Quizzes

1.) short tandem repeats (str) determined by what?

1.) PCR product size

1.) SYBR green fluorescence is detectable at which stage of the PCR amplification process?

1.) Primer extension

A.) MRSA derives resistance to beta-lactam antibiotics through which mechanism? 1.) Which of the following targets is used to type molds?

A.) Chemical Cleavage 1.) ITS

1.) as the concentration of agarose in the gel (BLANK A), the (BLANK B) the size of DNA that can be resolved on the gel

A.) Increase B.) Smaller

1.) What is a method of signal amplification? 2.) Whats the purpose of an amplification control in PCR? A.) Real-time PCR differs from standard PCR in which way?

1. ) Branched DNA (bDNA) assay 2.) distinguish true from false negatives A.) Real-time PCR is quantitative.

1.) A RNA sample is isolated from peripheral blood cells of a patient. When performing spectrophotomectric analysis to determine the yield of RNA in the sample you find the 1:40 dilution of the 0.5 ml sample gives an OD 260 reading of 0.03125 and an OD 280 reading of 0.01760. What is the total amount of RNA contained in the 0.5 ml sample? 2.) How did you get that?

1.) 25 ug 2.) OD260=0.03125, so then (0.03125 x 40 x 40)/2. This equals out to 25.

1.) When quantifying the amount of genomic DNA in a smaple by spetrophotometry, an OD 260 of 1.0 corresponds to what concentration of DNA? 2.) Why?

1.) 50 ug/ml 2.) The absorptivity constant for DNA is 50ug/ml

1.) RNA collected in denaturant is stable at room temperature for how long? 2.) The quality of RNA isolated from fixed tissue will depend on which factors(2) ? A.) What is the purpose of microdissection of tissue sections in oncology?

1.) 7dy 2.) Type of tissue fixative and length of fixation B.) Enhanced detection of tumor-specific mutations

1.) A translocation in which chromosome pair creates a BCR/ABL1 function gene product associated with CML 2.) When genotyping strains of bacteria by PFGE, what is the minimum number of genetic differences that must be observed between a reference strain and a test strain before it can be determined that the test strain is unrelated to the reference strain?

1.) 9;22 2.) 3

1.) What is TaqMan? A.) What type of PCR starts with an RNA template? B.) PCR reaction that uses more than one primer pair is called C.) what is the correct order of the steps that occur in a standard PCR cycle (3)?

1.) A qPCR probe system A.) Reverse transcriptase PCR B.) Multiplex PCR C.) Denaturation, annealing, and extension

1.) DNA is isolated from a test organism and cut with restriction enzymes. The fragments are ligated to adapters that are complementary to primers that are added to perform two rounds of PCR. The PCR products are separated by gel electrophoresis and analyzed. Which of the following methods is described?

1.) Amplified fragment length polymorphism

1.) Nucleic acids migrate toward which pole in electrophoresis? A.) Which of the following molecules polymerizes to form a support medium through which nucleic acids move?

1.) Anode A.) Polyacrylamide

1.) A PCR assay on DNA isolated from a nasopharyngeal swab was performed, with the following results: amplification using primers to IS481 was positive and using primers to IS1001 was negative. All controls were acceptable. Which of the following organisms was present in this sample?

1.) Bordetella pertussis

1.) Molecular based testing was performed on a nasoparyngeal swab sample taken from a patient. Results reported as positive for IS481 and negative for IS1000. These results indicate the patient's nasopharynx is colonized with:

1.) Bordetella pertussis

1.) Which technique employs the amplification of the signal resulting from probe: target hybridization rather than by amplifying the target or probe

1.) Branched DNA analyses

1.) What is a convenient way to concentrate organisms present in cerebrospinal fluid or urine samples before testing? A.) Which of the following is a genotypic method for typing organisms?

1.) Centrifuge A.) Pulsed-field gel electrophoresis

1.) An (F508del) mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is responsible for causing which of the following diseases? 2.) Li-Fraumeni syndrome, in which affected patients have an increased predisposition to cancer, is caused by a mutation in which of the following genes?

