Ch. 9 Molecular Diagnostics

1. During replication the "parent" strand of DNA

serves which purpose?

a. It is completely excised by exonuclease enzymes

when replication of the strand is complete

b. It has a sequence that is complementary to the

daughter strand that is being replicated

c. It is also referred to as the lagging strand

d. It will be copied by a DNA polymerase to form

two new daughter DNA strands

b. It has a sequence that is complementary to the

daughter strand that is being replicated

2. Which of the following are forms of nucleic acids?

a. Nucleosides

b. DNA or RNA

c. Base pairs

d. Trinucleotide sequences

b. DNA or RNA

3. The central dogma speaks to the function of the

molecular components of DNA and states that:

a. The main function of genes is to store and transmit

genetic information

b. There are specific nucleotide triplets that code for

specific amino acids

c. Genes are perpetuated as sequences of nucleic

acid, but function by being expressed in the form

of protein

d. All sequences of DNA in the human genome will

result in the production of RNAs

c. Genes are perpetuated as sequences of nucleic

acid, but function by being expressed in the form

of protein

4. An exon is defined as:

a. A region of DNA present in a mature strand of

mRNA and can be translated into protein

b. A region of DNA that is recognized by RNA polymerase

to start transcription

c. A region of DNA that is transcribed then removed

from mRNA by excision and is not translated into

protein

d. A region of DNA comprising three base pairs that

signal for termination of replication

a. A region of DNA present in a mature strand of

mRNA and can be translated into protein

5. During the replication process the addition of bases

occurs:

a. At the telomeric end of a DNA strand

b. In the 30 to 50 direction

c. In the 50 to 30 direction

d. In both the 50 to 30 and 30 to 50 directions

c. In the 50 to 30 direction

6. Transfer RNA (tRNA):

a. Is a gene silencing RNA used in cancer research

b. Is a macromolecular complex delivered from the

nucleus by ribosomal RNA

c. Contains the codon sequence that synthesizes an

amino acid

d. Contains the anticodon region that binds to

mRNA codon in the ribosome

d. Contains the anticodon region that binds to

mRNA codon in the ribosome

7. Which one of the following statements concerning

mitochondrial DNA (mtDNA) is incorrect?

a. Pseudogenes are small pieces of nuclear DNA that

share significant homology with mtDNA

b. mtDNA is circular and contains approximately

16,500 base pairs

c. mtDNA is inherited from the mother because

only ova contain mitochondria

d. Follows mendelian inheritance patterns

d. Follows mendelian inheritance patterns

8. The enzyme ligase joins the Okazaki fragments of the

__________________.

a. Template strand

b. Lagging strand

c. Leading strand

d. Primer fragments

b. Lagging strand

9. How does ribonucleic acid (RNA) differ from deoxyribonucleic

acid (DNA)?

a. RNA has a uracil and DNA has a thymine

b. RNA does not contain nucleotides and

DNA does

c. DNA resides in the cytoplasm of the cell andRNA

is in the nucleus

d. DNA has a messenger form and RNA does not

a. RNA has a uracil and DNA has a thymine

10. The chromosomes in a eukaryotic cell:

a. Are in their most compact state and appear as

chromatin arms joined at the center during the

cell division stage called metaphase

b. Contain genomic regions that are rich in genes,

less compactly organized, and termed

heterochromatin

c. Contain two specialized regions of euchromatin,

telomeres, and centromeres

d. Are highly ordered structures of a single RNA

molecule, compacted many times with the aid

of structural RNA-binding proteins

a. Are in their most compact state and appear as

chromatin arms joined at the center during the

cell division stage called metaphase

11. Which of the following is a description of restriction

endonucleases?

a. A family of bacteria from which endonuclease

that cuts DNA into fragments is produced

b. Only able to digest specific genes on specific chromosomes

with their endonuclease action

c. Enzymes that specifically degrade DNA in nucleic

acid mixtures when plasmids are present

d. Enzymes produced by bacteria to prevent invasion

and replication of foreign DNA in their bacterial

genome

d. Enzymes produced by bacteria to prevent invasion

and replication of foreign DNA in their bacterial

genome

12. Which enzyme catalyzes DNA replication?

a. Endonuclease

b. Ligase

c. Polymerase

d. Reverse transcriptase

c. Polymerase

13. Which of the following is a block of specific sequence

variants that are inherited together?

a. Allele

b. Haplotype

c. Locus

d. Polymorphism

b. Haplotype

14. Messenger RNA (mRNA) is produced in the

_____________.

a. Golgi

b. Mitochondria

c. Nucleus

d. Ribosomes

c. Nucleus

15. In the organic liquid phase (phenol-chloroform)

DNA extraction procedure, proteins are precipitated

out of solution:

a. In the aqueous phase

b. As a pellet on the filter

c. In the organic phase

d. On the silica-based gel

c. In the organic phase

16. The purity of an extract of nucleic acid can be determined

by which of the following?

