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BLD 313 Exam 3 (Quizzes 5&6)

Terms in this set (58)

Which of the following is an example of semi-quantitative test result?
3+
Which of the following signals is light based?
Absorbance
Which of the following measures the signal change in magnitude?
Amplitude
Which of the following overestimates the concentration?
Upward drift
Which of the following statement is NOT true about analytic range?
Analytic sensitivity is defined by the last data point on the standard curve
What is the molar absorptivity of a compound which produces an absorbance (A) of 0.250 at a concentration of 0.2 moles/liter in a cuvette path width of 2 cm?
0.625L/M∙cm
A chromophore has a molecular weight of 150. When 20 mg of this substance is placed in 500 ml of water, it produced an absorbance of 0.250. What is the molar absorptivity of this compound? (The cuvette path width is 1 cm).
937.5L/M∙cm
The concentration of a solution is 10M. It has an absorbance of 0.200 when placed in a 1.0cm cuvette at the wavelength of 250nm. What would be the absorbance if the solution is 5M?
0.100
A compound has a molar absorptivity of 1.50 x 10-2 l/m cm. if 1.00 ml of a solution containing this compound is placed in 5 ml of water, this final solution produced and absorbance of 1.500. What is the concentration of this compound in the original solution?
0.06M
If a two component mixture has an absorbance of 0.70 at 350 nm and 0.79 at 400 nm, what are the concentrations of compounds A and B in uM units? Assume a 1 cm cuvette and the following:
Compound A: λ = 350nm, ϵ = 1 x 104 L/mol∙cm; λ = 400nm, ϵ = 5 x 103 L/mol∙cm
Compound B: λ = 350nm, ϵ = 7.5 x 103 L/mol∙cm; λ = 400nm, ϵ = 1.3 x 104 L/mol∙cm
What is the concentration of compound A?
3.4 x 10^-5 M
What is the purpose of the reagent blank in spectrophotometric analysis?
Correct for color contribution of the reagent
Which of the following is the mathematical expression of the relationship between absorbance and transmittance?
A = 2- log %T
Which of the following isolates light within a narrow region of the spectrum?
Monochromator
The bandpass of a spectrophotometer is 10nm. If an instrument is set at 540nm, the wavelengths that are permitted to impinge on the sample will be within what wavelength range?
535-545nm
Which of the following can be done to increase the specificity as well as the sensitivity of spectrophotometric analysis?
Narrow the band pass
Which of the following represents a primary advantage of performing fluorometric over absorption spectroscopic methods of analysis?
Increased specificity and increased sensitivity
Which of following best describes the function of a photomultiplier tube?
It converts radiant energy to electrical energy and amplifies the current significantly
Flurometers 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 is measured in time-delayed fluorescence?
Phosphorescence
Which of the following statements is true about fluorescent polarization?
Plane-polarized light is used for sample excitation.
Which of the following techniques detects unabsorbed, reflected light by a photodetector?
Reflectance photometry
Which of the following is measured in turbidimetry?
Reduction of transmitted light due to scatter
Which of the following is measured in nephelometry?
Scattered light
Which of the following is used in automated bacterial growth monitor?
Turbidimetry
Which of the following statement is true about nephelometry?
The concentration to be measured is directly related to scatter.
Which of the following is associated with chemiluminescence?
Light emission produced due to electron excitation by chemical energy
Which of the following best describes bioluminescence?
Enzymatic oxidation of a substrate produces light emission
Luminescence is caused by which of the following?
Photons emitted while excited electrons drop down
Which of the following statement is true about luminescent assays?
Total light output is proportional to concentration of analyte in reaction dependent assays.
Luciferase assay for ATP is an example of which type of assay?
Luminescence assay