1.) Cystic Fibrosis 2.) TP53 tumor-suppressor gene

1.) What is indicated by CYP2A6? 2.) A patient is tested to determine the number of CGG repeats in the FMR-1 gene by Southern blot. The patient is found to have a band that runs ABOVE the normal control band. Whats is this?

1.) Cytochrome P-450, subfamily IIA, polypeptide 6 2.) The patient has full fragile X mutation.

1.) The Robertsonian translocation may be associated with which genetic disorder? 2.)

1.) Downs syndrome

1.) What method is based on naturally repeated sequences in bacterial DNA? 2.) Which assay has the highest ease of interpretation? 4.) _______ derives resistance to beta-lactam antibiotics through chemical cleavage A.) Which can cause a false-positive result for a target organism?

1.) ERIC 2.) PFGE 4.) MRSA A.) Amplification of nonviable organisms

1.) What can inhibit RNases (3)? A.) Which fixative is the least damaging to nucleic acids?

1.) GITC/reducing agentds/high-salt buffer A.) Buffer formalin

1.) A DNA-specific dye that is used in fluorometry procedures to measure DNA concentration is A.) n procedures for the organic isolation of RNA, guanidinium isothiocyanate (GITC) is added to B.) The most abundant form of RNA in all cells is

1.) Hoechst 33258. A>) inhibit RNases. B.) Ribosomal

1.) A patient is tested for the presence of the factor V Leiden mutation by PCR-RFLP by targeting a G to A mutation in exon 10 of the factor V gene F5. Isolated DNA is amplified by PCR, and the resulting amplicons are cut with MnlI and separated by gel electrophoresis. Two bands are seen in the lane loaded with the patient's sample, one at 153 bp and the other at 67 bp. Controls were acceptable. interpret

1.) Homozygous mutation

1.) A ____ ____ ____ may be used as an amplification control when performing PCR testng for Mycplasma pneuoniae in a bronchoaveolar lavage taken from a human patient. 2.) The type of amplificaiton control is described as

1.) Human actin gene 2.) heterologous intrinsic

1.) Which of the following combinations of molecular-based assays and detected organisms has been approved by the Food and Drug Administration?

1.) Hybridization protection assay for group A streptococci

1.) DNA in solution, after separation from other cellular constituents, is precipitated in which of the following? 2.) What is the first step in DNA isolation from cells in a clinical sample? 3.) what will yield the highest-quality DNA preparation? 4.) whole-blood fraction thats most abundant source of genomic DNA?

1.) Isopropanol 2.) lysis of cells 3.) fresh blood 4.) Buffy coat

1.) The mode of inheritance of mitochondrial DNA is 2.) Term best describes males regarding X linked genes is A.) 2 alleles for a sex linked recessive disease are X and x. The mutant allele is x. What is the percentage of male offspring that would be expected to be affected by the disease from parents who have the following genotypes?

1.) Maternal 2.) hemizygous A.) 50

1.) Genetic diseases is a storage disease in which sulfatides accumulate inside the lysosomes? A.) Fertilization of gametes containing an extra copy of one chromosome will result in what chromosomal abnormality?

1.) Niemann-Pick A.) Trisomy

After performing interphase FISH with X chromosome-specific and Y chromosome-specific alpha satellite probes, it is determined that nuclei in cells from y our phenotypic female exhibit only 1 bright fluorescent spot with the X chromosome specific probe and do not react at all with the Y specific probe. Assuming all controls have worked correctly , what is the most likely diagnosis for this patient

1.) Patient is a female with Turner syndrome

1.) The specificity of the PCR reaction is determined by which of the following components? 2.)

1.) Primers

1.) BLANK are often used during real time PCR to quantitate the formation of specific amplicons during the reaction. 2.) Which system involves the use of 2 distinct probes to generate a fluorescent signal?

1.) Probes 2.) FRET

1.) TaqMan, molecular beacons, and Scorpion-type primers are all used in which of the following procedures? A.) In which of the following nucleic acid-amplification procedures is target nucleic acid labeled with enough signal to be detectable?

