chapter4 (diana's version) microscopy Flashcards
what does the term compound mean ?
the term compound mean, there is two things happening at once
what uses a light bulb to energize the specimen
compound light microscope
name the three kinds of electron microscopes
scanning electron microscopy
scanning transmission microscopy
and scanning tunneling microscopy
what is the first to magnifying what ever is on the slide?
objective lens
name the microscope that contains a short wavelength and a long wavelength?
light microscope are typically the one with longer wavelength, and electron microscope are the ones with shorter wavelength
does a microwave have a long or short wavelength?
it has a long wavelength
light microscope is fine for not fine detailed such as bacteria?
false, if we are elaborating on bacteria we need to use an electron microscope
would the number be higher or lower (numerical) on electron microscope?
it would be lower since the resolution would be better
the smallest object visible wit the human eye is ______ mm. What is it numerically?
0.10 mm, it would be 0.10 10^-3 meter
a compound microscope can be used to view an object as small as ____, what is it numerically?
0.2 um, 10^-6 micrometer
an electron microscope can be used to view objects as small as _____.
0.20 nm, 10^-9 nanometer
True or false. Using the same magnification an electron microscope will also provide an image with a better resolution than a light microscope?
true
elaborate on transmission electron microscope
used to examine internal structure
electron beams do not penetrate the thick cell well, which requires the cell to be cut in order to be viewed, this process is called thin sectioning
these thin sections must be stained before they can be viewed under the TEM
used for extracellular structure and research purposes
scanning electron microscopy
define what scanning tunneling microscopy
this is the most powerful of the electron microscopes
it is used to visualize atoms
staining procedure: define it
1) a thin film of material called a smear which contains the microorganisms of interest is smeared on a slide
2) the sample is then fixed by passing through a flame
3) stain is then applied to the sample
(flooding, because we add a lot of stain)
4)the stain is removed from the sample by rinsing
5) the stained sample is now viewed under a microscope
what does a gram stain determines?`
determines whether a bacterium is gram positive or gram negative
on the stain procedure, passing through a flame will do what on the sample?
passing through a flame will dehydrate the sample
what does amordant do?
amordant, intensify things such as iodine
sticking to every cell is what kind of charge?
positive charge
acid fast-chain define it
this stain binds strongly bacteria that contain a waxy cell wall component (mycolic acid).
elaborate why mycobacterium tuberculosis and other members are positive but does not appear purple
they are gram positive but they do not appear purple, since they have another layer and what they put on that is myocolic acid, anything that has a charge is hydrophilic, it cannot do gram stain on mycobacterium since they have that outer layer
The waxy cell wall of the mycobacterium retains carbol fuschin that is added, what does this do?
stick the wax to the hydrophobic, so this is also hydrophobic
if positive for myobacterium it would appear to be pink and blue
True
if not positive for myobacterium what color would it be?
methylene blue
capsule stain:
this is a positive charged chromophore but it also uses a negative charge chromophore
true
is safranin a positive stain?
it is.
what color does endospore stain appear if they are a positive stain?
pink and green
simple staining: name the purpose and the principle
purpose is to determine the morphology,
the principle: basic dye with net positive charge that can bind to the bacterial membrane that has a net negative charge
this is not a differential stain, therefore there isn’t a positive or negative
negative staining : determine the purpose and principle
purpose: determine the morphology
principle: acidic dye with a net negative charge that is repelled by bacterial membrane that also has a net negative charge
positive/negative: is not a differential stain, therefore there is no negative or positive. we used nigrosin dye which gave a uniform black background. bacteria appeared as a clearing in the background bc they repelled the dy
gram stain, determine the purpose, and the principle
purpose: to determine the gram stain as positive or negative
staining principle : positive or negative depends on the cell wall (peptidoclycan) thickness.
net positive crystal violet intercalates into cell wall, iodine act as a mordant to fix crystal violet in place. Crystal violet/iodine washed out of gram negative cell wall with acid alcohol. gram negative cells counter stained with simple stain safranin
acid fast stain, principle and purpose
purpose is to identify the acid fast bacteria
staining principle: due to the presence of mycelia acid in the cell wall some bacteria most dyes including gram stain can’t penetrate the cell wall to reliable stain.
Heat is require to drive carbon funschin dye into the myocolic acid cell wall. slide is countered stained with the simple stain methylene blue.
determine the purpose and principle of stain capsule
purpose is to stain capsule
principle: bacterial capsules are an important of differential stain to identify. capsule positive bacteria who are often virulent pathogens.
what is energy in terms of resoltion
energy is wavelength
high energy or shorter wavelength has the ability to what?
to destry your dna and cause cancer and incredibly destructable
true or false: in scanning electron microscopy the specimen must be coated with a thin film of heavy metal
true
true or false. IT DOES NOT HAVE TO BE PURPLE as a positive, but rather it depends on the chosen one, knowing the cell is negative is an important though
true
this is a matter of yes or no, no specification, no differientation that comes off the simple stains
- they have stains, they have a charge and make them color whatever chromophore is
what is this?
simple stains
when you add alcohol, in the gram stain procedure, if it’s a negeative infection, what will happen to the purple dye?
the purple dye washes out, why? because you are deoclorizing it
is flagella a thin or thick cell
it is a thin stain, they are too small to be seen under light microscope without stain
