Ch 2 Types Of Microscopy & Ex

Question 1

Source of illumination for

bright field

Answer 1

White light

Question 2

Source of illumination for

Darkfield

Answer 2

White light

background is dark image is going to be light

Question 3

Source of illumination for

Phase contrast

Answer 3

White light

Question 4

Source of illumination for

TEM

Answer 4

Electron beams

Question 5

Source of illumination for

SEM

Answer 5

Electron beams

Question 6

Source of illumination for

Fluorescence

Answer 6

UV

Question 7

What does TEM stand for

Answer 7

Transmission Electron Microscopy

Question 8

What does SEM stand for

Answer 8

Scanning electron microscopy

Question 9

Advantages of

Bright field

Answer 9

Can be used for both live unstained material and preserved stained material

Forms it’s image when light is transmitted through the specimen

lightweight

cheap and easy to use about $2500

living cells

Question 10

Disadvantages of

Brightfield

Answer 10

Bacteria must be stained before we observe

Does not allow for us to observe live and interacting cells

poorest resolution 0.2 microns

low contrast: has to have color or have to stain

Question 11

Advantages of

Darkfield

Answer 11

Visualize living cells that would be distorted by drying or heat or that cannot be stained with the usual methods

Cells do not have to be stained

better contrast than brightfield

can see live bacteria that moves like corkscrews

diagnostic tool for certain bacteria (syphilis)

easy to use

living cells

Question 12

Disadvantages of

Darkfield

Answer 12

Cannot see color

Distorts size

surface area can get distorted (glare) (topography)

cannot use for stained stuff because it can lead to more distortion

light can kill or damage sample

Question 13

Advantages of

Phase Contrast

Answer 13

Observing intracellular structures such as bacterial endospores, granules, and organelles, as well as the locomotor structure of eukaryotic cells such as cilia

can see live cells

can kind of see 3D imagery in the sample

about 5k-7k

living cells

Question 14

Disadvantages of

Phase Contrast

Answer 14

Decreased resolution

Thick specimens appear distorted has a halo effect

Question 15

Advantages of

TEM

Answer 15

views detailed structure of cells and viruses (inside)

can reach 100,000x TM

can see inside (intracellular detail)

2.5 nm (resolution

dead cells

Question 16

Disadvantages of

TEM

Answer 16

can see dead speciamens

operation and analysis requires special training

very expensive
$1 million

have to provide the contrast
have to coat the sample with something sometimes gold

always in black and white

coat in heavy metal

inability to view live samples

Question 17

Advantages of

Bright field

Answer 17

Can be used for both live unstained material and preserved stained material

Forms its image when light is transmitted through the specimen

lightweight

cheap and easy to use about $2500

dead cells

Question 18

Advantages of

SEM

Answer 18

creates an extremely detailed 3-dimensional view of all kinds of objects, from plaque on teeth to tapeworm heads

modern SEMs allow for the generation of data in digital form

can see outside (extracelllular detail)

scan the surface

dramatic and realistic images

10,000x TM

resolution: 20 nanometers

can view viruses (outside)

Question 19

Disadvantages of

SEM

Answer 19

limited to solid samples

special training is required

expensive

coat with gold and platinum

hard to access
images in black and white

inability to analyze live specimens

Question 20

Advantages of

Fluorscence

Answer 20

diagnoses infections and pinpointing particular cellular structures

more accurate

better resolution

stain (antibody) to see if what is in the infection on the antigens

good for research

immunology

about $200k

dead cells

Question 21

Disadvantages of

Fluorescence

Answer 21

higher cost

technical complexity

if you do not have a stain it will not be useful

most of the time samples are dead

can use on living samples if they naturally fluorescence

has to be pitch black