1.) Quantitative PCR A.) Hybrid capture assay

1.) Reverse transcriptase would best be described as a 2.) A metaphase chromosome with primary constriction that gives the chromosome defined short and long arm is? A.) which is considered an epigenetic modification of DNA

1.) RNA dependent DNA poymerase 2.) submetacentric A.) methylation of CpG islands in the promoter region of the gene

1.) A PCR assay using primers specific for the autolysin (lytA) gene was performed on a sputum specimen from a 10-year-old girl. The specimen was positive, and all controls were acceptable. Which of the following is the best interpretation of these results?

1.) S. pneumoniae is present, but the clinical significance is questionable.

1.) Which of the following can be used to detect the location of DNA bands in a gel after electrophoresis? 2.) In order to monitor the progress of electrophoresis, which of the following is added to a sample that does not associate with DNA and runs ahead of the smallest fragments in the sample?

1.) SYBR 2.) Bromphenol Blue

1.) The fluorescent dye that exhibits the greatest sensitivity for quantization of DNA is 2.)) What is used to extract DNA from cells 3.) How many volumes of ethanol are added to 1 volume of DNA: salt solution to cause the DNA to precipitate?

1.) SYBR green 2.) Chelex 100 resin 3.) 2

1.) Which of the following is an important characteristic of a target sequence for the molecular detection of a microorganism?

1.) The sequence must be unique to the target organism.

1.) In the interpretation of pulsed-field gel electrophoresis patterns, one genetic difference can result in how many fragment differences?

1.) Two-Three

1.) Genetic analysis of four generations of a family reveals that about 50% of the males in the family are affected by a mutation and about 50% of the females are carriers of the mutation that affects the males. What type of inheritance pattern is seen in this family? 2.) Sex-linked disorders involve which of the following chromosomes?

1.) X-linked recessive 2.) X

1.) Which probe is most often used to detect trisomy 21 by interphase FISH? A.) What is a solution hybridization method for the detection of nucleic acid protein interactions

1.) alpha satellite DNA probe A.) gel mobility shift assay

1.) Which locus is used to identify the gender of the individual whom a DNA sample is obtained? A.) A molecular based test commonly used in testing donors and recipients prior to organ transplantation is?

1.) amelogenin A.) sequence specific PCR

1.) What is the most critical step in determining the specificity of a PCR reaction 2.) Denature DNA during PCR reaction refers to breaking A.) Which reagent generates a signal during the annealing stage of a quantitative real time PCR reaction

1.) annealing temperature 2.) hydrogen bonds between nitrogenous bases in base paired nucleotides A.) molecular beacon

1.)According to Tenover rules, what is the relationship between TWO organisms with THREE PFGE band differences? 2.) What characteristic of parasites complicates molecular testing? A.) qPCR with multiple primer pairs and probes describes which of the following assays?

1.) closely related. 2.) Resistance to disruption and lysis A.) BioFire

1.) Which what PCR controls ensures that the reaction mix is not contaminated with amplicons from a previous PCR procedure and must not have a PCR product detected in order to be valid? 2.) PCR controls ensures that the enzyme is active, the buffer is optimal, and the primers are priming the correct target sequence and must have a PCR product detected in order to be valid?

1.) contamination control 2.) positive control

1.) A common use for pulsed field gel electrophoresis is A.) Monitoring the load of HIV circulating in a patient's plasma would best be accomplished using which method?

1.) epidemiological typing of bacterial strains A.) NABSA

1.) Intervening sequences are found in 2.) During the G2 phase of the cell cycle, the DNA content of a cell is 3.) Which nucleotide pair has a high frequency of mutation in human chromosomal DNA

1.) hetranuclear RNA 2.) tetraploid 3.) CG

1.) Klenow fragments of E. coli DNA polymerase I is used A.) Which condition (temp and salt conc.) has the highest stringency for washing a southern blot after hybridization has been completed?

1.) label DNA probe by random primer labeling 2.) High temp/low salt

1.) What will be observed in a PCR test of a true-negative sample for the sample, positive, negative, and amplification controls, respectively? 2.) A positive control is added (spiked) into a test specimen. The test results of the specimen alone and the spiked mixture are negative. What does this most likely indicate?

