Chapter 4 Flashcards
Staining and Microscopy
Resolution def
distinguish 2 points that are close together
high resolution means what
higher ability to distinguish two objects
contrast def
differences in intensity between two objects or between an object and its background
what does staining do to contrast
it increases it
light microscopy , contains what
the bright field microscope, dark field, fluorescence, and confocal
bright field microiscope
simple, single, magnifying lens OR
compound, multiple magnifying lens
imersion oil does what
causes the light passing through the specimen to remain un retractive, this increases resolution and more light is able to pass through
dark field microscopes are best for what
observing pale, small, or colorless objects
fluorescence microscopes do what
use direct UV light source at specimen. some cells are naturally, some are dyed with a fluorescent dye
confocal microscopes do what
use fluorescent dyes and UV lasers to illuminate a sample in a single plane. then a computer constructs 3D image
2 types of electron microscopy
transmission electron microscopes, and scanning electron microscopes
Electron miscroscopy can magnify objects how much
10,000 to 100,000
Transission electron def
you can view inside the cell , its very large and expensives
scanning electron
view the surface of the cell
Staining helps do what
increase contrast and resolution
simple stains do what
are compsed of single basic dye and are used to determine size, shape, and arrangement of cells
Differential stains do what
use more than one dye and distinguish between different cells, chemicals, or sturctures
common differential stains
gram, acid fast, endospore, histological
Step 1 of gram stains
initial stain (crystal violet)
step 2 of gram stains
mordant forms complex (Iodine)
I forms complex with the CV.
Step 3 of gram stains
decolorization, (ethanol) to shrink the peptidoglycan layer.
The complex stays in G+ and leaves G-
Step 4 of gram stains
the Counter stain (safranin), to dye the remaining colorless G- cells
Ziehl-Neelsen Acid Fast stain for what
for acid-fast bacteria, its waxy mycolic acid, and gram staining doesnt work weell
Schaeffer-Fulton Endospore Stain
the endospore is stained green
two types of histological stains
hematoxylin and eosin (HE) stain
Gomori methenamine silver (GMS) stain
what is a histological stain for
tissue
special stains are used for what
to identify specific microbial structures
what are 2 types of special stains
negative stains and flagellar stains
Negative capsule stain does what
stains for capsule, so there is color everywhere except for the structure of interest . the colorless areas are the capsule
flagellar stain
morphology of flagella
why is a g- bacterium colorless but a g+ bacterium is purple after rinsed with decolorization
the g- peptidoglycan is thin and the g+ peptidoglycan layer is thick
some bacteria is not effectively stained with the gram stain becauseeee
they have large amounts of waxy lipid in their cell wallsm
unit of measurement for prok cells
micrometer
What did linnaeus propose
only 2 kingdoms, plants and animals
Taxonomy def
the science of classifying and naming different organisms
domains def
comparing genetic material of organisms
what did carl woese do
he compared nucleotide sequences of rRNA of ribosomes
proposal of 3 domains. what are they. how is it determined
archaes, euk, bacteria, determined by ribosomal nucleotide sequences
Universal phylogenetic tree does what
compares sequence of small subunit rRNA
LUCA
Last Universal Common ANcestor
what are the 6 means of identifying different microbes
physical characteristics
biochemical tests
serological/antibody tests
phage typing
MALDI/TOF mass spectrometry
Analysis of nucleic acids
physical characterisitcs info
shape, structure, etc. indentify based on morphology
biochemical tests info
to determine utilization or production of certain chemicals, to help identify pathogens
phage typing infor
bacteriophages are viruses that infect bacterial cells, so very specific to host, and are an alternative to antibiotics
Taxonomic Keys ex
dichotomous keys
dichotomous keys are what
a series of paired statements where only of of two “either/or” choices applies to any particular organism
the key directs to another statement or name of organism
how many basic shapes for bacteria
3
dichotomous taxonomic key is used for what
like a chart to identify a name of something
