Question | Answer |
Which of the following lamps provides a
continuous spectrum of radiant energy in
the visible, near IR, and near UV regions
of the spectrum?
A. Tungsten-filament
B. Hydrogen
C. Deuterium
D. Mercury vapor | Tungsten-filament |
Which of the following isolates light
within a narrow region of the spectrum?
A. Photomultiplier tube
B. Monochromator
C. Photovoltaic cell
D. Detector | Monochromator |
Which of the following is not descriptive of a photomultiplier tube?
A. Emits electrons proportionally to
initial light absorbed
B. Must be shielded from stray light
C. Cannot be used with a chopper
D. Amplifies the initial signal received | Cannot be used with a chopper |
Which of the following is false about a photomultiplier tube?
A. Converts radiant energy (light)to electrical energy (current)
B. Amplifies the current significantly
C. Has a very rapid response time
D. Is composed of an iron plate anda layer of selen | Is composed of an iron plate and
a layer of selenium |
The bandpass of a spectrophotometer is
10 nm. If an instalment is set at 540 nm,
the wavelengths that are permitted to
impinge on the sample will be within what
wavelength range? | 535-545 nm |
Which of the following formulas is an
expression of the Beer-Lambert law that is
routinely applied to spectrophotometric
analysis? | Au x Cs/As=Cu |
In spectrophotometry, which of the
following is a mathematical expression
of the relationship between absorbance
and transmittance? | A = 2 - log %T |
Which of the following may be associated
with reflectance spectrophotometry
as it relates to the dry reagent slide
technique? | Unabsorbed, reflected light detected
by photodetector |
Fluorometers are designed so that the
path of the exciting light is at a right
angle to the path of the emitted light.
What is the purpose of this design? | Prevent excitation light from reaching
the detector |
Which of the following represents
a primary advantage of performing
fluorometric over absorption spectroscopic
methods of analysis? | Increased specificity and increased
sensitivity |
Which of the following may be associated
with fluorescence polarization? | Plane-polarized light is used for
sample excitation. |
Which of the following may be associated
with bioluminescence? | Light emission produced due to
enzymatic oxidation of a substrate |
Nephelometry is based on the measurement
of light that is | Scattered by particles in suspension |
Which of the following instruments is
used in the clinical laboratory or in
reference laboratories to detect beta and
gamma emissions? | Scintillation counter |
Which of the following best describes
chemiluminescence? | Chemical energy excites electrons that
emit light upon return to ground state |
In assaying an analyte with a single-beam
atomic absoiption spectrophotometer,
what is the instrument actually measuring? | Intensity of the beam from the hollowcathode
lamp after it has passed
through the analyte-containing flame |
What is the function of the flame in atomic
absorption spectroscopy? | Bring the metal analyte to its ground
state |
Most atomic absorption spectrophotometers
incorporate a beam chopper and a tuned
amplifier. The purpose of these components
is to avoid errors that would be caused by | Measurement of light emitted by the
analyte |
In potentiometry, which of the following
is considered the standard electrode? | Hydrogen electrode |
In an electrolytic cell, which of the
following is the half-cell where reduction
takes place? | Cathode |
Mercury covered by a layer of mercurous
chloride in contact with saturated
potassium chloride solution is a description
of which of the following types of
electrodes? | Calomel |
When a pH-sensitive glass electrode is not
actively in use, in what type of solution
should it be kept? | The medium recommended by the
manufacturer |
When measuring K+ with an ion-selective
electrode by means of a liquid ionexchange
membrane, what antibiotic will
be incorporated into the membrane? | Valinomycin |
What are the principles of operation for a
chloride analyzer that generates silver ions
as part of its reaction mechanism? | Amperometry and coulometry |
When quantifying glucose using an
amperometric glucose electrode system,
which of the following is not a component
of the system? | Hexokinase reacts with glucose |
To calibrate the pH electrode in a pH/
blood gas analyzer, it is necessary that | Two buffer solutions of known pH be
used |
The measurement of CO2 in blood by means
of a PCO2 electrode is dependent on the | Change in pH because of increased
carbonic acid in the electrolyte
surrounding the electrodes |
The measurement of oxygen in blood by
means of a PO2 electrode involves which
of the following? | Direct relationship between amount of
oxygen in the sample and amount of
current flowing in the measuring system |
Which of the following blood gas parameters
are measured directly by the blood gas
analyzer electrochemically as opposed to
being calculated by the instrument? | pH, PCO2, PO2 |
Which of the following methods allows
for the separation of charged particles
based on their rates of migration in an
electric field? | Electrophoresis |
Which of the following techniques is
based on electro-osmotic flow? | Capillary electrophoresis |
In serum protein electrophoresis, when a
buffer solution of pH 8.6 is used, which of
the following characterizes the proteins? | Exhibit net negative charge |
Which of the following characteristics will
a protein have at its isoelectric point? | Net zero charge |
What dye may be used for staining protein
bands following electrophoresis? | Ponceau S |
When electrophoresis is performed, holes
appear in the staining pattern, giving the
stained protein band a doughnut-like
appearance. What is the probable cause
of this problem? | Protein concentration was too high |
What is the purpose of using ampholytes
in isoelectric focusing? | Establish a pH gradient in the gel |
Which of the following is not associated
with silver stains?
