Tools of the Labratory

Question 1

inoculation

Answer 1

introducing microbes to a fresh medium

Question 2

incubation

Answer 2

placing microbes into optimal conditions (temperature, pressure, humidity)

Question 3

what is the significance of 37C?

Answer 3

reflects body temperature; culture human pathogens/microbes

Question 4

isolation

Answer 4

separating species form the rest of the sample

Question 5

purpose of isolation techniques

Answer 5

achieve/obtain a single colony growing on a solid medium

Question 6

single colony

Answer 6

spot on a plate; single clump of microbes that are clones of each other

Question 7

Fanny Eilshemius Hesse

Answer 7

recommended the use of agar when studying microbes

Question 8

streaking for singles

Answer 8

sectioning areas of microbes and reducing the amount of colonies to make single colonies

Question 9

loop dilution

Answer 9

get sample (liquid/solid), collect on loop, and put into first culture onto sterile warm liquid agar → then placed into petri plate

Question 10

loop dilution characteristics

Answer 10

• microbes embedded into agar (good for anaerobic microbes)
• can be diluted in agar solutions to single out colonies

Question 11

spread plate

Answer 11

uses petri plates (liquid sample); spread culture evenly on plate and can be diluted in multiple tests

Question 12

colony forming unit (CFU)

Answer 12

roughly equivalent to a cell; assume that one colony = one cell

Question 13

broth v agar medium

Answer 13

broth: liquid
agar: solid

Question 14

general-purpose media

Answer 14

medium which will grow most microbes; usually non-synthetic

Question 15

synthetic medium

Answer 15

every molecule and the composition of the media is known

Question 16

enriched media

Answer 16

any type of medium which is used for fastidious microbes (picky microbes)

Question 17

selective media

Answer 17

overlaps with synthetic, some microbes are allowed to grow and divide while other are inhibited from growth

Question 18

differential media

Answer 18

grows everything but shows the difference between each of the microbes
- Carry different characteristics under the media (colors, spread, etc)

Question 19

pure culture

Answer 19

one known species of microbe

Question 20

mixed culture

Answer 20

two microbes which are distinguishable from each other growing on the same media

Question 21

contamination

Answer 21

growth of a microbe which is unwanted

Question 22

viable but not culturable (VBNC)

Answer 22

living microbes that will not grow in the lab
- makes up for 90% of microbes

Question 23

compound microscope

Answer 23

combines 2 different magnifying lenses/curved glasses

Question 24

objective lens

Answer 24

where the light on a microscope passes through

Question 25

ocular lens/eyepiece lens

Answer 25

increases magnification; where you view image

Question 26

condenser lens

Answer 26

focuses the light source onto the specimen; underneath specimen, above the lamp

Question 27

magnification

Answer 27

result of light waves passing through curved glasses/lenses which then refracts light increasing the image of the organisms that you are viewing

Question 28

increasing the curvature of the lens...

Answer 28

increases the magnification

Question 29

resolution

Answer 29

the ABILITY to see two objects as being separate

Question 30

what is the physical limiting factor the keeps light microscopes from visualizing smaller objects?

Answer 30

resolution; harder to obtain smaller wavelengths which is optimal for better resolution of an object

Question 31

limit of resolution

Answer 31

the DISTANCE two objects need to be to be seen as separate

Question 32

how to calculate limit of resolution?

Answer 32

wavelength of light (nm) / NA condenser + NA of objective lens

Question 33

NA

Answer 33

numerical aperture of lens; 200 µm

Question 34

what is the oil immersion lens used for?

Answer 34

to view smaller bacteria and cells

Question 35

what is the purpose of the oil with the 100x lens?

Answer 35

the oil bends/refracts light that would escape to go into the objective lens; retains more of the light moving through the specimen

Question 36

properties of the oil

Answer 36

the oil must have the same refractive properties of glass

Question 37

bright field microscope

Answer 37

most commonly used to view dead cells; field is brighter than the specimen

Question 38

dark field microscope

Answer 38

used to see living specimens (possibly swimming around); field is darker than the specimen

Question 39

what does the dark field microscope highlight?

Answer 39

shines only the exterior of the cell and their general characteristics; does not include the internal structures of the cell

Question 40

use of differential interference contrast (DIC) & phase-contrast microscope

Answer 40

view internal structures of living cells

Question 41

difference between DIC and phase-contrast microscope

Answer 41

each have the ability to view different structures in a cell; use depends on what structure of the cell you are trying to view

Question 42

hanging drop slide

Answer 42

good for large moving organisms

Question 43

electron microscope

Answer 43

electrons go through magnets to increase the size of the image instead of the lens

Question 44

what stain is used for electron microscopes?

Answer 44

specimen is coated in metal particles due to the electrons being able to move through metal easier

Question 45

what do electron microscopes use to help visualize a specimen?

Answer 45

electrons go through magnets to increase the size of the image

Question 46

TEM

Answer 46

transfer electrons through the specimen; electrons come from underneath and through to view internal structure of the cell - specimen must be cut in half

Question 47

SEM

Answer 47

electrons go on top on the surface and they bound off of the microbe to visualize the surface of the cells; scanning over the surface of the cell

Question 48

when are SEM and TEM used?

Answer 48

only used for research

Question 49

Which microscope does not use light in forming the specimen image?

Answer 49

electron microscope

Question 50

Which of the following characteristics refers to the microscope's ability to show two separate entities as separate and distinct?

Answer 50

resolving power

Question 51

A medium is designed that allows only staphylococci to grow. In addition, S. aureus colonies have a yellow halo around them and other staphylococci appear white. This type of media is…

Answer 51

both selective and differential

Question 52

A common medium used for growing fastidious bacteria is...

Answer 52

chocolate agar

Question 53

The Gram stain, acid-fast stain, and endospore stain are...

Answer 53

differential stains

Question 54

Which method often results in colonies developing down throughout the agar and some colonies on the surface?

Answer 54

pour plate

Question 55

Which microscope shows cells against a bright background and the intracellular structures of unstained cells based on their varying densities?

Answer 55

phase contrast

Question 56

If a microbiologist is studying a specimen at a total magnification of 950X, what is the magnifying power of the objective lens if the ocular lens is 10X?

Answer 56

95X

Question 57

A nutrient medium that has all of its chemical components identified and their precise concentrations known and reproducible would be termed

Answer 57

synthetic