Micro Lab

Front 1

Working in a way that minimizes escape of microorganisms from culture tubes or plates. Also, working in a way that minimizes contamination of your samples with outside environmental organisms

Back 1

Aseptic Technique

Front 2

Gram + cells are

Back 2

Staphylococcus aureus (purple)

Front 3

Gram – cells are

Back 3

Escherichia coli (pink)

Front 4

Aerobic=Requires oxygen to grow

Back 4

Aerobic

Front 5

Does not require oxygen, and most cannot grow in its presence

Back 5

Anaerobic

Front 6

The presence of Oxygen causes accumulation of peroxide (H2O2) which must be converted into water and hydrogen by the enzyme Catalase to avoid cell damage by free radicals.

Back 6

2 H2O2 → 2 H2O + O2

Front 7

Thus anaerobes often found in

Back 7

the mouth, in wounds, and in gut perforations

Front 8

Most Anaerobes lack

Back 8

Catalase

Front 9

Faculative Anaerobes can grow _____ a broth

Back 9

throughout dispersed evenly

Front 10

Obligate Anaerobes can grow __________ a broth

Back 10

At the bottom of a tube, away from 02 (oxygen)

Front 11

Microaerophiles can grow ________ in a broth tube

Back 11

small amounts of
catalase and superoxide dismutase

Front 12

E. Coli

Back 12

Facultative anaerobe

Front 13

Micrococcus luteus

Back 13

aerobe

Front 14

Clostridium perfringens

Back 14

anaerobe

Front 15

Methylene blue indicator assures lack of

Back 15

O2

Front 16

(# PFU/volume plate) x (1/dilution of the tube counted)

Back 16

Original concentration of phage stock =

Front 17

1 PFU =

Back 17

1 plaque forming unit

Front 18

) In order of their use, please list the four liquids used during the gram stain procedure

Back 18

1. crystal violet, 2. Gram’s iodine, 3. alcohol, 4. Safranin or counterstain

Front 19

) Briefly describe what is the purpose/function of liquids Iodine, Alcohol

Back 19

. Gram’s iodine – forms large complexes with crystal violet
3. alcohol – shrinks peptidoglycan in cell wall of gram positive cells to hold stain inside, dissolves lipids in outer membrane of gram negative cells to let stain out

Front 20

E. coli:

Back 20

Gram negative, short rod

Front 21

S. epidermidis

Back 21

Gram positive, cocci in clusters

Front 22

Why can’t most anaerobes grow in the presence of oxygen?

Back 22

They are unable to break down the toxic products of oxygen because they lack the enzymes superoxide dismutase (breaks down superoxide) and catalase (breaks down hydrogen peroxide

Front 23

means bacteria are able to take up DNA

Genes on newly acquired DNA are expressed, conferring new characteristics to the bacteria

Back 23

Competent

Front 24

pBluescript SK+ has intact lacZ gene

Back 24

makes colonies BLUE

Front 25

Second plasmid has a gene interrupting lacZ
lacZ is no longer functional,

Back 25

therefore colonies are WHITE

Front 26

__________ helps plasmids enter cells

Back 26

“Heat shock”

Front 27

__________is cleaved by LacZ to make blue pigment

Back 27

X-gal

Front 28

________ distinguishes organisms with hemolytic activity

Back 28

Sheep Blood agar plates:

Front 29

A selective media used to culture fungi; has a low pH and gentamicin

Back 29

Sabouraud agar

Front 30

A selective media used to culture Staphylococcus aureus. Contains mannitol and high salt, and phenol red.

Back 30

Mannitol salt agar

Front 31

Conjugation is

Back 31

horizontal gene transfer
is contact dependent

Front 32

Kirby-Bauer technique

Back 32

Discs carrying known concentration of antibiotic drug placed on a lawn of bacteria plated on Mueller-Hinton agar

Front 33

: Kills or inhibits microorganisms on inanimate surfaces

Back 33

Disinfectant

Front 34

: Kills or inhibits microorganisms on tissue

Back 34

Antiseptic

Front 35

______ agents are lethal to bacteri

Back 35

Bactericidal

Front 36

_______ agents slow the bacteria down (can be baceriocidal at higher concentrations).

Back 36

Bacteriostatic

Front 37

Indirect Elisa tests for _____

Back 37

antibody

Front 38

Direct Elisa tests for

Back 38

antigen

Front 39

Factors which determine size of ZOI
(zone of inhibition)

Back 39

Ability of drug to diffuse
Size of inoculum
Time since inoculation (organism’s growth rate)
Organism’s sensitivity
Condition of the media

Front 40

Types of Oxidizing agents, bacterial acids

Back 40

chlorine, iodine, peroxide

Front 41

Example of Protein denaturing, lipid solvent

Back 41

alcohol

Front 42

What does it mean if a cell is “chemically competent”?

Back 42

Cell has been chemically treated (with calcium) to induce it to take up foreign DNA.

Front 43

What does “insertional activation” mean?

Back 43

One gene has been inserted in the middle of another gene, causing the gene to be disrupted so that a functional protein cannot be produced.

Front 44

What is the purpose of including a selectable marker on a plasmid?

