Lab Practical Two

Front 1

psychorophile

Back 1

less than 15 detgees celcius

Front 2

mesophile

Back 2

grows between 20 and 45 degrees celcius

Front 3

S, aureus is a

Back 3

mesophile

Front 4

limitations of boiling water for sterilization

Back 4

endospores and thermoduric species will not be killed by boiling water

Front 5

what has the widest range of temperature tolerance

Back 5

spores and bacillus species

Front 6

least tolerant to higher temperatures

Back 6

Pseudomonas aeruginosa

Front 7

thermoduric bacteria

Back 7

bacteria that survives boiling but does not grow

Front 8

what are buffers used for in culture media

Back 8

to neutralize alkaline or acidic metabolites produced during growth

Front 9

why do microbes differ in their pH requirements

Back 9

enzymes required for metabolism and growtj may have different pH optima for different microbes

Front 10

what inhibits microbial growth at nonoptimal pHs

Back 10

enzymes will function at rates lower than their potential at optimal pH

Front 11

What is the pH tolerance of bacteria compared to yeasts?

Back 11

yeasts grow better at higher hydrogen ion concentrations (lower pH) than bacteria

Front 12

yeasts grow

Back 12

at a lower pH than bacteria

Front 13

buffer systems used in microbial media

Back 13

peptide buffers, phosphate buffers, and bicarbonate buffers

Front 14

define a buffer

Back 14

a combinatin of chemical compounds that rsist pH change since they will neutralize Hydrogen and hydroxide and maintain a constant pH

Front 15

simply define a buffer

Back 15

one that maintains a constant pH

Front 16

how do microorganisms change the pH of their own enviorment

Back 16

they produce biproducts that change the pH

Front 17

isotonic solutions

Back 17

have equal concentrations of solute inside and outside the cells

Front 18

hypotonic soultions

Back 18

have a higer concentration of solute inside the cell than outside the cell

Front 19

hypertonic solutions

Back 19

soultions have a higher concentration of solute outside of the cell than inside the cell

Front 20

osmosis

Back 20

the movement of water acrosse a semipermeable membreane in response to differing soulte concentrations on each side.

Front 21

osmotic pressure

Back 21

the force developed within a cell due to movement of water across the cell membrane due to unequal solute concentrations

Front 22

plasmolysis

Back 22

when the plasma membrane shrinks away from a cell wall due to a hypertonic solution

Front 23

halophilic

Back 23

bacteria that tolerate and grow well in hypertonic salt solutions

Front 24

how is it possible for bacteria to grow in a hypertonic enviorment

Back 24

bacteria have membrane structures that can resist plasmolysis and restrict water flow from the cell at high salt cocentrations

Front 25

What concentrations of NaCl are omptimal for most bacteria

Back 25

at or below seatwater, between .5-,85%

Front 26

H.salinarium

Back 26

can tolerate high salt concentrations (halophilic)

Front 27

foods high in salt

Back 27

bacon ham olives canned meat pickles

Front 28

why dont bacteria lyse when placed in a hypotonic solution

Back 28

they have a rigid cell wall that restricts membrane expansion and prevents lysis

Front 29

what are limitations of a test such as the one performed on the evaluation of a disinfectant

Back 29

evaporation, dilution in the natural enviorment and also inactivation of the disinfectant

Front 30

a good infectant is one that

Back 30

easily and quickly diluted and applied, kills all microbes in a short period of time, is inexpensive, and is safe under normal use conditions

Front 31

what is the phenol coefficent technique

Back 31

comparison of a disinfectant with a standard phenol solution that kills all the microorganisms under study within 10 minutes but not within 5 minutes

Front 32

disinfectants that are more effective than phenol have a coefficent

Back 32

coeffiecent greater than 1

Front 33

disinfectants that are less effective than phenol have

Back 33

a coefficent less than one

Front 34

how to determine phenol coeffcient

Back 34

the concentration of the dilution of disinfectant is divived by the concentration of dilution of phenol

Front 35

microbicidial

Back 35

referes to killing of microorganisms

Front 36

microbiostatic

Back 36

refers to inhibiotn of growth of microorganims

Front 37

factors that influence the activity of a disinfectant

Back 37

temperature, pH and humidity

Front 38

why do microorganisms differ in their response to disinfecrants

Back 38

the strucutre of the cell wall may differ resulting in variabl eeffects

Front 39

how can you determine whether the zone of inhibition is due to death or inhibition of bacterium

Back 39

you could subculutre from the zone of no grwoth into the fresh media and see if any microbes grow from it

Front 40

what factors must be carefully controlled in the kirby-bauer method

Back 40

amount of bacteria inoculated, distribution of inoculum, incubation period, antibiotic diffusion rate, concnetration of antibiotic, and growth rate of bacteria

Front 41

in which phase is bacterium most sensitie to an antibiotic

Back 41

early exponential phase cultures are most sensitive

Front 42

if the clinical laboratory reports bacterial susceptibility to an antibiotic but the patient is not responding to it what could be wrong?

