number of cells = 99.4 percent of cell viability.

2) What is the density of the cells (living) in the culture?

Answer)

1.viable cells per quadrant = 1778/ 5 -----> 355.6 cells per quadrant. 5 is the number of quadrants.

2. On average we obtained 355.6 live cells per quadrant.

3. Each quadrant can hold 0.0001 ml of culture. cell density = 355.6 / 0.0001 = 3.5 x 10⁶ live cells per ml.

4. We have diluted the sample with trypan blue 1:1. therefore the dilution factor is 2.

5. live cell density in the original medium = 3.5 x 10⁶ x 2 = 7 x 10⁶ live cells per ml.

6. therefore there are 7 x 10⁶ live cells per ml in the original media.

gladiator answered 1 year ago

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