labs 6-10

Question 1

simple stain

Answer 1

using only one stain

Question 2

direct stain

Answer 2

uses simple stain and stains cells

Question 3

negative stain

Answer 3

uses simple stain and stains background only

Question 4

beaded

Answer 4

bacteria not stainded evenly so dark spots appear

Question 5

bipolar staining

Answer 5

spots of stain on end of cell

Question 6

basic dyes(direct staining)

Answer 6

postively charged(cation) chromophores colour negative bacterial cells

Question 7

acid dyes(negative staining)

Answer 7

negatively charged (anion) chromophores repelled by negatve bacteria cells so stain positive background

Question 8

smear

Answer 8

thin layer of bacterial cells onto slide and air dry

Question 9

heat fixed

Answer 9

apply heat to smear which shrinks bacteria and helps it stick on if too much then cells wrap

Question 10

vortex

Answer 10

swirling liquid in tube

Question 11

turbidity

Answer 11

cloudiness of broth

Question 12

if light bacterial growth do

Answer 12

8-10 loops

Question 13

if heavy bacterial growth do

Answer 13

4-6 loops

Question 14

differential stain

Answer 14

distinguishes between various microorganisms according to how they take dyes (2dyes)

Question 15

gram stain

Answer 15

type of differential showing gram positive(purple thick peptidoglycan) or negative(pink thin peptidoglycan)

Question 16

primrary dye and counterstain for gram

Answer 16

crystal violet and safrain

Question 17

iodine is what in gram stain

Answer 17

mordant trapping agent that increases cells desire for stain by binding with primary and becoming larger than it insoluble complex

Question 18

what does decolourizer do

Answer 18

it makes pores in cell wall allowing dye to come out for thinner ones pores bigger so comes out faster but in thicker ones the spores are smaller so comes out less

Question 19

3 advantages of negative staining

Answer 19

helps us see bacteria that resist stain, no need for heat fix so do not shrink and see actual size, and can be used on bacteria too delicate for heat fixing

Question 20

capsules

Answer 20

slimy layer around cell that is neutral so does not take in dye using negative allows us to see since glows and counterstaining cells helps see better

Question 21

negative stain example

Answer 21

nigrosin

Question 22

endospore

Answer 22

allows bacteria to survive in poor conditions

Question 23

germination

Answer 23

once environment better bacteria returns to vegtative or growing state

Question 24

endospore staining

Answer 24

resist dye unless heat applied so it can penetrate spore coat

Question 25

schaeffer fulton endopsore stain

Answer 25

uses heat to force primary stain malachite green into spores and water used as decolourizer then counterstained with safrain

Question 26

steps of endospore stain

Answer 26

paper on slide, flood with malachite green, apply heat for 5 mins, cool for 1 min, apply water for 15-30 secs, use safrain wait fro 1 min, then rinse

Question 27

aerotolerance

Answer 27

indicate ability or inability of organism to grow with o2

Question 28

obligate aerobes

Answer 28

bacteria only grow with o2

Question 29

facultative anaerobes

Answer 29

bacteria grow better with o2 but still grow without

Question 30

obligate anaerobes

Answer 30

grow only without o2 cause o2 has two unpaired electrons and makes lots of toxic o2

Question 31

enzymes obligate aerobes have and faculitative

Answer 31

superoxide dismutase and catalase kills compenets made by toxic o2

Question 32

aerotolerant anaerobes

Answer 32

cannot use o2 but not harmed by it

Question 33

microaerophiles

Answer 33

need reduced amount of o2 and increased amount of co2 for growth

Question 34

excluding o2 use

Answer 34

Gas pak anaerobic system with chems that release hydro and co2 when air comes with lid in place they react and form water and removes free o2 with wayer droplets on side methyelene blue indicator turns with no o2 and blue if there is

Question 35

reducing media

Answer 35

contains reagents that chemically combine with free o2 reduces concentration of o2

Question 36

fluid thiol medium contains

Answer 36

sodium thiol(combines o2 to remove from broth), small amount of agat increases viscosity to make it more difficult for air to diffuse, and redox potential indicator to show free o2 turns pink when oxidized and colourless when reduced