A. Reactive to nanogram concentrations
of proteins
B. Polypeptides stain a variety of colors
C. Not as sensitive as Coomassie brilliant
blue
D. Preconcentration of CSF not
necessary | Not as sensitive as Coomassie brilliant
blue |
Which of the following is not associated
with isoelectric focusing?
A. Continuous pH gradient
B. Migration of proteins with net charge
of zero
C. Separation dependent on isoelectric
point
D. Zone electrophoresis | Migration of proteins with net charge
of zero |
Which of the following is an electrophoretic
technique employing a pH
gradient that separates molecules with
similar isoelectric points? | Isoelectric focusing |
To achieve the best levels of sensitivity
and specificity, to what type of detector
system could a gas chromatograph be
coupled? | Mass spectrometer |
Which of the following instruments has
a sample-introduction system, solventdelivery
system, column, and detector
as components? | High-performance liquid
chromatograph |
Which type of elution technique may be
used in high-performance liquid chromatography? | Gradient |
Which of the following statements best
describes discrete analysis? | Each sample-reagent mixture is handled
separately in its own reaction vessel. |
Which of the following chromatography
systems may be described as having a
stationary phase that is liquid absorbed on
particles packed in a column and a liquid
moving phase that is pumped through a
column? | High-performance liquid |
Which of the following chromatography
systems is characterized by a stationary
phase of silica gel on a piece of glass and
a moving phase of liquid? | Thin-layer |
Ion-exchange chromatography separates
solutes in a sample based on the | Sign and magnitude of the ionic charge |
Which parameter is used in mass
spectrometry to identify a compound? | Ion mass-to-charge ratio |
Which chromatography system is
commonly used in conjunction with mass
spectrometry? | Gas-liquid |
Which of the following may be a
sampling source of error for an
automated instrument? | Short sample, Air bubble in bottom of sample cup, Fibrin clot in sample probe |
Checking instrument calibration,
temperature accuracy, and electronic
parameters are part of | Function verification |
Which globin chains compose hemoglobin
A1? | Two alpha chains and two beta chains |
Which hemoglobin may be differentiated
from other hemoglobins on the basis
of its resistance to denature in alkaline
solution? | F |
Hemoglobin S is an abnormal hemoglobin
that is characterized by a substitution of
which amino acid? | Valine for glutamic acid in position 6
on the beta chain |
When performing electrophoresis at pH
8.6, which hemoglobin molecule migrates
the fastest on cellulose acetate toward the
anode? | A1 |
Because of similar electrophoretic mobilities,
several hemoglobins cannot be
differentiated on cellulose acetate medium.
Electrophoresis of hemoglobins at pH 6.2
on agar gel may be useful in differentiating
which hemoglobins? | C from A2 |
In addition to performing hemoglobin
electrophoresis, a solubility test may be
performed to detect the presence of what
hemoglobin? | S |
Which of the following is not quantified
using an immunoassay method? | Electrolytes |
Which of the following is a homogeneous
immunoassay where separation of the
bound from the free labeled species is not
required? | Enzyme-multiplied immunoassay
technique (EMIT) |
When using EMIT, the enzyme is coupled
to | Antigen |
The enzyme activity measured in the
EMIT is the result of the reaction between
the substrate and coenzyme with | Free labeled antigen |
Singlet oxygen reacting with a precursor
chemiluminescent compound to form a
decay product whose light energizes a
fluorophore best describes | Luminescent oxygen channeling
immunoassay |
Which of the following stimulates the
production of singlet oxygen at the surface
of the sensitizer particle in a luminescent
oxygen channeling immunoassay? | Radiant energy |
Proteins, carbohydrates, and lipids are the
three major biochemical compounds of
human metabolism. What is the element
that distinguishes proteins from carbohydrate
and lipid compounds? | Nitrogen |
Proteins may become denatured when
subjected to mechanical agitation, heat,
or extreme chemical treatment. How are
proteins affected by denaturation? | Alteration in tertiary structure |
What is the basis for the Kjeldahl
technique for the determination of serum
total protein? | Quantification of the nitrogen content
of protein |
When quantifying serum total proteins,
upon what is the intensity of the color
produced in the biuret reaction dependent? | Number of peptide bonds |
Which of the following reagents can be
used to measure protein in cerebrospinal
fluid? | Coomassie brilliant blue |
Which disorder is not associated with an
elevated protein level in cerebrospinal
fluid? | Hyperthyroidism |
Which term describes a congenital
disorder that is characterized by a split in
the albumin band when serum is subjected
to electrophoresis? | Bisalbuminemia |