technique de labo

Question 1

Spread-plate method

Answer 1

• pipette
• spread the sample evenly over surface of agar
• Incubation

Question 2

Pour-plate method

Answer 2

• Sample pipette into sterile plate
• Sterile medium added and mixed
• Solidification and incubation

Question 3

What do u need for growth to happen?

Answer 3

permissive growth medium

Question 4

When are results reliable ?

Answer 4

colonie btw 30-300

Question 5

Serial dilution, bacterial culture can reach?

Answer 5

high humbers of cells

Question 6

serial dilution, How to get viable count of such cultures?

Answer 6

serial dilutions have to be made

Question 7

Seria dilution, the resulsts and reproducibility are strongly affected by?

Answer 7

the skills of the technician

Question 8

CFU

Answer 8

number of colonie / dilution x volume plated

Question 9

microscopic counts

Answer 9

use of special slides known as counting chambers

Question 10

microscopic counts, tu dois faire attention a pas

Answer 10

overflow

Question 11

microscopic counts, technique where u can?

Answer 11

count cells, dead , alive, and the one’s who can’t grow in lab

Question 12

What can be used to differentiate dead from alive?

Answer 12

Variability staining

Question 13

microscopic counts, what are the pros?

Answer 13

• Fast

- No need to wait until bacteria has grown (no incubation)

Question 14

microscopic counts, cons?

Answer 14

• Small cells can be missed

- motile cells are hard to count and must be immobilized

Question 15

What happen if a cell is on the line?

Answer 15

u count it but u don’t count the ones who are at the top or at the bottom

Question 16

Flow cymetry

Answer 16

technology that is used to analyse the physical and chemical characteristics of particles in a fluid as it passes through at least one laser.

Question 17

flow cymetry, is better at?

Answer 17

counting big cells

Question 18

Big cells like ?

Answer 18

Protozoan,yeast,mammalian,cells

Question 19

flow cymetry, what allows labeling of specific cell types or species

Answer 19

Detection of fluorescent dyes

Question 20

Flow cymetry, en gros?

Answer 20

a chaque fois que passe une cellule le laser est interrompu et un signal est donner

Question 21

flow cymetry, et quand une cellule par exemple stained passe?

Answer 21

le laser emet deux type de reflection , une reflextion stained et une reflexion normale

Question 22

flow cymetry can be used to sort cells according?

Answer 22

size,shape,labeling

Question 23

cons of Flow cytometry?

Answer 23

can be time consuming and expensive

Question 24

Turbidimetric method

Answer 24

the process of measuring the loss of intensity of transmitted light due to the scattering effect of particles suspended in i

Question 25

turbidity is measured with?

Answer 25

spectrophotometer

Question 26

spectrophotomer?

Answer 26

an instrument that passes light through a cell suspension and measures the unscattered light that emerges

Question 27

A spectrophotometer employs a?

Answer 27

prism or diffraction grating to generate incident light of a specific wavelength (

Question 28

what happens in the spectrophotometer en ordre?

Answer 28

• Light
• Prism ( generate incident light )
• passes filter
• runs through the sample containing cells
• Photocell (measures unscattered light)

Question 29

what is measured is?

Answer 29

the optical density ( log Io/I)

Question 30

turbidity works until &

Answer 30

jusqu’a une certaine concentration

Question 31

specto, measures both contribution of ?

Answer 31

both living and dead cells

Question 32

OD is affected by?

Answer 32

properties of cells: size, clumping

Question 33

If bacterias form aggregates?

Answer 33

can decrease the spectograph measurement

Question 34

spectogram is viable btw ?

Answer 34

90.1 and 1

Question 35

A standard curve must be made
and the relationship between OD
and cell number must be
established?

Answer 35

empirically