Microbiology Lab #3

Front 1

each yeast organism is composed of how many eukaryotic cells?

Back 1

one, they are unicellular

Front 2

what shape are yeast cells/

Back 2

oval/spherical

Front 3

yeasts are how many times larger than bacteria?

Back 3

5-10 times larger

Front 4

yeasts produce asexually by a process called what?

Back 4

budding (parent cell is a bud)

Front 5

yeast can also reproduce sexually. the sexual spores are called what?

Back 5

ascospores

Front 6

the medium used to grow yeast and molds is called what?

Back 6

sabouraud dextrose ogar

Front 7

sabouraud dextrose ogar contains lots of _______ and ______

Back 7

glucose and peptone

Front 8

yeasts are ________ anaerobic

Back 8

faculatively

Front 9

with oxygen yeasts use carbs to break down into carbon dioxide and ____

Back 9

water

Front 10

without oxygen yeasts use carbs to break down into carbon dioxide and ____

Back 10

ethanol

Front 11

yeasts have beneficial uses such as what?

Back 11

making bread and alcohol fermentation

Front 12

the scientific name of the type of yeast we looked at in lab is called ________ ___________

Back 12

saccharomyces cerevisiae

Front 13

molds are multicellular and ________ fungi

Back 13

filamentous

Front 14

the macroscopic aggregation of mold cells is called a _____

Back 14

thallus

Front 15

the thallus contains long filaments of cells joined together which are called _______

Back 15

mycelium

Front 16

each strand of mycelium is called a ____

Back 16

hypha

Front 17

there are 3 types of hyphae called what/

Back 17

vegetative, reproductive and rhizoidae

Front 18

what are vegetative hyphae?

Back 18

hyphae grow on the surface of culture media

Front 19

reproductive hyphae grows where?

Back 19

grows upwards and bear the asexual reproductive spores

Front 20

rhizoidal hyphae grows where?

Back 20

below the surface of the culture media and help anchor the mold in place

Front 21

if the hyphae have crosswalls, the crosswalls are called ______

Back 21

septums

Front 22

if there are septums (crosswalls) in the hyphae the hyphae is said to be _______

Back 22

septate hyphae

Front 23

if the hyphae have no crosswalls then the hyphae is referred to as ______

Back 23

eoenocytic hyphae

Front 24

hyphae grow by elongation at the ________

Back 24

tip

Front 25

five of the asexual spores are called what?

Back 25

athropsores, chlamydospores, sporangispores, conidiospores and blastospores

Front 26

3 types of sexual spores?

Back 26

zygospore, ascospore, basidiospore

Front 27

what type of mold was rhizpus on the sabourand dextrose agar medium?

Back 27

sporangiospores

Front 28

What is the difference between vegetative and aerial mycelia?

Back 28

Vegetative Mycelia does not give rise to spores.
Aerial mycelia gives rise to spores.

Vegatiative is the part that is actually in 'physical' contact with whatever the fungi (us) is feeding on. It is the part that 'anchors' and absorbs nutrients. Aerial is the part that produces ASEXUAL spores

Front 29

can bacteriological media be used for the cultivation of molds?

Back 29

yes sabouraud agar us a solid growth medium used for cultivation of fungi

Front 30

in the common bread-mold life cycle, what do the plus and minus signs mean

Back 30

different strains

Front 31

why arent molds streaked for isolation?

Back 31

molds do not produce distinguishable individual colonies the way bacteria do. They produce masses of hyphae called mycelia.

Front 32

are rhizopus hyphae coencytic or septic?

Back 32

nonseptate coenocytic

Front 33

describe the fruiting body of the mold aspergillus niger

Back 33

conidiospores: numerous short lengths of narrow hyphae with short chains of spores

Front 34

describe the fruiting body of penicillium

Back 34

conidiospore

Front 35

why are yeast colonies bigger than bacterial colonies?

Back 35

Yeasts reproduce by budding -- the cell wall projects outward to form a new daughter cell that eventually pinches off from the mother cell. Some may not separate entirely while budding, forming chains of unseparated yeast cells

Front 36

why do yeasts generally have to be cultured for longer periods of time than bacteria?

Back 36

They can be harder to detect and harder to control than bacteria

Front 37

why is sabouraud dextrose agar used to cultivate yeasts?

Back 37

it uses peptone as its protein and dextrose as the carbohydrate for nourishment. bacterial suppression occurs due to the low pH

Front 38

what are coliforms?

Back 38

rod-shaped Gram-negative non-spore forming organisms that ferment lactose with the production of acid and gas when incubated at 35° within 48 hours

Front 39

coliforms are ________ anaerobic

Back 39

faculatively

Front 40

why are coliforms selected as the indicator of water potability?

Back 40

coliforms survive in water and can detect feces. if they are present that means poo is in the water

Front 41

does a positive presumative test indicate that water is potable?