1.) negative; positive; negative; positive 2.) The specimen contains an inhibitor.

1.) A variation of a standard PCR reaction that can increase the sensitivity and specificity of a low copy number target in a patient sample is known as A.) A PCR reaction in which 4 different sets of primers are used to simultaneously amplify 4 distinct loci in the same reaction tube is known as

1.) nested PCR A.) multiplex PCR reaction

1.) Which statement is true concerning molecular based paternity testing A.) DNA sequencing of hypervariable regions I and II is used to

1.) paternity index is calculated for the alleged father using all loci tested, even if one of the loci does not match the child A.) detection of polymorphisms in human mitochondrial DAN

1.) The molecular based diagnostic test for Mycobacterium tuberculosis uses _____ as the target. 2.) Primers are made to be specific for which subunit of question 1? A.) DNA based testing for the presnece of MRSA uses PCR with primers specific for which gene?

1.) rRNA 2.) 165 A.) mecA

1.) When MRSA chemical cleaves, what does this result in? A.) HIV genotyping is performed for which of the following reasons? B.) Which of the following methods that are used to determine the HIV viral load in a newly diagnosed patient uses signal amplification? C.) Which of the following genes is the target in molecular-based assays that are used to quantify the amount of HIV in a patient?

1.) resistance to beta-lactam antibiotics A.) Monitor development of antiretroviral drug resistance B.) bDNA C.) gag

1.) attaching MULTIPLE PROBES to a nitrocellulose membrane and then hybridizing a SINGLE LABELED PATIENT sample to the MULTIPLE PROBES is the methodology for what? 2.) An RFLP is most likely detected using what method

1.) reverse dot blot 2.) Southern Blot

1.) Method is best suited to screen for mutations in a gene having multiple possible mutations? A.) Methylation of cytosine residues is involved in the alteration of gene expression in a number of cancers. Which sequencing technique is best suited to determine if methylation of cytosine residues has taken place in the promoter region of a given gene?

1.) single stranded conformational polymophism A.) bisulfite sequencing

1.) Best method to rule out the possibility of genomic DNA giving a false positive result in a RT PCR reaction? A.) What is the purpose of the enzyme uracil N glycolase in a molecular diagnostics laboratory

1.) upstream and downstream primers that span an exon-intron-exon region of the target A.) remove an previously generated amplicons containing dUTP from PCR reactions

1.) Which of the following genes is a target in molecular-based assays and confers resistance to vancomycin in the enterococci? A.) When a typing method is repeated and the results are the same each time, the method has high B.) The ability of a typing method to distinguish between unrelated strains describes which of the following criteria?

1.) vanA A.) reproducibility. B.) Discriminatory power

When processing a whole-blood specimen, it is important to remove ________because it can inhibit DNA polymerase and thus may prevent the amplification of nucleic acid in the sample, resulting in a false-negative PCR result.

hemoglobin

A PCR assay is performed, and the results are being analyzed. The positive control has a band at the expected size, the negative template control has a band at the same size as the positive control, the contamination control has no band, and the amplification control has a band of expected size. All of the patient samples that were run had a band the same size as the band seen in the positive and negative template control wells. Why is this unacceptable?

negative template control should not have a band.

A PCR based assay performed to determine the clonality of B cells in a patient using a forward primer specific for the innermost framework region and a reverse primer complimentary to the joining region (of the immunoglobulin heavy chain). When run on an agarose gel containing ethidium bromide, the patient sample exhibits a smear of staining over a wide range in the patient sample lane along with one distinct band approximately a third of the way down from the sample loading well. Assuming all controls worked properly for the assay, what is your interpretation of the results for this patient?

patient has a monoclonal population of b cells

A molecular technologist has run a vertical gel. While analyzing the gel, the technologist notices that the bands in the outer lanes did not run as far as similar-size bands in the inner lanes, resulting in the bands looking like a smile on the gel. What is the explanation for this?

temperature across the gel was not constant, so the inner wells were warmer