CHEM01 - Instrumentation and Methods

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  1. The measure of oxygen in blood by means of the Clark O2 electrode involves which of the following?

    A) Measurement of current as O2 is reduced by a platinum electrode.
    B) Measurement of current resulting from an increase of free silver ions formed by O2 oxidation of silver metal
    C) Ionselectiveelectrode sensitive to free silver ions generated by O2 oxidation of silver metal
    D) Oxidation of H2O to H2O2 followed by a peroxidasecoupledmeasurement of the H2O2.
    A) Measurement of current as O2 is reduced by a platinum electrode.
    (this multiple choice question has been scrambled)
  2. Measurement of CO2 in blood by means of the Severinghaus pCO2 electrode is best described by which ofthe following?

    A) Change in pH as CO2 reacts with a bicarbonate/carbonic acid buffer after passing through asemipermeable membrane
    B) Biosensor that measures H2CO3 formed when carbonic anhydrase combines CO2 and H2O.
    C) Measurement of bicarbonate by an HCO3- ion selective electrode
    D) Measurement of pH and calculation of pCO2 from the linear relationship between pCO2 and pH insolution
    A) Change in pH as CO2 reacts with a bicarbonate/carbonic acid buffer after passing through asemipermeable membrane
    (this multiple choice question has been scrambled)
  3. Gas chromatography would be best used for measurement of:

    A) cancer antigens
    B) serum proteins
    C) drugs of abuse
    D) carbohydrates
    C) drugs of abuse
    (this multiple choice question has been scrambled)
  4. An ionselective electrode that incorporates the antibiotic valinomycin into its polymer membrane is sufficiently specific for the measurement of

    A) None of these
    B) Ca++
    C) Li+
    D) Na+
    E) K+
    E) K+
    (this multiple choice question has been scrambled)
  5. Which of the following isolates light within a narrow region of the spectrum?

    A) Monochromator
    B) Photomultiplier
    C) Detector
    D) Photovoltaic cell
    A) Monochromator
    (this multiple choice question has been scrambled)
  6. In spectrophotometry, which of the following is a mathematical expression of the relationship between absorbance and transmittance?

    A) A=abc (or A=Ecl)
    B) Au/Cu=As/Cs
    C) A=log%T
    D) A=2log%T
    D) A=2log%T
    (this multiple choice question has been scrambled)
  7. (T/F) Freezing point is decreased in direct proportion to the concentration of dissolved particles of a solution.
    True
  8. (T/F) The hexokinase method for detection of glucose is a coupled enzyme reaction and measures the increase inabsorption of NADPH at 340nm.
    True
  9. Atomic Absorption Spectrophotometry is most commonly used for analysis of

    A) porphyrins
    B) enzyme activators
    C) vitamins
    D) heavy metals
    D) heavy metals
    (this multiple choice question has been scrambled)
  10. The purpose of the sample blank in spectrophotometric measurement is to 

    A) to determine the zero point of the calibration curve
    B) compensate for reagent color changes
    C) prevent colors inherent in the sample from contributing to measurement of an analyte
    D) to minimize crossreactivity
    C) prevent colors inherent in the sample from contributing to measurement of an analyte
    (this multiple choice question has been scrambled)
  11. The source of monochromatic light in an atomic asorption spectrophotometer is a

    A) flame
    B) hollow cathode lamp
    C) heated graphite tube
    D) argon laser
    B) hollow cathode lamp
    (this multiple choice question has been scrambled)
  12. (T/F) The hook effect, a disadvantage in sandwich immunoassays, is due to antigen excess in a sample. This can be detected and remedied by diluting the sample and reassaying.
    True
  13. Homogeneous immunoassays are so named because

    A) There is no need to separate bound from free label
    B) They detect a single class of compounds.
    C) Several different molecules can be detected in a single assay
    D) They only use a single reagent
    A) There is no need to separate bound from free label
    (this multiple choice question has been scrambled)
  14. A competitive inhibitor of an enzyme acts by

    A) combining with the substrate
    B) binding to the enzyme:substrate complex
    C) binding to the active site of the enzyme
    D) binding to a site on the enzyme distinct from the active site
    C) binding to the active site of the enzyme
    (this multiple choice question has been scrambled)
  15. Advantages of the "sandwich" (noncompetitive,twosite,immunometric) immunoassay include all of the following EXCEPT

    A) Can have higher specificity
    B) Can use higher antibody concentrations to drive reaction kinetics
    C) Can measure both small molecules (e.g., steroids) and proteins
    D) Have a greater dynamic range
    C) Can measure both small molecules (e.g., steroids) and proteins
    (this multiple choice question has been scrambled)
  16. An example of an clinical assay that might be done by affinity chromatography is

    A) quantitation of serum IgG
    B) measurement of glycated hemoglobin
    C) separation of abnormal hemoglobin species
    D) fractionation of CK isoenzymes
    B) measurement of glycated hemoglobin
    (this multiple choice question has been scrambled)
  17. You calibrate a spectrophotometric assay for albumin with a saline blank and a 4.3 gm/dL calibrator. The absorbances from these the reactions are blank: 0.050 and calibrator: 0.480. Your QC sample reads 0.510. Calculate its concentration.

