quiz 7

Question 1

What is the morphology of enterobacteria?

Answer 1

facultativ anaerobes, gram negative rods, oxidase negative, motile

Question 2

What are the key distinguishing factor of coliforms?

Answer 2

Ferment glucose to produce acid and gas

Question 3

How do we select for enterobacteria?

Answer 3

in tube: fill with broth so that the lower regions turn anaerobic
on plate: incubate aerobically to kill off other anaerobic gut bacteria

Question 4

What is special about EMB agar?

Answer 4

selective and differential, dyes inhibit growth of gram + and g- cocci, has lactose indicator

Question 5

what is the indole test?

Answer 5

measures ability for organism to break down amino acid tryptophan using tryptophanase2

Question 6

What is the physical appearance of E.coli on EMB agar?

Answer 6

irregular, flat, almost black colonies with green sheen

Question 7

Why use the lactose mineral salt?

Answer 7

To restrict streptococcus and micrococcus

Question 8

What is quorum regulation?

Answer 8

population density dependent gene regulation

Question 9

What is casein? Where is it present?

Answer 9

Casein is a substrate that is hydrolyzed by caseinase, its present in milk

Question 10

What encodes for caseinase in psedumonads?

Answer 10

AHL reception

Question 11

How will we know if caseinase is quorum regulated?

Answer 11

If we have growth in the higher population density only

Question 12

What is a positive caseinase test?

Answer 12

Clear colonies

Question 13

How will we know if there’s no caseinase present?

Answer 13

Pseuds will grow in casamino acids but not in casein

Question 14

What do luminsecent bacteria require to reproduce?

Answer 14

organic substrate, e- acceptor and donor, luciferase

Question 15

Where are luminescent bacteria present?

Answer 15

In photo bacterium and vibrio

Question 16

What is the gram morphology and classification of luminescent bacteria?

Answer 16

gram negative facultative anaerobes with flagella

Question 17

What is a saprophyte?

Answer 17

A bacteria that can live on organic bacteria

Question 18

What is luciferase?

Answer 18

a very energy costly enzyme that catalyzes the light rxn to produce luminescence

Question 19

How do conidia appear under gram stain?

Answer 19

gram positive spheres or ovals

Question 20

What are sporophores?

Answer 20

conidia bearing hyphae of a colony

Question 21

Which antibiotic will actinomycetes produce?

Answer 21

sterptomyces

Question 22

How do we know if our actinomycete produces antibiotics?

Answer 22

It will diffuse into the media

Question 23

What is the purpose of SWC media with agar degraders?

Answer 23

it is a rich media that will be used to see if our bacteria has exoenzyme production?

Question 24

What is the purpose of ASN+glu with agar degraders?

Answer 24

catabolite repression, how affects agarase expression

Question 25

What is the purpose of ASN media with agar degraders

Answer 25

normal control plate

Question 26

What is a hyphae?

Answer 26

Individual filaments of actinomycetes that grow into a mycelium

Question 27

What kind of metabolism do actinomycetes do?

Answer 27

chemoheterotrophs that can degrade recalcitrant polymers

Question 28

What happens when the center of an actinomycete colony becomes nutrient starved?

Answer 28

hyphae grow vertically away from substrate to form aerial hyphae. Individual cells of aerial hyphae is conidia. Hyphal structure with conidia is sporophore

Question 29

What organic compound do actinomycetes produce?

Answer 29

polycyclic carbs called geosmins, which give off earthy smell of soil