Lecture 5-7 Microscopy

Question 1

Number of nanometers in a micrometer

Answer 1

1000

Question 1

Average size of bacteria

Answer 1

1-2 micrometers (1000-2000 nanometers)

Question 2

Unit of size for viruses

Answer 2

nanometers

Question 3

Number of micrometers in a milimeter

Answer 3

1000

Question 4

Number of lenses a simple microscope has

Answer 4

1

Question 5

What a light microscope uses to observe things

Answer 5

light

Question 6

Number of lenses a compound microscope uses

Answer 6

2

Question 7

Type of light microscope most commonly used in labs

Answer 7

brightfield microscopy

Question 8

Purpose of ocular lens

Answer 8

the eyepiece; remagnifies image (10x, 20x)

Question 9

Purpose of objective lens

Answer 9

primary lens that magnifies the specimen (1x - 100x)

Question 10

Purpose of the stage

Answer 10

holds microscope slide in position

Question 11

Purpose of condesner

Answer 11

focuses light through specimen

Question 12

Purpose of diaphragm

Answer 12

controls the amount of light entering condenser

Question 13

Purpose of illuminator

Answer 13

the light source

Question 14

Total magnification =

Answer 14

objective lens x ocular lens

Question 15

Resolution

Answer 15

ability to distinguish between two adjacent objects; very very important

Question 16

Resolution of compound light microscope

Answer 16

0.2 micrometers

Question 17

Shorter wavelengths of light =

Answer 17

greater resolution

Question 18

Refraction

Answer 18

bending of light through different substances

Question 19

Need immersion oil when

Answer 19

using a magnification above 100x

Question 20

Purpose of immersion oild

Answer 20

helps capture beam of light and prevents it from bending off

Question 21

Bright field microscopy is best for

Answer 21

fixed, stained specimens

Question 22

Dark field microscopy is best for

Answer 22

unstained, live specimens

Question 23

Phase contrast is best for

Answer 23

unstained, live, and moving specimens

Question 24

Fluorescence Microscopy

Answer 24

using UV light to visualize locations and patterns, specimen is dead

Question 25

Confocal Microscopy

Answer 25

using multiple images all put together, gives 3D image

Question 26

Purpose of contrast

Answer 26

provides a better final image through staining

Question 27

Dyes

Answer 27

organic compounds that bind to specific cellular materials; usually basic/cationic to bind with negatively charged cell components

Question 28

3 types of stains

Answer 28

simple, differential, special

Question 29

Simple stain

Answer 29

use of a single basic dye; used to visualize cell structure and arrangement

Question 30

Differential stain

Answer 30

separates bacteria into groups

Question 31

2 types of differential stains

Answer 31

gram and acid fast stains

Question 32

Purpose of a gram stain

Answer 32

classify bacteria as either Gram-positive or Gram-negative

Question 33

Bacteria easily killed by antibiotics

Answer 33

Gram-positive

Question 34

Bacteria more resistant to antibiotics

Answer 34

Gram-negative

Question 35

Bacteria that appear blue/purple after gram stain

Answer 35

Gram-positive

Question 36

Bacteria that appear red/pink after gram stain

Answer 36

Gram-negative

Question 37

Downside of gram staining

Answer 37

kills bacteria cells

Question 38

Purpose of acid-fast stain

Answer 38

identifies bacteria that have a waxy cell wall (ex. Mycobacteria & Nocardia)

Question 39

Mycolic acid

Answer 39

waxy lipid material that makes up waxy cell walls

Question 40

Color of acid-fast stains

Answer 40

red

Question 41

Purpose of special stains

Answer 41

to stain special structures

Question 42

Stain for flagella

Answer 42

carbol fuschin

Question 43

Stain for capsules

Answer 43

colloids

Question 44

Stain for endospores

Answer 44

malachite green

Question 45

What electron microscopes use

Answer 45

electron beams

Question 46

Resolution of an electron microscope (TEM)

Answer 46

0.2 nanometers

Question 47

2 types of electron microscopes

Answer 47

transmission electron microscope, scanning electron microscopy

Question 48

Purpose of TEM

Answer 48

images internal structures of cell, need thin slices of the specimen

Question 49

Purpose of SEM

Answer 49

provides 3D image-surface of cell

Question 50

Negative staining

Answer 50

stain used in electron microscopy to reveal the texture of the outside of cells, viruses, and isolate sub cellular organelles

Question 51

Resolution of electron microscope (SEM)

Answer 51

20 nm