a. Measuring absorbances at 260 nm and 280 nm

and dividing A260 by A280

b. Measuring the bands on an agarose gel

c. Measuring absorbances at 260 nm and 280 nm

and subtracting A280 from A260 and then multiplying

the result by a dilution factor

d. Multiplying the concentration of the nucleic acid

by the dilution factor

a. Measuring absorbances at 260 nm and 280 nm

and dividing A260 by A280

17. Solid-phase DNA extraction procedures are more

commonly used in a clinical laboratory because:

a. They can be coupled with a gas chromatograph

linked to a mass spectrometer

b. They performbest when a large volume of sample

is submitted for DNA extraction

c. They are adaptable to automation

d. They involve organic solvents that are easily

found in a laboratory

c. They are adaptable to automation

18. The rate of DNA migration in a gel electrophoresis

depends primarily on the ____________.

a. Buffer temperature

b. Pore size of the gel

c. Shape of the DNA molecule

d. Size of the genomic DNA

d. Size of the genomic DNA

19. Signal amplification differs from target amplification

when designing protocols for identification of

nucleic acids. Which of the following is an example

of a signal amplification technique?

a. Branched-chain DNA detection

b. Ligase chain reaction

c. Polymerase chain reaction

d. Reverse-transcriptase PCR

a. Branched-chain DNA detection

20. Identify the correct sequence of events for a polymerase

chain reaction (PCR) cycle.

a. Anneal, extend, and denature

b. Denature, anneal, and extend

c. Extend, anneal, and denature

d. Extend, denature, and anneal

b. Denature, anneal, and extend

21. When RNA is to be used in a PCR amplification

procedure, what is the first step that must be

performed?

a. RNA cannot be used in a PCR reaction because it

will disintegrate during the denaturation step

b. RNA must be denatured to form single strands to

allow for the annealing of primers

c. A reverse-transcription procedure must be performed

to form cDNA

d. RNA must first be treated with RNases to remove

interfering substances from the target

c. A reverse-transcription procedure must be performed

to form cDNA

22. In the PCR, a _____________ initiates extension of

the sequence of interest by allowing Taq polymerase

to begin adding nucleotides to single-stranded DNA.

a. Probe

b. Ligase

c. Promoter

d. Primer

d. Primer

23. When performing a PCR procedure, which is the

most important control to run to check for the presence

of amplicons?

a. Blank control

b. dTTP control

c. Control

d. Oligo dT control

a. Blank control

24. The process of transferring the digestedDNAout of a

gel after electrophoresis and onto a nylon membrane

is referred to as:

a. Hybridization blotting

b. Northern blotting

c. Southern blotting

d. Western blotting

c. Southern blotting

25. In a real-time PCR assay, which probe type is used in

conjunction with fluorescence resonance energy

transfer (FRET) on the formation of a duplex?

a. Hybridization

b. Hydrolysis

c. Hexamere

d. Primer

a. Hybridization

26. The increase in quantifiable signal observed early in a

real-time PCR run depends on which of the

following?

a. The wavelength of the fluorescent dye in the

reaction

b. The number of cycles in the run

c. The amount of fluorescent quencher

d. The initial amount of target DNA

d. The initial amount of target DNA

27. Which of the following practices should be employed

to prevent contamination of patient samples and

reagents with amplicons?

a. Use bleach solution for cleaning work area

b. Use UV lights in hooded work area

c. Maintain closed analytical systems

d. All of the above

d. All of the above

28. Which of the following statements is true regarding

agarose gel electrophoresis?

a. Nucleic acids are separated in an electrical field

because of their net positive charge

b. Larger nucleic acid molecules are able to migrate

through the agarose gel faster than smaller

molecules

c. Nucleic acids are separated in agarose by shape,

charge, and size

d. Agarose is a dye that binds in doublestranded

DNA

c. Nucleic acids are separated in agarose by shape,

charge, and size

29. PCR requires all of the following components except:

a. Deoxynucleotide triphosphates

b. DNA endonuclease

c. DNA polymerase

d. Oligonucleotides (primers)

b. DNA endonuclease

30. What is the purpose of the primer extension?

a. To cut the native DNA into small pieces with a

restriction enzyme

b. To hybridize the oligonucleotide primers to the

single-stranded DNA pieces

c. To produce PCR amplicons

d. To activate the DNA polymerase to form hybrids

with the oligonucleotide primers

c. To produce PCR amplicons

31. The most common nucleic acid stain used after separation

by agarose gel electrophoresis is:

a. Bromothymol blue

b. Bromocresol green

c. Ethidium bromide

d. Phenolphthalein

c. Ethidium bromide

32. This method is based on the microscopic grouping

of probe DNA molecules attached to a solid support

mechanism such as glass, silicon, or plastic

chips.

