Quiz 2

Question 1

Using a microscope adjust the light intensity by moving the______________ until the image has the best _________ against the back ground.

Answer 1

Diaphragm lever, contrast

Question 2

Oil immersion is used on which objective?

Answer 2

100X

Question 3

Should the diaphragm be fully open or fully closed during oil immersion?

Answer 3

Open

Question 4

Always move objective lens and stage towards or away from each other to prevent damage to the lens

Answer 4

Away

Question 5

What is used to clean the oil from the objective?

Answer 5

Lint free Lens paper

Question 6

If the light intensity is too high the ________ between the microbes and the _________ will suffer

Answer 6

Contrast, background

Question 7

As magnification increases the light must ______

Answer 7

increase

Question 8

Can kimwipes be used in the lens?

Answer 8

No

Question 9

Reasons oil immersion lens is not working

Answer 9

Not enough oil, Air bubbles, not enough bacteria, didn’t centre, upside down slide, fine focus turned too far,

Question 10

Why air dry the film?

Answer 10

to prevent washing off during staining, and denature bacterial enzymes that could digest the cell wall.

Question 11

Preparing a smear - Add ___% methanol for ___min

Answer 11

95%, 1

Question 12

thick smear will make it difficult to

Answer 12

observe cell shape, arrangement, and size - thick smears may not be completely decolorized in a differential stain.

Question 13

staining times for 1. carbolfuchsin, 2. crystal violet, 3. methylene blue, 4. safranin in a simple stain?

Answer 13

1. 5-10 sec
2. 20-30 sec
3. at least 1 min
4. at least 1 min

Question 14

gram stain - which stain first for how long

Answer 14

crystal violet for 20 secs

Question 15

gran stain - which stain second for how long

Answer 15

Gram’s iodine - 1 min

Question 16

Gram stain - decolorize with?

Answer 16

95% ethanol or ethanol/acetone

Question 17

gram stain - which stain is 3rd? for how long?

Answer 17

Safranin - 1min

Question 18

if gram’s iodine is pale yellow

Answer 18

it’s old and lost it’s potency

Question 19

if culture used to prepare smear is over 18hours some gram- _____ bacteria will appear gram _______

Answer 19

positive, negative

Question 20

if too much decolorizing agent is applied

Answer 20

too much crystal violet/iodine complex will wash out from gram positive cell walls

Question 21

Why is negative stain beneficial in some cases

Answer 21

some cells are difficult to stain with basic dyes

some cells are fragile and easily distorted by heat-fixation

Question 22

Negative stain - if nigrosin is pushed not pulled the film will not be_______

Answer 22

uniform

Question 23

Preparing a capsule - on top of the fixed nigrosin cover with

Answer 23

safranin or crystal violet

Question 24

Capsule stain is to view

Answer 24

capsules or slime layers

Question 25

What stain can stain an endospore with heat?

Answer 25

Malachite Green

Question 26

Endospores are generated by a few ______ of Gram_______ bacteria

Answer 26

genera, positive

Question 27

the size of a microorganism is measured in

Answer 27

micrometers uM

Question 28

a calibrated ruler on a glass disk is placed in an ocular lens and is called?

Answer 28

Ocular micrometer

Question 29

engraved lines on the a calibrated ruler is _______aprt

Answer 29

10 uM

Question 30

Gram-Positive finishes as what colour

Answer 30

purple

Question 31

Gram-Negative finishes as what colour

Answer 31

safranin