Back 42

clerical error, contamination, or the wrong culture could have been tested

Front 43

what are the similarites and difference in response to plates with gram-positive bacteria and gram-negative bacteria,

Back 43

different zones of inhibition indicate effectiviness for the same antibiotics, the diameter of the zone is different, a different series of antibiotics is tested against each group of microbes

Front 44

what is the difference between an antibiotic and and antimicrobic

Back 44

an antibiotic is produced by a microorganism and is effective agains microorganisms and an antimicrobic is a naturally occuring or man made chemical agent effective against microorganisms

Front 45

why are bacteria becoming more resistants to antibiotics

Back 45

the more they are used the more probability to become resistant, use of orally antibiotics that make contact with common organisms in the difestive tract can produce resustant strains, use of antibiotics in animal feeds for commerical animals for food

Front 46

Why are coliforms selected as the indicator of water potability?

Back 46

They indicate the presence of lactose-fermenting gram negative rods. If they are present, the water may contain fecal microbes. and is not potable

Front 47

Does a positive presumptive test indicate the water is potable?

Back 47

not it suggests the water is not potable

Front 48

Why is the MPS test qualitative rather than quantitative

Back 48

It estimates the probable number of microorganisms in 100ml of water without actually counting them.

Front 49

function of lactose broth in the MPN test

Back 49

presumptive indication of coliforms

Front 50

Function of Levines EMD or LES Endo agar

Back 50

used for the completed test indicating the presence of coliforms

Front 51

nutrient agar slant function in MPN

Back 51

used for gram staining the culutre to determine the presence of gram negative rods

Front 52

gram stain

Back 52

shows whether the organisms present in the presumptive and confirmed tests are really gram negative rods

Front 53

what does a metallic green sheen indicate on an EMB plate? or pink to dark red colonies with a metallic surface sheen on LES Endo agar?

Back 53

These results indicate the presence of coliforms in the completed test

Front 54

What bacterial diseases can be transmitted by polluted water?

Back 54

diarrhea, atypical penumonia, camplyobacteriosis, UTIs, ear infections, cholera, typhoid fever, bacterial dysentery and hemorragic fever,

Front 55

What does a postive colilert-18 test indicate?

Back 55

that fecal colifomrs such as E.coli form human or animal intestinal tracts are present,

Front 56

What does a negative colilert-18 test indicate

Back 56

that total coliforms and E.coli are absent and not in the water sample being tested

Front 57

Why were three different media used in the enumeration of soil microbes expirment

Back 57

because not all the microbes present will grown on any one medium.

Front 58

The three types of media that were used in soil enumeration experiment

Back 58

Sabourauds dextrose agar for fungi

glycerol yeast extract for actinomycetes (filamentous oil bacteria)

TSA - common typical bacteria

Front 59

Would the same results be obtained if the sample was collected during a different time of the year?

Back 59

Yes. vegetable decay may be selective. as well as temp. and soil moisture. and abundance of plants at certain times of the year

Front 60

When general groups of soul bacteria cannot be determinedusing the media and procedures in this exercise?

Back 60

obligate anaerobes

Front 61

what generilations can you make from this exercise with respeect to your garden soil?

Back 61

whether it is alkaline or acidic, (fungi in acidic)

soil fertility based upon amount of microbes present

Front 62

What are some physical features of soil that influence microbial populations

Back 62

porosity, that allow moisture to enter soil

the ph of the shoil

the quantity and availability of nutrients in the soil

Front 63

what is the compostition of glycerol yeast agar?

Back 63

glycerol, agar, ferrous sulfate, sodium propionate, asparagine,

Front 64

Why are different dilutions used for bacteria fungi and actinomyecetes?

Back 64

thbecause in most soils there will be a greater number of typical bacteria, followed by the actinomycetes, and finally the least, comprising fungal isolates

Front 65

Why is a standard plate count perfomed on food products?

Back 65

to determine the number of microbes in 1g of food. if greater than 10^6 per gram it may be hazardous to consume

Front 66

does the number of bacteria recorded by the standard plate count method accurately reflect the total bacterial count from that sample?

Back 66

no because many microbes present may not grow in the medium utilized

Front 67

why are 25 - 250 colonies used for calculations?

