BIOL 351 Lab Exam 1

nonpathogenic/free-living

• does not reside in a host

• not known to cause disease

saprophyte

• decomposes organic matter

• not known to reside in a host

pathogen

causes damage in host

mutualism

a system where both the host and microbe benefit

commensals

a system where the microbe benefits, but there is no effect on the host

opportunistic pathogens

• capable of producing disease in the right part of the body

• many are mutualistic/commensal

resevoir

any area where microbes with the potential to cause infection reside

hemolytic

the purpose of blood agar is to differentiate bacteria based on \_______________ characteristics

5% sheep blood

the composition of blood agar is \_______________ in Tryptic Soy Agar (TSA) base

Tryptic Soy Agar (TSA)

the composition of blood agar is 5% sheep blood in \____________________ base

hemolysins

• exotoxins produced by some Gram (+) cells

• induce hemolysis

streptolysins

hemolysins produced by streptococci

β hemolysis

• hemolysis resulting in the complete destruction of cells

• characterized by a clearing of the medium

• means lots of hemolysins are produced

α hemolysis

• partial destruction of cells

• results in a greenish discoloration of the medium

γ hemolysis

• cells are not destroyed

• medium is not changed

• no hemolysis occured

germicides

• substances/systems (both chemical and physical) that prevent the spread of pathogens

• some are specific, but most are broad-spectrum

decontamination

• the lowest level of microbe control

• reduction of pathogenic microorganisms to a level at which items are safe to handle without protective attire

• usually soaps/detergent

• removes most organic and inorganic matter

disinfection

• medium level of microbe control

• three levels (low, medium, high) based on effectiveness

• do not kill spores, but kill most, if not all, pathogens

• typically liquid, but can be gas/solid, UV light, heat

chemical sterilant

a high level disinfectant with the ability to kill all vegetative cells and some spores

antiseptic

designed to reduce/eliminate pathogens on or in living tissue

sterilization

• the highest level of microbe control

• complete destruction of life, including spores

• chemicals, gas, incineration, heat, ethylene oxide

steam sterilization

the most effective form of sterilization is \______________ \______________

autoclave

• super-heated steam under pressure to kill heat-resistant organisms

• method in BIOL 351 labs: 121°C-127°C for at least 15 min

• time varies according to size and consistency of material

autoclave tape

an autoclave effectiveness indicator that is adhered to something being autoclaved and comes out having changed color if the autoclave was effective

special thermometers

• an autoclave effectiveness indicator that measures the maximum temperature achieved by the autoclave

• drawback: does not record any dips in temperature

biological indicators

• vials with ampule of fermentation broth with pH indicator + strip of filter paper with bacterial spores

• used to assess autoclave effectiveness

geobacillus stearothermophilus

the bacteria used in biological indicators to assess autoclave effectiveness

55°C; 48 hrs

once the inner glass ampule has been crushed in an autoclave biological indicator, the vial must be incubated at \________ for \__________.

not change color; purple

if the autoclave was effective, the biological indicator broth will \_____________ after incubation, meaning it will be \____________.

yellow; acid

if the autoclave was not effective, the biological indicator broth will turn \___________ after incubation, indicating that the bacteria within are alive and producing \____________.

micropipettes

used for transferring small amounts of liquid

P1000 micropipette

max volume: 1 mL (1000 µL)
min volume: 0.2 mL (200 µL)

P200 micropipette

max volume: 0.2 mL (200 µL)
min volume: 0.02 mL (20 µL)

P20 micropipette

max volume: 0.02 mL (20 µL)
min volume: 0.002 mL (2 µL)
- can measure decimals of µL's

P200

when transferring 200 µL of solution, the \___________ micropipette is preferred

high; low

it is better to measure at the \________ end of a pipette than the \_________ end.

growth

influenced by nutrient availability, temperature, and incubation time

punctiform

when a bacterial colony occurs in tiny, pinpoint dots

entire

smooth margin with no irregularities

undulate

wavy margin

lobate

lobed margin

filamentous

unbranched strands (type of margin)

rhizoid

branched strands (type of margin)

raised

type of elevation

pulvinate

extremely convex elevation

umbonate

type of elevation

butyrous

buttery texture

filiform

dense and opaque with smooth edges (growth pattern on slants)

friable

crusty (growth pattern on slants))

spreading edge

growth pattern on slants produced by motile organisms

pellicle

• growth pattern in broth

• growth floats on top

sediment

• growth pattern in broth

• growth sinks

uniform fine turbidity

• growth pattern in broth

• cloudy

flocculent

• growth pattern in broth

• clumped growth

aseptic transfer

transfer technique that does not contaminate the culture, medium, or surroundings

before and after

to prevent contamination, sterilize inoculating instruments \____________ use.

culture

microbe + medium

pure culture

a culture containing only one species

mixed culture

a culture containing more than one species

mixed

before isolation, all cultures are assumed to be \_________

broth

medium used to grow microbes when fresh cultures or large numbers of bacteria are required

slants

medium used to grow stock cultures to refrigerate after incubation for weeks

plates

medium used for obtaining isolation of species, differential testing, and quantifying bacterial density

bottom

you should always label Petri dishes on the \_________

vortex

if broth growth is pellicle/sediment, you must \__________ before taking a sample

colony forming units (cfu)

1 cell, 2 cells, or a cluster of cells where all the cells are identical species

streak

the purpose of the \________ plate method is to obtain isolated cell colonies

lowers

streaking \_________ the density of cells

quadrant streak

streak plate method used for samples with high cell density

zigzag streak

streak plate method used for samples with low cell density

\# colonies/(dilution factor × vol. (mL))

cfu/mL

cfu/mL

a quantification of cell density

spread plate method

• uses serial dilution to reduce cell density

• can be used to begin pure cultures or quantify the cell density of a broth culture

30; 300

the cfu should never be below \_______ colonies or above \_______ colonies

pour plate method

• cannot be used to estimate density because some colonies are embedded in the surface of the medium

• yields isolated colonies of bacteria and fungi

• uses serial dilution and molten TSA medium

4x lens

scanning power objective lens

10x lens

low power field objective lens

40x lens

high power field objective lens

100x lens

oil immersion objective lens

10 (ocular magnification) × objective magnification

total magnification \= ?

real

the objective lenses produce a \________ image

virtual

the ocular lenses produce a \_________ image

oculars

revolving nosepiece

objective lens

stage

iris diaphragm lever

~1300x

the limit of light microscopy magnification

limit of resolution

• actual measurement of how far apart two points must be for a microscope to view them as separate

• inversely proportional to resolution

~0.2 µm

best limit of resolution for a light microscope

Kohler illumination

• produces more uniform and higher quality illumination

• requires a field diaphragm

• allows focusing of light source on specimen

coccus/cocci

spherical cells

bacillus/bacilli

rod-shaped cells

coccobacillus/coccobacilli

short rod-shaped cells

spirillus/spirilli

screw shaped cells

vibrio

curved rod-shaped cells

spirochetes

flexible screw-shaped cells

pleomorphism

• a single species with multiple cell morphologies

• very rare

\# of planes of division

cell arrangement is determined by the \__________________.

diplococcus

- one plane of division