L7

Question 1

whats the purpose of a candle in a jar?

Answer 1

creates a low oxygen environment

Question 2

what does a candle in a jar do regarding the gases

Answer 2

it reduces CO2 but will not fully remove O2 because candle will burn out before all O2 is used up

Question 3

whats a pro to using a broth media?
con?

Answer 3

grow small to large quantities of culture

contamination AND growth causes cloudiness - not sure what is contaminating or what is growing because it all gets cloudy

Question 4

whats a pro to using a plate media?
con?

Answer 4

easy to store - easy to see what happens to the plate

they are thin and not good for a long term - the nutrients on the media get used up fast

Question 5

whats a pro to using a slant media (same media as plate)?
con?

Answer 5

provides more surface area than a regular tube

cannot isolate bacteria

Question 6

whats a pro to using a semi solid deep media?
con?

Answer 6

bacteria can migrate from point of inoculation - look for motility

difficult to check for purity

Question 7

where does Agar come from?

Answer 7

red algae

Question 8

why didn’t gelatin plates work

Answer 8

they melted at too low temperatures and bacteria could digest them

Question 9

when does Agar plate melt

Answer 9

85 degrees

Question 10

is the basic plate (nutrient agar) selective

Answer 10

no

Question 11

what is a nutrient agar suitable for

Answer 11

non-fastidious organsims
(non picky eaters)

Question 12

what is a fastidious organisms

Answer 12

requires complex or particular nutrients to culture

Question 13

what is a selective media

Answer 13

encourages the growth of some bacteria while preventing the growth of others

Question 14

what is differential media

Answer 14

provides different visual cues as to the type of organism growing

Question 15

what is required for a differential media to be successful

Answer 15

growth to differentiate the different bacteria

Question 16

whats an enriched media

Answer 16

allows particular species to grow better
ie. rare bacteria to show up in a mixed bacteria

Question 17

what kind of plate is macConkey Agar

Answer 17

selective and differential

Question 18

what do macConkey Agar plates select against

Answer 18

non enteric gram positives

Question 19

what does a macConkey Agar plate contain

Answer 19

lactose and pH indicators

Question 20

what does the pH indicator do in macConkey Agar

Answer 20

gives it the pink/purple
gives the indicator of lactose fermentation

Question 21

whats a lactose positive result of macConkey Agar plate

Answer 21

pink/purple

Question 22

what colour do fermenters turn in macConkey Agar plate

Answer 22

purple

Question 23

what grows on a macConkey Agar plate

Answer 23

gram (-)

Question 24

what kind of plate is a Mannitol Salt Agar

Answer 24

selective and differential

Question 25

what is a Mannitol Salt Agar made of?

Answer 25

Mannitol salt (favours halophiles)

Question 26

what does a fermenter turn on a Mannitol Salt Agar plate

Answer 26

yellow

Question 27

what colour is a Mannitol Salt Agar

Answer 27

red

Question 28

what is a Mannitol Salt Agar plate useful for detecting

Answer 28

staphylococcus aureus

Question 29

what kind of plate is a blood agar plate

Answer 29

enrichment and differential

Question 30

what is a blood agar plate made of

Answer 30

sheep blood

Question 31

what is an alpha hemolysis

Answer 31

discolouration in or under the colony by bacteria that release H2O2 reducing Fe

Question 32

what is beta hemolysis

Answer 32

clearing due to lysis of RBCs by bacterial enzymes

Question 33

what is gamma hemolysis

Answer 33

no change

Question 34

what plate tests for hemolysis

Answer 34

blood agar plate

Question 35

what plate is not good for bacteria

Answer 35

Saboraud Dextrose Agar

Question 36

what does a Saboraud Dextrose Agar plate contain

Answer 36

same as nutrient age but high amount of glucose

Question 37

whats the pH of Saboraud Dextrose Agar

Answer 37

5.6

Question 38

what does the sugar and acidic pH select for in Saboraud Dextrose Agar plates

Answer 38

yeasts and molds

Question 39

what kind of diagnostic tube is a SIM deep

Answer 39

differential x3

Question 40

what 3 things does SIM deep test for

Answer 40

sulfur reduction indole production motility

Question 41

how to test for sulfur reduction in SIM deep tube

Answer 41

if H2S is produced it will react with ammonium iron II sulphate and turn black

Question 42

how do test for indole production in SIM deep tube

Answer 42

by dripping kovaks reagent on top after incubation if it turns red, it is positive for tryptophan

Question 43

how to determine motility in a SIM deep tube

Answer 43

if cells grow away from the stab the cells are motile

Question 44

whats the point of testing for indole in SIM deep tube

Answer 44

looking for a particular enzyme (tryptophan)

Question 45

is the oxidase test a media?

Answer 45

no

Question 46

what kind of infection does an armadillo carry

Answer 46

M. leprae

Question 47

humans and ____________ carry M. leprae infections

Answer 47

armadillos

Question 48

what is the oxidase test

Answer 48

add a complex reagent that if it reacts it tests for cytochrome 3 oxidase (purple = positive)

Question 49

what is the biochemical identification system

Answer 49

doing several tests at once and then looking up scores in a booklet for species

Question 50

what are 2 additional identification methods

Answer 50

DNA testing Antibody testing

Question 51

hoe long is mycobacterium leprae growth time

Answer 51

12-14 days

Question 52

how fast can E coli divide

Answer 52

20 min

Question 53

what is e coli weight

Answer 53

1 x 10^-12

Question 54

why do we need to use a logarithmic graph when measuring bacteria growth

Answer 54

exponential growth of bacteria

Question 55

will a cuvette get more cloudy as a bacteria growth occurs

Answer 55

yes

Question 56

whats the appropriate amount of colonies to do dilution calculations with

Answer 56

25-250

Question 57

what does a counting chamber count

Answer 57

cells but not live cells

Question 58

whats the BEST number to get on a plate for cell count

Answer 58

100

Question 59

why is 25-250 the good cell range?

Answer 59

because at both extremes the error is the same (equal accuracy)