Microbio Lab Quiz 1

Types of microscopes

Compound light microscope bright field, phase contrast, dark-field, fluorescence, electron transmission and scanning

Object resolution Human eye

0.2 m small insect

Bright field microscope

0.2 micromillimeter (microbes)

Electron Microscope

0.2 nm (cellular structures, viruses)

Light source

illuminator

Types of Lenses

Ocular, objectives, condenser

Ocular

10X

Objectives

4X, 10X, 40X, 100X

Iris Diaphragm

at condenser involved in increase or decrease light passing through condenser

Coarse adjustment knob

stage up or down, set sample under focus using 4X

Fine adjustment knob

for sharper image, use with 10x, 40x, 100x adjustment knobs

Total Magnification

determined by multiplying the magnification of the objective lens used (4x, 10x, 40x or 100x) by that of the eyepiece/ocular lens

Parfocal

stays on focus when objectives are rotated

Resolution

minimum distance between two objects that can be distinguished as separate entities

Refraction

bending of light

Culture media provides nutrion for organism growth and requires

Macronutrients, Micronutrients, Growth factor (vitamin, biotin, cobalamin), Trace elements

Energy source

chemical or light

Carbon source

inorganic (CO2) autotrophs, Organic: heterotrophs

Synthetic Chemical composition:

the composition is known, ex: e.coli

Complex chemical composition

composition is not known ex: nutrient broth (beef ectract, peptone, water), TSA

Concentration of agar for liquid, semi-solid, solid

liquid 0%, semi-solid 0.3-0.6%, solid 1-2%

General

most organisms can grow TSA, NA

Selective

growth of one type of bacteria while suppressing other types (mac conkey)

differential

allow the differentiation of colonies of desired organisms from others that grow on the same plate (mac conkey)

Enriched

allow the fastidious organisms to grow (blood agar)

dehydrated media

nutrient broth powder

nutrient agar slant

used to store organism for short period of time

nutrient agar plate

used for isolation of colonies

nutrient broth

used for propagation of culture

mixed cultures

more than one organism in sample

pure cultures

one organism in a sample

From liquid media (nutrient broth)

inoculation of broth (liquid media/propagation), inoculation of plate (solid medium/isolation), inoculation of slant (solid medium/short term storage)

CNA, organism, inhibitor and indication

gram +, colistian, nalidixic acid, - indicator

MacConkey organism, inhibitor and indication

gram -, bile salts, natural red

MSA organism, inhibitor, indication

staphylococcus spp, sodium chloride 7.5%, phenol red

Blood Agar organism, inhibitor, indicator

gram +/gram -, no inhibition, blood hemolysis

gram positive retention

of crystal violet from peptidoglycan

gram negative is

pink!