Back 67

this range allows a reasonably accurate count while not requiring excessive time to perform

Front 68

why is a 20g sample of hamburger blended with 180ml of diluent to yeild a 1/10 dilution before making further dilutions?

Back 68

the consistincey of the sample would not allow accurate pipetting and subsequent dilutions if not first treated in this manner

Front 69

food poisoning?

Back 69

food containing microbes

Front 70

food intoxication

Back 70

the microbe may no longer be alive, but toxins it produced are in the food

Front 71

why use plant count agar in food procedure

Back 71

grows many of bacteria found in food, is light in color and facilitates colony counting

Front 72

why should hamburger not be repeatedlly frozen and thawed?

Back 72

eacg time it is thawed the microbes increase in number and remain viable upon refreezing

Front 73

could a type AB indivdual receive blood from a type B individual?

Back 73

yes the type AB pereson does not prudce antibodies against type A or type B

Front 74

Who would receive type O blood?

Back 74

all blood types

Front 75

could a person with blood type AB receive blood from a primate with the same blood type?

Back 75

no because it is a different species, and does not have histocompatible antigens

Front 76

why cant u give a type A type B blood

Back 76

the donor blood cells would agglunitate in the recipeintes ciruculatory system by anti-B antiboides already present leading to blocakge of blood vessels

Front 77

What cause clumping to occur?

Back 77

the antigens on the surface of the red blood cellsare bound and cross-linked by specific antibody linking the blood cells together in agllutination complexes

Front 78

What is a hemagglutination reaction?

Back 78

the linking of particulate antigens by antibody resulting in visible complexes

Front 79

what is serotyping?

Back 79

serotyping uses agllutination or precipitin reactions to diagnose an infection in an individual or, as in this exercise to determine the type of antigens on an individuals red blood cells

Front 80

MPN test

Back 80

used to determine water quality, it is a series of test to determine the number of cloiforms in a water sample, consists of a presumptive, confirmed and completed test

Front 81

in the presumptive test

Back 81

watch for a bubble in Durham tube means positive for lactose fermentation by coliforms

Front 82

in the confirmed test

Back 82

use EMB plate to determine the presenceo f E.Coli from the water smaples

Front 83

completed test

Back 83

gram stain for gram negative bacteria

Front 84

Postitive results in the quickvue in-line strep A test?

Back 84

two lines, one red one blue, blue is the control line, red line mean positive for strep

Front 85

Absorbacne equals

Back 85

2-log(%T)

Front 86

alkalinophiles

Back 86

ph between 8.6-11

optimal at 10

Front 87

halophiles

Back 87

salt concetrations at .3-.8 M

extreme at 3.4-5.1 M

Front 88

acidophiles

Back 88

pH at 2.0 or below

Front 89

psychrophiles

Back 89

under 20 degrees C

Front 90

ELISA test does?

Back 90

measures antibodies in your blood, used to determine if you have antibodies related to certain infections and is use to diagnose infections and diseases

Front 91

The entreopluri test is used to

Back 91

identify enterobacteria and other gram negative oxidase negative bacteria

Front 92

in the plaque assay is used to

Back 92

determine the concentrarion of virions

Front 93

why do we dilute the phage suspsension?

Back 93

to avoid overgrowth of number of plaques

Front 94

concentration of plaque forming units (PFU/ml)

Back 94

number of plaques that form in assay / dilution factor

Front 95

Conjugation

Back 95

living bacteria transfers DNA through sex pilus to other living bacteria

Front 96

Transformation

Back 96

living bacteria picks up exogenous DNA from surroundings left behind by dead bacteria

Front 97

Competence

Back 97

ability of a bacteria to gain foreign DNA by transformation

Front 98

Induction

Back 98

using calcium chloride and heat shocking to make a cell competent

Front 99

a plasmid contains

Back 99

an origin of replication, multiple cloing site, promotor, and a selectable marker

Front 100

mutiple cloing site is the

Back 100

area where the gene of choice is inserted using restriction enzymes

Front 101

selectable marker

Back 101

the resistance gene that only allows transformed (cells that has the marker) cells to grow when places on plates with that drug

Front 102

GFP

Back 102

green flurorescent protein isolated from jellyfish, shows green for successful transformation

Front 103

IPTG does what?

Back 103

removes the repressor and allows GFP to be transcribed and expressed

Front 104

The kind of plates used in the transformation

Back 104

ampicillin resistance plates, which is select for transformants

Front 105

purpose of heat shocking the cells

Back 105

it facilitates entry of DNA into cells