The Bessey method for the determination of alkaline phosphatase takes advantage of substrate p-nitrophenyl forming the colored product p-nitrophenoxide (403nm). To 2.40ml of substrate containing buffer is added 0.10 ml of serum. After 5 minutes, the absorbance at 403nm has changed by 0.550. The molar absorptivity (ϵ) of the product is 18.8 x 103 L/mol ּּּcּm. What is the activity of this enzyme in U/L?
148
The Bessey method for the determination of alkaline phosphatase takes advantage of substrate p-nitrophenyl forming the colored product p-nitrophenoxide (403nm). To 2.40ml of substrate containing buffer is added 0.60 ml of serum. After 5 minutes, the absorbance at 403nm has changed by 0.550. The molar absorptivity (ϵ) of the product is 18.8 x 103 L/mol ּּּcּm. What is the activity of this enzyme in U/L?
29.5
Which of the following statement is NOT true about enzyme?
Enzyme reactions are performed in first-order kinetics with substrate in excess.
Which of the following statements is true about the velocity of an enzyme-catalyzed reaction?
It is related to the substrate concentration at 1/2Vmax.
Fumarate reacts with water to produce malate in mitochondria and such reaction is catalyzed by fumarase. The Km for fumarase is 5μM for fumarate. The fumarate concentration in michoconcdria is 2mM. If the fumarate concnetration drops to 1mM, how would the reaction rate would change?
Decrease slightly
Which of the following is NOT an example of colligative property?
Osmolality
Colligative properties of a solution is affected by which of the following?
The number of molecules
Which of the following is the measure of the number of dissolved particles in solution expressed as osmoles per liter of water?
Osmolarity
Vapor pressure osmometer is not favored by clinical laboratories because of which of the following reasons?
Volatile gases increase the vapor pressure of solvent
What is the osmolaritiy of 0.90% NaCl? (MW of NaCl is 58)
310mOsmol/L
What is the osmolarity of 100mg/dL glucose? (MW of glucose is 180)
5.6mOsmol/L
What is the purpose of using ampholytes in isoelectric focusing?
To establish a pH gradient in the gel
Which of the following is an electrophoretic technique employing a pH gradient that separates molecules with similar isoelectric points?
Isoelectric focusing
A liquid solution of formaldehyde is 37% pure. This solution has specific gravity of 1.037. The molecular weight of formaldehyde is 30.0. To 1.00 ml of this impure stock solution is added quantity sufficient to take the total volume to 500 ml. If 1.00 ml of this solution is added to 4 ml of water in a final reaction, what is the molarity of formaldehyde in this final reaction tube?
5.1mM
I have used a method of electrophoresis to separate a mixture of proteins by size only. I have one band that appears to contain several proteins of very similar size. What electrophoretic procedure would be appropriate to separate this grouping?
Isoelectric focusing
Which of the following methods can NOT be used to separate the free form from the bound in immunochemistry assays?
Electrophoresis
Seperation of the free form from the bound is required for which of the following immunoassays?
ELISA
The following Relative Fluorescent Units (RFU) were derived from a Fluorescent Polarization Immuno Assay (FPIA).
Calibrator Concentration (μg/ml)

RFU
0 --100
5 --78
10 --66
20 --59
40 --52
80 --48

What is most likely the concentration of a patient who had 56 RFU by the same procedure?
30μg/ml
Which of the following statements is NOT true about enzyme multiplied immunoassay (EMIT)?
Enzyme reacts with drug in serum sample.
The enzyme activity measured in the EMIT is the result of the reaction between the substrate and coenzyme with which of the following?
Free labeled antigen
What type of assay is ELISA? Homogeneous or heterogenous assay?
Heterogeneous
What type of bond exists between Ag-Ab?
Non-covalent
Which antibodies are more specific? Monoclonal or polyclonal?
Monoclonal
Which Ab binding is most tight? Polyclonal or monoclonal?
Polyclonal
Name the types Ag-Ab can be classified into
Precipitation, agglutination, complement fixation, serum neutralization, toxin-anoxic
When graphing Ag-Ab, which goes on the X axis?
ANTIGEN
When graphing Ag-Ab, which goes on the Y axis?
ANTIBODY
Which assay is known as "Rocket electrophoresis"
Electroimmunodiffusion (EID)
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