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
