Module 4 FISH Flashcards
Which of the following counterstain dyes should be used to counterstain the cells with
Spectrum Green /Spectrum Red dual color signals?
A. DAPI
B. Propidium iodine C. Ethidium bromide D. Acridine orange
A
DAPI is a _________ counterstain.
A. green B. yellow C. blue D. red
C
The process of fluorescence in situ hybridization is used to:
A. Structure a complete karyotype. B. Show the repair of DNA sequences after denaturation. C. Visualize specific sequence of DNA with a fluorochrome. D. Label colonies of cultured cells.
C
Which of the following is critical to the success of a FISH procedure?
A. Probe can only be labeled with the fluorochrome. B. Temperature of the denature solution. C. Slides should be aged at 60oC for at least overnight. D. The FISH signal should be detected immediately after the hybridization.
B
Formamide is used in the FISH procedure for which of the following purposes:
A. To be used to rinse off excess salt from the slides. B. To modify a DNA probe so it can be detected by a fluorochrome. C. To artificially age the slide. D. To lower the DNA melting point.
D
The purpose of the post hybridization wash is to:
A. Enhance the binding of the fluorochrome B. Serve as a pretreatment for probe labeling C. Remove unbound probe from the slide D. All of the above
C
Which of the following is true about slide preparation for FISH?
A. Slides should be kept at room conditions.
B. Slides should be treated overnight in a 90oC oven. C. Slides should be prepared 1 week in advance and stored in the refrigerator. D. Slides should be protected from ultraviolet light
A
When analyzing a sample stained with a FISH probe, the technologist notices a high amount of nonspecific cross-hybridization. Which of the following is the most likely cause?
A. The counterstain was not added. B. The wash stringency was too low. C. The manufacturer produced a poor probe set. D. The denaturation process did not work.
B
When using the Applied Imaging system to capture the FISH image, which program should be chosen?
A. Fluorescent
B. Probe C. RXFISH D. MFISH
B
Which of the following statements is true about directly labeled probes?
A. Should be counterstained only with DAPI.
B. Require amplification of the probe signal. C. Exposure to light should be avoided. D. Denaturation of the probe is not necessary.
C
Which of the following is critical to the success of a FISH procedure?
A. Probe can only be labeled with the biotin hapten B. Temperature of the denaturation solution C. Slides should be aged at 60oC for at least one week D. The FISH signal should be detected immediately after the hybridization procedure.
B
The hapten digoxigenin is used in the FISH procedure for which of the following purposes?
A. To provide a binding site for fluorochromes, thereby allowing probe detection.
B. To artificially age the slide C. To provide a fluorescent signal that can be seen with a fluorescent microscope D. To be used to rinse off excess salt and formamide from the slide.
A
Formamide is used in the FISH for which of the following purposes?
A. To be used to rinse off excess salt from the slide B. To modify a DNA probe so it can be detected by a fluorochrome C. To artificially age the slide D. To denature the DNA prior to hybridization
D
The intensity of probe signal and the amount of background is dependent on the stringency level of which of the following chemicals?
A. SSC
B. Digoxigenin C. Phosphate buffer D. Propidium iodide
A
The M-FISH procedure makes use of combinatorial labeling in order to uniquely label all chromosomes human chromosomes. Which of the following represents the correct mathematical equation for determining the number of combinations based on the number of fluorochromes (n) available?
A. # of Combinations = (2n-1) B. # of Combinations = (n-1/2)(2) C. # of Combinations = n-12 D. # of Combinations = (2n)
A
What is the maximum number of color combinations that can be obtained from 5 fluorochromes?
A. 7 B. 15 C. 31 D. 63
C
DAPI is a:
A. red counterstain B. high stringency wash C. low stringency wash D. blue counterstain
D
Propidium iodide is a:
A. blue counterstain B. red counterstain C. high stringency wash D. low stringency wash
B
The purpose of the post-hybridization wash is to:
A. Enhance the binding of the fluorochrome B. Serve as a pretreatment for probe labeling C. Remove unbound probe from the slide D. Enhance RNase removal from the slide
C
Why are whole chromosome probes and FISH not suitable at this time for detection of mosaic trisomies in interphase nuclei?
A. The probes cannot penetrate through the interphase nuclei to the DNA. B. The domains can overlap each other in a two dimensional field. C. More than two signals appear routinely in more than 50% of normal cells.
B
Interphase cytogenetic analysis using chromosome-specific probes is most useful for:
A. Detecting mosaicism B. Detecting chromosomal rearrangements C. Providing a rapid diagnosis for a suspected numerical chromosome abnormality. D. Detecting single gene disorders
C
Which of the following IS NOT an advantage of FISH diagnostics concerning interphase testing?
A. Is more informative than chromosome karyotyping
B. Can rapidly detect sex chromosomes or aneuploidy of chromosomes. C. Requires no culture. D. Requires only simple microscope analysis.
A
In situ hybridization was originally introduced as a method which detects:
A. The abnormal rearrangement of genes B. Highly repetitive nucleic acid sequences C. Highly repetitive genes D. Highly unusual nucleic acid sequences
B
The technologist responsible for the FISH procedure has repeated problems with poor chromosome spreading due to cytoplasm remaining around the chromosomes. How will this cytoplasm affect the FISH procedure?
A. Hybridization of the probe to its target DNA is unaffected by cytoplasm. B. Detection of the probe with appropriate fluorochrome is unaffected by cytoplasm. C. When detected with the appropriate fluorochrome there will be a decrease in background signal. D. There will be a significant reduction or total lack of hybridization of the probe to its target DNA.
D
