Microbiology 2420 Lab Practical 1

Learning objectives: introduction to microscopy

correctly name components of a microscope and view microorganisms using every objective

condenser lens

focuses the light allowing for uniform illumination

objectives

light refracts through a series of lenses in the _____ to for magnification of the specimen

magnification

is the apparent increase in size

ocular

the visualization is completed through _______ of the microscope

objective, ocular

the total magnification is calculated by multiplying the _____ times the _______

numerical aperture

the ability of the lens to capture light from the specimen and use it for visual appearance

resolving power

the ability to view two objects as separate entities

learning objectives: Aseptic Technique and pure culture transfers

will be able to know how to use aseptic technique to obtain pure cultures

pure culture

is a culture with only one isolation of microorganism that has been clonally expanded

aseptic technique

is a technique free of microorganism

quadrant streak method

is a technique to streak for isolation of individual colonies

colony

is a single clonal expansion of one bacterium to generate enough cells that it cant be views macroscopically

broth

is a common term for liquid media

agar plate or slant

is a solid form of microbial growth

1.5%

both broth and agar plate/slant contain same nutrients but solid medium has an added ingredient of ______ solidifying agar

4

how many times do you flame the loop during the quadrant streak method

Learning objectives: Simple stain

to learn to stain bacteria for identification and recognize basic bacterial shapes

bacterial smear

after the organism has air-dried, heat-fix by passing through the Bunsen burner flame 3 times

shapes of bacteria

coccus, bacillus, vibrio, spirochete or sprilium

arrangements of bacteria

mono, diplo, tetra, sarcina, staphylo, strepto

Learning objectives: Fungi

Observe a eukaryotic microorganism and compare the differences between eukaryotes and prokaryotes.

yeasts and molds

microscopic fungi are divided into these based on their cellular structure and mechanisms of replication

dimorphic

there are several pathogenic fungi the can take on both forms

yeasts

these replicate through asexual budding unless they are dimorphic. these are more challenging to prepare for microscopy

molds

these generate asexual or sexual spores for replication and dissemination. These are easier than bacteria to prepare for microscopy

conidia/ sporangiospores

the asexual spores

ascomycetes/zygomycetes

the sexual spores are frequently named after the fungal class

2 types of ascomycetes

Aspergillus conidiospores

Penicillium conidiospores

2 types of zygomycetes

Rhizopus sporangiospores

Rhizopus zygospores

learning objectives: Serial dilutions (viable plate counts)

understanding the concept of 10- and 100- fold dilutions used to decrease the concentration of a given sample

30-300

the range for a countable number of cells

TFTC (too few to count)

less than 30 is considered this

TNTC (too numerous to count)

more than 300 is considered this

cfu/ml

colony count should be recorded in

scientific notation

colony count should be written in

# * 1/fdf

how to find the starting concentration of a serial dilution

Learning objectives: Metabolism- Fermentation, Gelatinase, and Indole Tests

Should be able to describe how various differential media can be utilized to develop a greater understanding of the biochemistry of an organism

acid is produced, turns yellow

how do you know if a microorganism has the ability to ferment a particular sugar

phenol red pH indicator

what is added to the media to allow for the detection of acidification

Methyl Green will no longer be detectable

how do you know if the microorganism secretes DNAse

enzyme tryptophanase

what are you testing for with the indole test

a bright red ring

if you add kovac's reagent what will happen if the enzyme is present

bubbles

what happens in the hydrogen peroxide of the enzyme catalase is present

they are eukaryotic, decomposer and have chitin wall

since it looks like a bacterial colony on an agar plate why are yeast classified as fungi

how do conidiospores and sporangiospores differe microscopically

Sporangiospores(contained) are in a sac and conidiospores are not in a sac(free)

which of the following microscopic slides views has structures generated through meiosis

Rhizopus zygospore

which organism served as a negative control for all tests

P. aeruginosa

what can be determined about a microorganism for the motile organism turn red

TTC is added to the medium and turns red after acting as an acceptor

why do we stain bacteria for motility. why cant we stain the bacteria for this exercise

for visibility/ heat fixing would kill so motility could not be determined

phenol red is yellow

less than 6.8

pink at 7.4

2 methods to determine if a bacterium is motile

wet mount preparation (micro), Motility media (macro)

the twitching

brownian motion

complex media

a medium of unknown compositions

defined medium

the exact composition of both reagents and qualities

selective media

favors the growth of some bacteria while inhibiting the growth of others

differential media

visible color change that can give more info about a microbe (ability to ferment sugars)