Chapter 3

Question 1

a microscope has only one lens

Answer 1

a simple microscope

Question 2

Ocular lens magnify the specimen ______ times.

Answer 2

X10

Question 3

There are _____ objective lenses

Total magnification of a specimen = objective lens  ocular lens

Answer 3

4

Question 4

• scanning magnification

Answer 4

x4

Question 5

• low power

Answer 5

x10

Question 6

• high power

Answer 6

x 40

Question 7

• oil immersion

Answer 7

x100

Question 8

Total magnification of a specimen =

Answer 8

objective lens X ocular lens

Question 9

the ability of the lenses to distinguish two points

Answer 9

resolution

Question 10

_________ wavelengths of light provide greater resolution

Answer 10

shorter

Question 11

Resolution =

Answer 11

wave length (535 nm)  divided by              
 	2 x numerical apperture

Question 12

the light-bending ability of a medium.

Answer 12

refractive index

Question 13

is used to keep light from bending

Answer 13

Immersion oil

Question 14

Glass and immersion oil has the same refractive index.

Answer 14

The light may bend in air so much that it misses the 100 x magnification lens

Question 15

Uses UV light.
Fluorescent substances absorb UV light and emit visible light.
Cells may be stained with fluorescent dyes (fluorochromes).

Answer 15

Fluorescence Microscopy

Question 16

What Uses electrons instead of light.
The shorter wavelength of electrons gives greater resolution.
Light passes through specimen, then an electromagnetic lens, to a screen or film.
Specimens may be stained with heavy metal salts.

Answer 16

Electron Microscopy

Question 17

Transmission Electron Microscopy (TEM)

10,000-100,000; resolution 2.5 nm

Answer 17

`

Question 18

Scanning Electron Microscopy (SEM)

1000-10,000; resolution 20 nm

Answer 18

`

Question 19

A thin film of a solution of microbes on a slide is a ______

Answer 19

smear

Question 20

A smear is usually ______ to attach the microbes to the slide and to kill the microbes.

Answer 20

fixed

Question 21

Stains consist of a _______ & _____ ion

Answer 21

positive & negative

Question 22

In a _____ dye, the chromophore is a cation

Answer 22

basic

Question 23

In an _______ dye, the chromophore is an anion

Answer 23

acidic

Question 24

Bacteria are slightly ______charged at pH 7

Answer 24

negatively

Question 25

More basic dyes are used to stain bacteria, since the cells are _____ charged and the dye has a ______ charged chromophore

Answer 25

negatively charged; positively charged

Question 26

Staining the background instead of the cell is called _________ _________

Answer 26

negative staining

Question 27

_______ dyes are used in negative staining.

Answer 27

acidic

Question 28

__________ charged bacterial cells repel the negatively charged dye staining the background instead of the cells.

Answer 28

negatively

Question 29

Use of a single basic dye is called a _____stain; used to stain any bacteria

Answer 29

simple

Question 30

________ Stains are used to identify different types of bacteria gram stain, acid-fast stain

Answer 30

differential

Question 31

_____ stains/______ stains: use to identify different bacterial structures. ex- capsule stain, endospore stain, flagella stain

Answer 31

special; structural

Question 32

The Gram stain classifies bacteria into gram-_____ and gram-_____.

Answer 32

positive and negative

Question 33

Gram-______ bacteria tend to be killed by penicillin and detergents.

Answer 33

positive

Question 34

Gram-______ bacteria are more resistant to antibiotics.

Answer 34

negative

Question 35

A gram stain includes what 4 things?

Answer 35

includes a primary stain, mordant, decolorizing agent and a secondary or counter stain.

Question 36

A _____is used to hold the stain

Answer 36

mordant

Question 37

gram stains- Primary stain: crystal violet turns what color for Gram + cells and what color for Gram - cells?

Answer 37

+ purple | - purple

Question 38

gram stains- Mordant Iodine turns gram + what color? gram - what color?

Answer 38

+ purple | - purple

Question 39

gram stains- Decolorizing agent: | Alcohol-acetone turns gram + what or

Answer 39

+ purple | -colorless

Question 40

gram stain- Counterstain: | Safranin

Answer 40

+ purple | - red

Question 41

most of the bacterial cultures we use in the lab are ____ cultures. Agar slants are used to grow and maintain ___ cultures. Also, bacterial cells in a ____ culture will have the same shape or morphology

Answer 41

pure

Question 42

This can be a contamination due to bad aseptic technique. Usually, bacterial cells in a ____ culture will have different shapes or morphology

Answer 42

mixed culture

Question 43

Gram stain works better when ____ bacterial cultures (cells that are less than _____ old) are used.

Answer 43

young; 24 hours

Question 44

When gram positive bacterial cells get ____, their peptidoglycan layer in the cell wall start to _____ ____, not being able to retain the primary stain as well as younger cells. These cells can get decolorized and then take the secondary stain in.

Answer 44

old; break down

Question 45

Cells that retain a ____ stain in the presence of acid-alcohol are called acid-fast.

Answer 45

basic

Question 46

______ fast cells lose the basic stain when rinsed with acid-alcohol, and are usually counterstained (with a different color basic stain) to see them.

Answer 46

non-acid

Question 47

acid- fast stain- Primary stain: Carbolfuchsin turns acid- fast cells what color? turns other cells what color?

Answer 47

acid- fast: Dark red other cells: dark red

Question 48

acid- fast stain- Decolorizing agent: Acid-alcohol turns acid- fast cells what color? turns other cells what color?

Answer 48

acid- fast: Dark red other cells: colorless

Question 49

acid- fast stain- Counterstain: Methylene blue turns acid- fast cells what color? turns other cells what color?

Answer 49

acid- fast: Dark red other cells: Blue

Question 50

____ staining and _____ staining is useful for capsules.

Answer 50

negative; simple

Question 51

_____ is required to drive a stain into endospores.

Answer 51

heat

Question 52

_____ staining requires a mordant to make the flagella wide enough to see.

Answer 52

Flagella