micro lab exam 1

aspetic technique

a set of protocols or methods used to prevent contamination

• Goal: to prevent contamination of self, culture, environment

• same concept as sterile field

• ex: hand washing, disinfecting work space, working with bunsen burner, autoclaving, keeping personal items away from work spaces

media

food source for growing microbes, artificial growth medium, most media is general purpose (not specific for any given organism)

Agar purpose and media forms

used to make media solid

• broth, slant, deep, plate

broths

liquid medium

• tool: inoculating loop

uses: Grow large numbers of microbes in a small space and determine liquid growth characteristics

 Pellicle – growth that forms a layer at the top of a tube

 Flocculent – growth in clumps throughout a tube (“floaties”)

 Sediment – growth that collects at the bottom of a tube

 Turbid – general cloudiness of solution that indicates growth

petri plates

solid agar form

• tool: inoculating loop

• use: to isolate mixed cultures into colonies

• easiest form of media to contaminate

slants

a solid medium form

• tool: inoculating loop

• use: long term storage (up to 2 months)

deeps

a solid medium

• tool: inoculating needle

• uses:

Determine motility – movement away from the stab line

Determine Oxygen (O2) requirement

field of view

the area of the slide that is observed through the microscope lenses

• working distance: the space between the objective lens and the slide

rheostat

a knob used to increase and decrease the amount of light coming from the illumination source

microscope

shapes of bacteria (3)

• spheres (cocci): staphylococci, streptococci

• rods (bacilli): chains, flagellate rods, spore-former

• spirals