    A) 5.1 gm/dL
    B) 4.8 gm/dL
    C) 4.6 gm/dL
    d) None of the above
    c) Cannot determine with available data
    C) 4.6 gm/dL
    (this multiple choice question has been scrambled)
  18. The Beer(Lambert)law can be stated as:

    A) A = 2log(%T)
    B) A = abc (or A=Ecl)
    C) %T = I/I(sub 0) x 100
    d) None of the above
    A) A = 2log(%T)
    (this multiple choice question has been scrambled)
  19. In gasliquidchromatography or HPLC, compounds are characterized by their

    A) peak area or height
    B) relative retention time
    C) signal:noise ratio
    D) Rf value
    B) relative retention time
    (this multiple choice question has been scrambled)
  20. Clinically important (diagnostically) enzyme classes include the following EXCEPT:

    A) Hydrolases
    B) Isomerases
    C) Transferase
    D) Oxidoreductases
    B) Isomerases
    (this multiple choice question has been scrambled)
  21. In an enzyme reaction, the reaction rate is linear over time when:
    [E] = Enzyme concentration
    [S] = Substrate concentration

    A) Rarely
    B) [E] ~ [S]
    C) [E] greatly exceeds [S]
    D) Always
    E) [S] greatly exceeds [E]
    E) [S] greatly exceeds [E]
    (this multiple choice question has been scrambled)
  22. +Multiple forms of an enzyme derived from different genes
    +Multiple forms of an enzyme derived from post translational modification

    -Isobars
    -Isoforms
    -Isoenzymes
    -Isotopes
    • Multiple forms of an enzyme derived from different genes: Isoenzymes
    • Multiple forms of an enzyme derived from post translational modification: Isoforms
  23. Most clinically important enzymes are reported in what units?

    A) katal
    B) pmol
    C) IU
    D) ng
    C) IU
    (this multiple choice question has been scrambled)
  24. For each of the following analytes or analyte classes, choose the chromatographic technique that would be most useful in separation. No technique is used twice.

    +Abnormal hemoglobins
    +Drugs of Abuse
    +Hemoglobin A1c
    +Immunosuppressant drugs

    -Size-exclusion
    -HPLC
    -Affinity
    -Ion-exchange
    -Gas-liquid
    • Abnormal hemoglobins: Ion-exchange
    • Drugs of Abuse: Gas-Liquid
    • Hemoglobin A1c: Affinity
    • Immunosuppresent drugs: Ion-exchange
  25. For each of the following, select the technique most commonly used in its measurement

    +Blood pCO2
    +Blood pO2
    +Serum sodium
    +Sweat chloride

    -Coulometry
    -Potentiometry
    -Voltammetry
    -Amperometry
    -Atomic absorption
    • Blood pCO2: Potentiometry
    • Blood pO2: Amperometry
    • Serum sodium: Potentiometry
    • Sweat chloride: Coulometry
  26. Vapor pressure osmometry is not recommended for use in the clinical lab because:

    A) it is inherently less accurate than freezing point methods
    B) it gives misleadingresults when used for alcohol surrogate testing
    C) it is affected by ambient humidity
    D) it is valid only for nonproteinaceoussamples, e.g., urine.
    B) it gives misleadingresults when used for alcohol surrogate testing
    (this multiple choice question has been scrambled)
  27. The relative retention time for a gas-liquid chromatographic peak is based upon its position relative to

    A) the injection point
    B) the largest peak
    C) end of the run
    D) the internal standard
    D) the internal standard
    (this multiple choice question has been scrambled)
  28. (T/F) Radioimmunoassay (RIA) is seldom used currently due to health and safety issues requiring onerous handling and disposal requirements.
    False
  29. (T/F) The LineweaverBurkplot graphs 1/[S] vs 1/Vo and allows determination of Vmax, Km.
    • [S] = substrate concentration, [E] = enzyme concentration
    • Vo = reaction velocity, Vmax = maximal velocity, Km = Michaelis constant
    • True
  30. Enzymes are measured in plasma/serum primarily as a means of assessing

    A) the patient's current metabolic status
    B) the source of increased or decreased metabolites in plasma/serum
    C) damage to specific tissues
    D) None of these
    E) the presence of inherited enzyme deficiencies or excesses
    A) the patient's current metabolic status
    (this multiple choice question has been scrambled)
  31. For each of the following photometric techniques, match with the terms that describe:
    1) how the detected light wavelength compares to the instrument monochromator output and
    2) whether the photodetector is in line with the sample and light source (on axis) or at some angle to it (off axis)

    +(Spectro)photometry
    +Fluorimetry
    +Chemiluminescence
    +Nephelometry
    +Turbidimetry

    -shorter wavelength, on axis
    -shorter wavelength, on axis
    -same wavelength, off axis
    -same wavelength, on axis
    -longer wavelength, on axis
    -longer wavelength, on axis
    -no light source, no axis
    • (Spectro)photometry: same wavelength, on axis
    • Fluorimetry: longer wavelength, off axis
    • Chemiluminescence: no light source, no axis
    • Nephelometry: same wavelength, off axis
    • Turbidimetry: same wavelength, on axis
  32. The most common detection label for automated immunoassay is currently

    A) chemiluminescence
    B) fluorescence polarization
    C) enzyme
    D) fluorescence
    A) chemiluminescence
    (this multiple choice question has been scrambled)
  33. An advantage of competitive immunoassay is that

    A) it usually has a very wide dynamic range
    B) does not require separation of bound and free
    C) both large and small molecules can be measured
    d) none of the above, noncompetitveassays are always advantageous
    C) both large and small molecules can be measured
    (this multiple choice question has been scrambled)
  34. The presence of heterophile antibodies or HAMA in a sample would be most likely to cause a problem in which assay?

    A) Lactate deydrogenase
    B) IgG
    C) serum hCG
    D) Glucose
    C) serum hCG
    (this multiple choice question has been scrambled)

Card Set Information

Author:
victimsofadown
ID:
327301
Filename:
CHEM01 - Instrumentation and Methods
Updated:
2017-01-10 05:13:03
Tags:
CHEM01 Instrumentation Methods
Folders:
TESTS,CHEM
Description:
CHEM01 - Instrumentation and Methods
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