L3 + Chp 3

Question 1

How are microorganisms measured?

Answer 1

micrometers (μm) and nanometers (nm)

Question 2

How many nanometers is 10 μm?

Answer 2

1000nm/1 μm x 10nm = 10,000 nm

Question 3

What is Light microscopy?

Answer 3

uses visible light to observe specimen

Question 4

What are the 6 different types of light microscopy?

Answer 4

• compound light microscopy
• darkfield microscopy
• phase contrast microscopy
• differential interference contrast microscopy
• fluorescence microscopy
• confocal microscopy

Question 5

What is compound light microscopy?

Answer 5

objective lens is magnified bu the ocular lens

Question 6

What is the total magnification of a microscope w/ a 40X objective lends and a 10X ocular lens?

Answer 6

400X

Question 7

What is total magnification regarding compound light microscopy?

Answer 7

objective lens x ocular lens

Question 8

What is resolution regarding compound light microscopy?

Answer 8

the ability of the lenses to distinguish two points

Question 9

do short or long wavelengths of light provide greater resolution?

Answer 9

shorter wave lengths

Question 10

What is refractive index regarding compound light microscopy?

Answer 10

measure of light-bending ability of a medium

Question 11

what is used to keep light from refracting?

Answer 11

immersion oil

Question 12

what is brightfield illumination regarding compound light microscopy?

Answer 12

common type light microscopy
- dark objects visible against bright background
- light reflected off specimen DOES NOT enter objective lens

Question 13

Through what lenses doe slight pass in a compound microscope

Answer 13

condensor, objective, ocular lenses

Question 14

What is Darkfield microscopy?

Answer 14

light objects visible against dark background

Question 15

What is Phase contrast microscopy?

Answer 15

allows examination of living organisms and internal cell structure
brings together two sets of light rays, direct rays, and diffracted rays to form an image

Question 16

What is differential interference contrast microscopy?

Answer 16

uses two light beams and prisms to split light beams = more contrast and color to the specimen

Question 17

What is fluorescence microscopy

Answer 17

uses short wavelength UV light
- absorbs UV light and emit longer wavelength
- cells may be stained w/ fluorescent dyes

Question 18

What is Confocal microscopy

Answer 18

• cells are stained with fluorochrome dyes
• short wavelength (blue) light is used to excite a signle plane of a specimen

Question 19

What is super resolution light microscopy

Answer 19

uses two laser beams
1 stimulates fluorescent molecules to glow
2 cancels out all fluerescence

Question 20

What is electron microscopy

Answer 20

• uses electrons instead of light
• shorter wavelength
• used for images too small to be seen w/ light

Question 21

WHat is scanning electron microscopy

Answer 21

produces a beam of electrons that scans the surface of an entire specimen
- emitted from the specimen produce a 3 dimensional image
- magnifies objects 1,000 to 500,000

Question 22

What is Staining

Answer 22

coloring microorganisms w/ a dye that emphasizes certain structures

Question 23

What is a Smear

Answer 23

thin film of a material containing microorganisms spread over a slide

Question 24

What is a Chromophore

Answer 24

stains consisting of a positive and negative ion, one of which is colored

Question 25

What is a basic dye in staining?

Answer 25

a salt in which the color is in the positive ion; used for bacterial stains

Question 26

What are acidic dyes?

Answer 26

a salt in which the color is in the negative ion; used for negative staining

Question 27

What is negative staining?

Answer 27

coloring the background instead of the cell

Question 28

What is a mordant?

Answer 28

substance added to a staining solution to make it stain more intensely

Question 29

What is a differential stain?

Answer 29

stain that distinguishes objects on the basis of reactions to the staining procedure

Question 30

What is a gram stain?

Answer 30

differential stain that classifies bacteria into two groups, gram positive and gram-negative

Question 31

What are gram-positive bacteria?

Answer 31

bacteria that retain crystal violet color after decolorizing by alcohol; they stain dark purple

Question 32

What are gram-negative bacteria?

Answer 32

bacteria that LOSE the crystal violet color after decolorizing by alcohol; they stain red after treatment w/ safranin

Question 33

What is an Acid fast stain

Answer 33

differential stain used to identify bacteria that are not colorized by acid-alcohol

Question 34

What is acid fast stain used for?

Answer 34

Identification of
- mycobacterium tuberculosis
- nocardia

Question 35

What are special stains?

Answer 35

used to color parts of microorganisms, like endospores, flagella, or capsules

Question 36

What is a capsule? What is a capsule stain?

Answer 36

gelatinous covering composed of a polysaccharide or polypeptide that does not accept most dies.
capsule stain: suspension of india ink or nigrosin that contrasts the background with the capsule, which appears as a halo around the cell

Question 37

What is Endospore spore staining

Answer 37

resistant, dormant structures inside some cells that cannot be stained by ordinary methods

Question 38

What is a Flagella stain

Answer 38

• structures of locomotion
• uses a mordant and carbolfuchsin to thicken appearance of flagella, making them visible under the light microscope

Question 39

How do unstained capsules appear? Stained capsules?

Question 40

What does it mean when a microscope has a resolution of 0.2 nm?