Ch 3

Question 1

metric units

Answer 1

1um=10-6m=10-3mm, 1um=1000nm

Question 2

3 ways to view a specimen

Answer 2

1. brightfield illumination
2. darkfield illumination
3. phase contrast

Question 3

brightfield illumination

Answer 3

dark objects are visible against a bright background, light reflected against a specimen does not enter the objective lens

Question 4

darkfield illumination

Answer 4

light objects are visable against a dark background, light reflected off the specimen enters the objective lens

Question 5

phase-contrast

Answer 5

accentuates diffraction of the light that passes through a specimen

Question 6

acidic dye

Answer 6

chromophore is an anion

Question 7

basic dye

Answer 7

chromophore is a cation

Question 8

list the steps of a gram stain (6)

Answer 8

1. add crystal violet
2. mordant
3. water rinse
4. decolorizing agent
5. safranin counterstain
6. water rinse

Question 9

gram stain reactions- crystal violet

Answer 9

both turn purple

Question 10

gram stain reaction-mordant

Answer 10

both turn purple

Question 11

gram stain reaction- first water rinse

Answer 11

positive-purple, negative clear

Question 12

gram stain reaction- safranin counterstain

Answer 12

pos-purple, neg-red

Question 13

gram stain positive

Answer 13

penicillin will kill, thick cell wall

Question 14

simple stain

Answer 14

use of a single basic dye

Question 15

negative stain

Answer 15

staining the background instead of the cell

Question 16

gram stain- why?

Answer 16

differential stain classifies bacteria into gram pos and neg

Question 17

acid-fast stain

Answer 17

differential stain tells microbacterium- waxy cell wall (TB test)

Question 18

capsule stain

Answer 18

shows if cell has a capsule

Question 19

endospore stain

Answer 19

shows endospores (anthrax)

Question 20

flagella stain

Answer 20

shows flagella

Question 21

gram stain negative

Answer 21

resistant to antibiotics, thin cell wall w peptidoglycan