1.16 Aseptic Techniques and Cell Culture

Question 1

Aseptic technique eliminates ___.

Answer 1

contaminants

Question 2

Aseptic technique involves the ___ of equipment and culture ___.

Answer 2

equipment, mediums

Question 3

Which two substances can be used to start microbial cultures?

Answer 3

agar and broth

Question 4

Most animal cell cultures use and require ___ ___ from serum.

Answer 4

growth factors

Question 5

What are growth factors?

Answer 5

Growth factors are proteins that promote growth and proliferation and are essential to the growth of most animal cells

Question 6

In culture, primary cell lines can divide a ___ number of times, whereas ___ cell lines have no division limit.

Answer 6

limited, tumour

Question 7

Liquid microbial cultures must be plated before the number of __-___ units can be counted, and the total ___ count estimated.

Answer 7

colony-forming, cell

Question 8

Before you even try to count the cells in a culture, a ___ dilution should be conducted to reduce the number of units in a ___ way, so that the number of cell scan be ___ up to find the ___ number of cells in the culture, after counting.

Answer 8

log, predictable, scaled, total

Question 9

Haemocytometers can provide an estimate of the ___ cell count, and the ___ cell count.

Answer 9

total, viable

Question 10

Haemocytometers are set up with…

Answer 10

trypan blue dye,

Question 11

Trypan blue dye is taken in by ___ cells, but not by ___ cells.

Answer 11

dead, living

Question 12

What is the percentage viability of a cell sample?

Answer 12

The % of living cells (living/total x 100)

Question 13

A haemocytometer has a bunch of squares. When using a haemocytometer, you must count ___ to prevent errors. You should ignore the cells that overlap on ___ sides, but include those that overlap on the other ___ sides, in order to avoid ___-___.

Answer 13

systematically, two, two, over-counting

Question 14

The total number of cells in a culture/stock can be calculated by scaling up the number of cells in a ___, assuming you know its ___.

Answer 14

haemocytometer, volume.
(eg 20 cells in 0.1 mm3,
so 20,000 in 0.1 cm3,
so 200,000 in 1 cm3)

distance is 1 dimensional (1mm X 10 = 1 cm)
area is 2 dimensional (1mm2 X 100 = 1cm2)
volume is 3 dimensional (1mm3 X 1000 = 1cm3)

Question 15

Name some downsides to using haemocytometers.

Answer 15

not necessarily accurate - only provides estimate.
time consuming.
subject to human error