Med Micro Lab 1

pure culture

a culture containing a single kind of microorganism

specimen of a pure culture all belong to the same ________ and _______

genus and species

aseptically

without contamination of yourself, others, the environment, the source culture, or the medium being inoculated

broths

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

broths should always be ______ prior to transferring

mixed

agar slants

used to grow stock cultures that can be refrigerated after incubation and maintained for several weeks

agar slants require a _________ inoculation, made by moving the loop back and forth

fishtail

plated media

used for obtaining isolation of species

what should be labeled on a broth/slant tube

name, media in tube, source of inoculation, organism

transfers can be made between _____ forms of media

all

what are the transfer instraments?

inoculating loop and needle

mixed culture

microbial culture consisting of two or more species

streak plate technique

bacterial sample streaked over surface of a plated agar medium

colony forming unit

measure of viable microorganisms capable of growing into a colony

A colony-forming unit always refers to a single microbial cell that, if given ideal growth

conditions, is capable of of founding a colony or population.

when are quadrant or t streaks done

with samples of high cell density

when are zigzag streaks done

with samples of lower cell density

how many times is the loop flamed during a quadrant streak?

4

all streaking methods are designed to...

separate CFUs on agar surface so individual cells grow into isolated colonies

many microorganisms are ___________

nonpathenogenic

saprophytes

decompose organic matter

mutualism

A relationship between two species in which both species benefit

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

are commensalistic microorganisms always non-pathenogenic?

no

opportunistic

capable of producing a disease state

resevoir

where a microbe resides and serves as a potential source of infection

many microorganisms are _______-living and do not depend on a host

free

what are the rules for aseptic transfers

Minimize potential contamination

Be organized

Place all media tubes in test tube racks

Take your time

Never hold a test tube by its cap

Hold inoculating loop like a pencil

Ensure Bunsen burner has inner and outer loop

what substances were used in this lab?

S. epidermidis and M. Luteus

what is the first step in a quadrant streak

streak sample in first section

what is the second step in a quadrent streak

flame then drag from first section to second

what is the third step in a quadrant streak

flame then drag from second to third section

what is the fourth step in a quadrant streak

flame then drag from third to fourth section

what is the first step in a T streak

streak sample across top large section

what is the second step in a T streak

flame then drag 2/3 times from first region to second, then 4/5 more times only in second section

what is the third step in a T streak

flame then drag 2/3 times from second to third section, then 4/5 more times only in third section

how is a zigizag streak performed

drag cotton swab in zigzag pattern while rolling swab

agar plates are _________ ________

solid media

what are the types of agar media?

tryptic soy agar, nutrient rich media, selective and differential media

you always label a petri plate on the _________ side

agar (not lid)

what temperature are plates incubated at?

37 degrees Celsius

inoculating loops are sterilized by...

flaming

what is the first step in species ID

obtaining a pure culture

A common isolation method that is typically utilized is the...

streak plate

what can a streak plate do

separate mixed cultures or assess purity

during streaking, the cell _________ decreases

density

Cells that have been sufficiently isolated will grow into colonies consisting of ________ __________ of the original cell

genetic copies

base of microscope

condenser of microscope

stage of microscope

objective lenses

coarse adjustment knob

fine adjustment knob

ocular lenses

magnification

number of times an object is enlarged

Total Magnification

magnification of objective lens times the magnification of ocular lens

Resolving Power

the ability to discern two points

resolving power __________ as magnification increases

increases

resolving power depends on...

wavelength of light and the numerical aperture

Numerical Aperture

the ability of a lens to gather light

Working Distance

the distance between an objective lens and the slide specimen.

why do we use oil immersion

Oil has same refractive index of glass and prevents light loss and bending, results in clearer image