What structure does light pass through after leaving the condenser in a compound light microscope
specimen
Which of the following pair is matched
a) methylene blue - simple stain
b) acidic dye - capsule stain
c) crystal violet - simple stain
d) alcohol-acetone - descolorizer
e) crystal violet - basic dye
f) iodine- mordant
g) carbolfuchsin - basic day
Which of the following steps of the Gram stain are in correct order?
a) Crystal Violet
b) Iodine
c) Alcohol acetone
d) Safranin
Which of the following is true regarding the acid-fast stain
a) It is used to identify members of the genus Mycobacterium
b) acid-fast cell retain the primary dye after treatment with acid-alcohol
c) acid fast cell appear red in a completed acid fast stain
d) non-acid-fast microbes appear blue in a completed acid-fast stain
The purpose of a mordant in the Gram stain is to
prevent the crystal violet from leaving the cells
Which of the following steps is correct regarding to specimen slide preparation?
a) making a smear
b) fixing
c) staining
The negative stain is used to
visualize capsule
Simple staining is necessary to improve contrast in which microscope?
compound lightt microscope
Which microscope is used to see internal structures of cell in a natural state?
phase contrast microscope
Which microscope uses visible light?
differential interference contrast (DIC) microscope
Which microscope has the highest magnification and greatestt resolution?
electron microscope
Which microscope produces an image of a light cell against a dark background; internal structures are not visible
darkfield microscope
A virus measures 100 nm in length. What is its length in um?
0.01 um
Which microscope is not useful for observing living cells?
scanning electron microscope (SEM)
A microorganism measures 5 um in length. Its length in mm would be
0.005 mm
Which of the following correctly traces the path of light through the compound microscope?
a) light source
b) condenser
c) specimen
d) objective lens
e) ocular lens
Which microscope is used to observe a specimen that emits light when illuminated with an ultraviolet light?
fluorescence microscope
Which microscope is most useful for visualizing a BIOFILM?
scanning acoustic microscope (SAM)
You are performing a Gram stain on gram positive bacteria and you stop after the addition of the first dye. What is the appearance of the bacteria at this point?
purple
You are performing a Gram stain on gram negative bacteria and you stop after the addition of the mordant. What is the appearance of the bacteria at this point?
purple
You are performing a Gram stain on gram negative bacteria and you stop after the descolorizer. What is the appearance of the bacteria at this point?
colorless
You are performing a Gram stain on gram positive bacteria and you stop after the addition of the counterstain. What is the appearance of the bacteria at this point?
purple
Which type of stain is useful in helping clinicians to decide which antibiotic to prescribe for a bacterial infection?
Gram stain
What is the total magnification of a specimen viewed with a 10x ocular lens and a 40x objective lens?
400
Which of the following provides the lowest magnification ?
scanning electron microscope (SEM)
Which microscope uses two beam of light to produce a three dimensional color image?
DIC microscope
Which microscope is used to see intracellular detail in a living cell?
two-photon microscope
Which microscope is used to observe viruses and the internal structure of thinly sectioned cells?
transmission electron microscope (TEM)
Which step in the Gram stain is the critical step in differentiating gram positive cells from gram negative cell?
alcohol-acetone
You find colorless areas in cell in a gram stained smear. What should you apply next?
an endospore stain
Which microscope is used for observing the surfaces of cell and viruses
scanning electron microscope (SEM)
The resolution of a microscope can be improved by changing the
wavelength of light
The term resolution refers to
the ability to distinguish fine structure and detail in a specimen
The courterstain used in the Gram stain is a basic dye
True
Both phase-contrast microscopy and differential interference contrast microscopy are used to view the internal structures of cells without staining
True
The capsules and flagella of bacteria can be observed in gram stained smears
False
Scanned probe microscopy is used to examine fine detail of molecular complexes, such as blood clots, molecules or DNA
True