35. Molecular Diagnostic Techniques in Hematopathology

Question 1

1. All assays using nucleic acid probes rely on which of the following principles ?

a. DNA is different in every cell of a particular individual.

b. A probe hybridizes to its complementary sequence

c.Heat or high pHconverts single-stranded to double-stranded DNA.

d. Restriction endonucleases cut DNA into 500 base pair lengths RNA.

e.Probes bind to RNA rather than DNA.

Answer 1

b. A probe hybridizes to its complementary sequence

Question 2

2. To convert double-stranded DNA into two single strands, which of the following procedures is used?

a.Heat DNA to 95℃.
b.Expose the DNA to an alkaline pH.
c.Either of the above
d.Neither of the above

Answer 2

c.Either of the above

Question 3

3. The following are steps in the Southern blot procedure except:

a.Agarose gel electrophoresis
b.Cut DNA with restriction endonuclease.
c.Synthesize DNA at 72℃.
d.DNA extraction

Answer 3

c.Synthesize DNA at 72℃.

Question 4

4. Which of the following chemicals is used to stain DNA in agarose gels?
   a.EcoR1
   b.Ethidium bromide
   c.Ethanol
   d.Formalin

Answer 4

b.Ethidium bromide

Question 5

5.Which of the following substances is most likely to be-come degraded in a patient sample stored at room tem-perature overnight?
a.Protein
b.Lipid
c.Amino acid
d.DNA
e.RNA

Answer 5

c.Amino acid

Question 6

6.Which of the following probes would be most appropriate for an assay in which you want to target the following
DNA sequence, 5’-AAAGGGTCTCTCTTTTGGG-3’?

a.5’-AAACCCCTCTCTCAAAGGG-3’
b.5’-TTTCCCAGAGAGAAAACCC-3’
c.5’-CCCAAAAGAGAGACCCTTT-3’
d.5’-GGGAAACTCTCTCCCCAAA-3’

Answer 6

c.5’-CCCAAAAGAGAGACCCTTT-3’

Question 7

7.Which statement is true about the polymerase chain re-action(PCR)?

a. It is a method for amplifying a particular segment of DNA.
b.The DNA polymerase that is used as a reagent in this assay cuts DNA into many fragments.
c. It is laor intensive and expensive compared with Southern blot analysis.
d. The assay does not require use of any nucleic acid probes.

Answer 7

a. It is a method for amplifying a particular segment of DNA.

Question 8

8.In addition to patient samples, every PCR run includes a control sample containing al of the reagents necessary for DNA amplification except for target DNA.Why is this control sample included?
a. To ensure that no reagent was left out of the reaction
b. To ensure that there are no inhibitors of DNA amplifi-cation
c. To show that PCR products can be generated
d. To check for contamination by extraneous DNA

Answer 8

d. To check for contamination by extraneous DNA

Question 9

9. Which reagent is most critical for designing a real-time PCR assay that measures BCR/ABLI as opposed to PML/RARA translocation?
   a.primers
   b. DNA polymerase
   c.Buffer
   d.Magnesium chloride
   e.Deoxyribonucleotides

Answer 9

a.primers

Question 10

10.Which concept best distinguishes polymerase chain reaction (PCR) from reverse transcriptase PCR (RT-PCR)?
a.The forward versus reverse direction of strand synthesi
b. Addition of deoxyribonucleotides versus ribonu-cleotides to the reaction
c. Generation of a DNA product versus an RNA produc
d. Patient DNA versus RNA is the substrate for the reaction
e.Addition of DNA polymerase versus RNA polymeras to the reaction

Answer 10

d. Patient DNA versus RNA is the substrate for the reaction

Question 11

11.Which is true of the in situ hybridization procedure for analyzing paraffin tissue sections immobilized on glass slides?
a. It localizes DNA or RNA in the context of histologic and cytologic features.
b. It detects restriction fragment length polymorphisms.
c. It amplifies sequences up to 5000 nucleotides in length.
d.All of the above

Answer 11

a. It localizes DNA or RNA in the context of histologic and cytologic features.

Question 12

12. In situ hybridization is best used to:
    a.Localize beta-globin protein in a tissue section.
    b. Detect a mutation in the JAK2 gene.
    c.Localize Epstein-Barr virus to malignant cells.
    d. Match a suspect to a sample of blood found at a crime scene.
    e.Find clonal rearrangement of the IGH gene.

Answer 12

c.Localize Epstein-Barr virus to malignant cells.

Question 13

13. Which assay is most sensitive for detecting minimal residual disease in a patient treated for chronic myeloge-nous leukemia?
    a.Karyotype
    b.Reverse transcriptase polymerase chain reaction
    c. Southem blot analysis
    d.Light microscopy
    e.DNA sequencing

Answer 13

b.Reverse transcriptase polymerase chain reaction

Question 14

14.Molecular probes can be used to speciate infectious agents in patient samples primarily because:
a. Probes targeting pathogens never cross-react with hu.man genomic DNA.
b.Drug resistance factors differ in each species.
c.Each species shares unique sequences that differ from those of other species.
d. Real-time PCR allows quantitation of target se-quences.
e.Dividing organisms often acquire genetic mutations.

Answer 14

c.Each species shares unique sequences that differ from those of other species.

Question 15

15.Which assay is most appropriate for routine clinical detection of the point mutation responsible for sickle cell anemia?
a. In situ hybridization
b. Fluorescence in situ hybridization
c.Gene expression profile array
d.Polymerase chain reaction with melt-curve analysis

Answer 15

d.Polymerase chain reaction with melt-curve analysis