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

sterilisation, 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, how should you count?

Answer 13

You should count systematically, ignoring the cells which overlap on two sides of the square (eg top and left) and including those which overlap on the other two, in order to avoid 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