a. DNA microarray

b. Multilocus enzymes electrophoresis

c. Restriction fragment length polymorphism (RFLP)

d. Polymerase chain reaction (PCR)

a. DNA microarray

33. The field of proteomics studies which of the

following?

a. Proteins on a cellular level

b. Serum proteins

c. Proteins in genes

d. The human genome

a. Proteins on a cellular level

34. Which of the following is not a factor that influences

hybridization reactions?

a. Degree of complementarity between the probe

and target nucleic acid

b. pH

c. Size of the target's genome

d. Temperature

c. Size of the target's genome

35. Which of the following is false about primers?

a. Primers should be at least 100 nucleotides long

b. Primers are typically 15 to 30 nucleotides long

c. Primers should have a GC percentage of 40%

to 60%

d. Primers should anneal to a specific target

a. Primers should be at least 100 nucleotides long

36. In a chain-termination DNA sequencing reaction,

which one of the following components are tagged

with a fluorescent dye?

a. Dideoxynuclotide triphosphates (ddNTP)

b. Deoxynucleotide triphosphates (dNTP)

c. Pyrophosphates (PPi)

d. Capillary probe (CaP)

a. Dideoxynuclotide triphosphates (ddNTP)

37. Pyrosequencing sequence analysis and quantification

depends on the release of ________ in a quantity

equal to that of an incorporated dNTP.

a. Apyrase

b. Luciferase

c. Nucleotides

d. Pyrophosphate

d. Pyrophosphate

38. In which of the following inheritance patterns are

homozygous alleles necessary to express the disease

phenotype?

a. Autosomal dominant

b. X-linked dominant

c. Autosomal recessive

d. Trinucleotide repeats

c. Autosomal recessive

39. The differential activation of genes depending on

the parent from which they are inherited is referred

to as:

a. Allelic heterogeneity

b. Imprinting

c. Mosaicism

d. Pleiotropy

b. Imprinting

40. What is the preferred specimen type for molecular

studies for the diagnosis of inherited mutations?

a. RNA extracted from peripheral mature red cells

b. RNA extracted from fresh serum

c. DNA extracted from peripheral blood white cells

d. DNA extracted from peripheral blood mature

red cells

c. DNA extracted from peripheral blood white cells

41. A type of polymorphism that consists of a series of

trinucleotide repeats that can be two to seven base

pairs in length and is known as a microsatellite

sequence is also referred to as a:

a. Restriction fragment length polymorphism

(RFLP)

b. Variable number tandem repeat (VNTR)

c. Restriction endonuclease

d. Short tandem repeat (STR)

d. Short tandem repeat (STR)

42. The site of a particular nucleotide sequence on a

chromosome is referred to as a(n):

a. Allele

b. Locus

c. Polymorphism

d. Genotype

b. Locus

43. The HLA A, B, and C molecules are encoded for by

which class gene(s)s within the major histocompatibility

complex (MHC)?

a. Class I

b. Class II

c. Class III

d. All groups in MHC class

a. Class I

44. The detection of the DNA from cytomegalovirus

(CMV) and human papillomavirus (HPV) is typically

performed using the Hybrid Capture assay. What

type of assay is Hybrid Capture?

a. Target amplification assay

b. Signal amplification assay

c. Reverse transcriptase assay

d. Viral load assay

b. Signal amplification assay

45. The major advantage for using nucleic acid techniques

for the identification of infectious disease is:

a. The lower cost involved with molecular analysis

b. The high specificity for identification of an

organism

c. The lack of false negatives

d. The ability to distinguish normal flora from

disease-causing organisms

b. The high specificity for identification of an

organism

46. Which of the following genes is not found in

retroviruses?

a. Gag

b. Pol

c. Env

d. Onc

d. Onc

47. In chronic myeloid leukemia (CML) the fusion of

chromosomes 9 and 22 produces a hybrid gene,

BCR-ABL. This chromosome is referred to as the:

a. Cincinnati chromosome

b. Legionnaires chromosome

c. Myeloprolifererative chromosome

d. Philadelphia chromosome

d. Philadelphia chromosome

48. The technique that uses fluorescent DNA probes to

detect chromosomal abnormalities within cells in

cytogenetic studies is referred to as:

a. Fluorescence in situ hybridization (FISH)

b. Karyotype in situ hybridization (KISH)

c. Fluorescence in situ PCR

d. Microarray

a. Fluorescence in situ hybridization (FISH)

49. A tumor-suppressor gene performs which of the following

task(s)?

a. Codes for normal growth-promoting proteins

b. Codes for proteins that control cell division

c. Repairs nucleotide mismatches in theDNAstrand

d. All of the above

d. All of the above

50. Which term describes a normally occurring gene that

when altered is often associated with cancers?

a. Oncogene

b. Proto-oncogene

c. Meta-oncogene

d. Post-oncogene

b. Proto-oncogene