Back 41

if gas is in the tube then water is not potable

Front 42

why is the MPN test qualitative and not quantitative?

Back 42

we arent counting individual bacteria, only guessing

Front 43

what is the function of lactose broth in the MPN test

Back 43

it ferments lactose with gas formation within 48 hours

Front 44

what is the function of levines EMB or LES endo agar in the MPN test

Back 44

used to indidate if coliforms are present. it will show a metallic green

Front 45

what is the function of the tsa slant in the MPN test

Back 45

used to do the gram stain

Front 46

what is the function of gram stain in the MPN test

Back 46

used for looking for negative rods

Front 47

what does a metallic green sheen indicate on an EMB plate?

Back 47

coliforms are present

Front 48

name some bacterial diseases that can be transmitted by polluted water and what causes them

Back 48

shigella- dysentary
salmonella typhi- typhoid fever
e.coli- diarrhea, urinary tract infection
proteus-urinary tract infection
pseudomonas- ear infections

Front 49

how can coliforms in water be detected?

Back 49

by a statistical estimation called the most probable number test

Front 50

the MPN test is divided into 3 parts. Name them

Back 50

presumptive, confirmed and completed tests

Front 51

in the MPN test, what happens in the presumptive test/

Back 51

dilutions from the water sample are added to lactose. after 24 hours one looks for bacteria capable of fermenting lactose with gas production (coliforms)

Front 52

in the MPN test, what happens in the confirmed test?

Back 52

one transfers materials from the highest dilution of the lactose broth tubes that showed gas production into brilliant green lactose bile broth

Front 53

in the MPN test, what happens in the completed test?

Back 53

a sample from the positive brilliant green lactose bile broth is streaked onto a levines EMB. coliforms of the plate are then inoculated into a brilliant green broth and onto a nutrient agar slant

Front 54

On levines EMB plates what happens to coliforms?

Back 54

coliforms produce small colonies with dark centers

Front 55

in the completed test, the end result involves what?>

Back 55

a gram negative non sporing isolated bacterium.

Front 56

in the confirmed test of the MPN test, the formation of any gas at any time indicates what?

Back 56

a positive confirmed test

Front 57

what is a complete virus particle?

Back 57

virion

Front 58

bacteriophages grow and reproduce within _____

Back 58

bacteria

Front 59

one would expect to find bacteriophages when a large group of ______ is present

Back 59

bacteria

Front 60

because the concentration of bacteriophages specific for a particular host may be relatively low, the first step in the isolation procedure is an _______

Back 60

enrichment step

Front 61

when the sample is incubated with a population of the proper host, phages specific for that bacterium will ____________ in number

Back 61

multiply greatly

Front 62

phages are easier to isolate when they are present in _____ numbers

Back 62

greater

Front 63

membrane filtration serves to remove ______ and most __________

Back 63

cell debris and most bacteria

Front 64

any bacteria left over from membrane filtration can be killed and lysed by ________

Back 64

chloroform

Front 65

what is the double layered culture technique?

Back 65

indivdual viruses are isolated by mixing a small amount of filtrate with a young culture of the host bacterium and then spreadng the mixture out on the surface of a petri plate with the nutrient agar

Front 66

in practice, the viruses and bacteria are mixed with a dilute agar medium which is the ___ agar and then poured in a thin layer of the surface of the ___ agar

Back 66

top, base

Front 67

when the top agar of the double layered culture hardens then the bacteria are _______

Back 67

immobilized

Front 68

whenever a virus particle is present in th agar, it will infect an adjacent bacterial cell, reproduce and _____ its host cell

Back 68

lyse

Front 69

what is a clear area of lysed bacteria called?

Back 69

plaque

Front 70

ideally, each virus will produce _____ plaque

Back 70

one

Front 71

what is meant by a plaque-forming unit?

Back 71

one virus that infects a bacterial cell

Front 72

what are coliphages?

Back 72

viruses that infect E.coli

Front 73

determine the number of plaque forming units per ml in a sample that has been diluted 10^-8 and has give 200 plaque forming units when .5ml is placed.

Back 73

200/10^-8

200x 10^8 in .5 ml

times by 2 to get the full 1 ml

400x10^8 in 1 ml.
so the end product is
4.0x 10^10 in 1 ml

Front 74

what effect does chloroform have on viruses? on bacteria?

Back 74

no effect on virus. they could care less

on bacteria, chloroform can lyse the cell membranes

Front 75

bacteriophage are in the t ___ family

Back 75

even

Front 76

what are t4

Back 76

T4 is a bacteriophage that infects E. coli bacteria. Its DNA has an icosahedral head with protein and dna in he center and has 6 tails

Front 77

what is a coliphage?

Back 77

a type of bacteriophage that infects Escherichia coli

Front 78

what are capsids?

Back 78

the protein shell of a virus