Lecture 2 Flashcards
types of microorganisms
bacteria, fungi, algae, parasites, viruses
non cellular microbes
viruses
procaryotes
bacteria
another procaryote, not pathogenic
archaea
earliest life forms ___ years ago
3.8 billion
groupings can be assembled into bacterial _____
taxonomic tree
scientific name for bacteria uses
binomial nomenclature
bacteria species further divide into ___
strains
what is the value of bacterial taxonomy?
consistency, relatedness, medical practice
this is sufficient for most routine observation
light microscopy
light microscope obtains up to _____x magnification
1000
magnification up to 200 000x with this
electron microscopy
why stain?
increase contrast/highlight, preserve
prob of stain?
kills microbe
what to do to have living bacteria observed:
hanging drop (wet mount)
prob of wet mount?
poor contrast
point of fixing?
kill, stick, bind dye
thin layer of bacteria on glass slide called:
smear
types of stains
simple (single dye), differential (multi dyes)
example of differential stain?
gram stain
gram negative is __ colour, positive is ___ colour
pink/red, purple
how does gram stain work?
primary purple stain, iodine lets bind better, alcohol remove stain from gram negative only, counterstain with safranin
if bacteria identified, lab also test for :
susceptibility
another ex. of diff. stain?
acid fast stain