Back 44

Allows you to identify cells containing the plasmid of interest. Cells lacking the plasmid will not grow because they do not carry the selectable marker

Front 45

Name one way bacterial conjugation may benefit a bacterium and one way bacterial conjugation is useful for scientists?

Back 45

Conjugation allows bacteria to exchange beneficial traits, such as antibiotic resistance. Scientists can use conjugation to map the location of genes in the bacterial chromosome.

Front 46

How does mannitol salt agar allow us to differentiate S. aureus from other Staphylococcus species?

Back 46

All Staph species can grow, but only S. aureus can cause yellow color change. This happens when S. aureus ferments the mannitol, causing the pH to drop, which turns the phenol red indicator yellow.

Front 47

Why is it important that only a single strand of genetic material be transferred during conjugation?

Back 47

One strand must be transferred and one strand must be left behind so that both the donor and recipient cells receive a copy.

Front 48

Purple at bottom of tube =

Back 48

positive for ODC

Front 49

Indole test tests for breakdown product of tryptophan, is Kovac's reagant turns ____ then its positive

Back 49

Pink/red

Front 50

In Urease tst, a raise in pH results in ________

Back 50

phenol red indicator turning to bright pink

Front 51

If enzyme is present, in oxidase test, substrate is oxidized, bacteria will turn

Back 51

purple/black

Front 52

Streptococcus viridans-

Back 52

shows alpha hemolysis
\greenish color change

Front 53

S. aureus

Back 53

shows beta hemolysis (loss of red color)

Front 54

Enterococcus faecalis

Back 54

Gamma hemolysis (NO) no color change, agar remains red

Front 55

________ means citric acid was broken down into CO2, which combines with sodium to make sodium bicarbonate, increasing the pH. Turns agar from green to blue

Back 55

Positive Citrate Utilization Medium result

Front 56

Motility Indole Ornithine

Back 56

Butt should be greyish/purple if organisms breakdown ornithine, pH

Front 57

: produce tryptophanase to break tryptophan into indole

Back 57

Indole positive organisms

Front 58

Staphylococcus Aureus

Back 58

Gram + coccus, catalase positive (bubbles), coagulase positive (agglutination)

Front 59

Streptococcus pneumonia

Back 59

Gram + coccus, catalase negative (no bubbles), alpha hemolysis, P disc sensitive (doesn't grow)

Front 60

E faecalis

Back 60

Gram + coccus, catalase negative {(no bubbleS), bile esculin positive

Front 61

_____ hemolysis=clear, but may be faint

Back 61

Beta hemolysis

Front 62

___ hemolysis= greenish/incomplete

Back 62

Alpha hemolysis=

Front 63

______hemolysis= No hemolysis

Back 63

Gamma

Front 64

Mannitol salt agar is selective for

Back 64

Staphylococcus species

Front 65

MacConkey agar is used for

Back 65

selective for Gram negative bacteria because of crystal violet and bile salts which inhibit Gram positives; and differential between lactose fermenters (red or deep pink colonies) and non-lactose fermenters (clear to very pale pink)

Front 66

Blood agar is used for

Back 66

differential for hemolysis

Front 67

If a microorganism can use citrate then

Back 67

pH will rise and pH indicator will turn bromthymol blue

Front 68

Motility-Indole-Ornithine Decarboxylase Medium (MIO) is used to identify members of the _______ species

Back 68

Enterobacteriaceae

Front 69

In urease test when ammonia accumulates the medium becomes alkaline changing the ____ indicator to _____

Back 69

pH indicator to bright pink

Front 70

In Oxidase test, When a drop of the test reagent is placed on filter paper with an oxidase positive organism the colonies turn

Back 70

purplish-black this means positive reaction

Front 71

Oxidase test distinguishes Neisseria sp. and Pseudomonas sp. from

Back 71

members of the Family Enterobacteriaceae which are negative

Front 72

Staphylococcus aureus should ferment the mannitol in the agar and turn the phenol red pH indicator

Back 72

yellow

Front 73

If a species of bacteria ferments sucrose and/or lactose (in addition to glucose), all the agar in the tube will turn yellow due to the drop in the pH from the fermentation of so much sugar

Back 73

A/A

Front 74

if only glucose is fermented, the agar in the butt will turn yellow from the acid produced during fermentation.

Back 74

K/A

Front 75

Positive interpretation of ODC

Back 75

turbid purple to faded out grayish-yellow at the bottom of the tube

Front 76

Negative interpretation of ODC

Back 76

: bright, clear yellow at the bottom of the tube`

Front 77

Enterococcus faecalis is _____

Back 77

gamma hemolytic

Front 78

Streptococcus viridans (not sensitive to P disc) and Streptococcus pneumoniae (sensitive to P disc)

Back 78

are alpha hemolytic

Front 79

Streptococcus pyogenes & Streptococcus agalactiae are

Back 79

beta hemolytic

Front 80

In the presence of bile, ___________, such as _______, have the enzymes to hydrolyze esculin to a product that reacts with the iron salts in the medium turning it into a brown to black color for a positive reaction

Back 80

Group D streptococci
E. faecalis