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Molecular Pathology

DNA Sequencing Practice Questions

20 free DNA Sequencing practice questions for the Pathology, each with the correct answer and a detailed explanation. Open any question below, or take the full set as an interactive quiz.

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All DNA Sequencing questions

20 questions
  1. Q1. What is the primary purpose of using fluorescently labeled dideoxynucleotides (ddNTPs) in Sanger sequencing?
  2. Q2. In next-generation sequencing (NGS), what is the primary function of bridge amplification?
  3. Q3. A molecular pathologist identifies a homozygous deletion in the SMN1 gene using MLPA. What is the primary limitation of this technique compared to NGS?
  4. Q4. During Illumina sequencing-by-synthesis, what causes the specific fluorescence emission during each cycle?
  5. Q5. What is the role of proteinase K in the DNA extraction process prior to sequencing?
  6. Q6. In the context of clinical NGS, what does 'depth of coverage' refer to?
  7. Q7. A tumor sample shows an allele frequency of 5% for a specific KRAS mutation. Which sequencing artifact is most critical to rule out before reporting this findi…
  8. Q8. What distinguishes third-generation sequencing (e.g., Oxford Nanopore) from second-generation sequencing (e.g., Illumina)?
  9. Q9. During variant calling in germline testing, why is it essential to sequence the proband's parents (trio analysis)?
  10. Q10. In Sanger sequencing chromatograms, what does a broad, double-peak pattern beneath a single nucleotide position typically indicate?
  11. Q11. What is the primary advantage of using targeted gene panels over whole-exome sequencing (WES) in a clinical oncology setting?
  12. Q12. The term 'read' in DNA sequencing refers to:
  13. Q13. Why is bisulfite sequencing specifically utilized in epigenetic studies?
  14. Q14. What is the primary bioinformatic challenge presented by homopolymer regions in Ion Torrent sequencing data?
  15. Q15. Which quality control metric is most indicative of successful library preparation for NGS?
  16. Q16. A researcher is studying a pathogen with a high AT-rich genome. Which sequencing technology is generally considered most challenging for this type of genome?
  17. Q17. In the context of precision oncology, what is the significance of 'tumor mutational burden' (TMB) derived from NGS data?
  18. Q18. What is the purpose of incorporating unique molecular identifiers (UMIs) into NGS libraries?
  19. Q19. Which factor most significantly contributes to 'allelic dropout' in PCR-based sequencing assays?
  20. Q20. A pathologist receives a VCF file from a sequencing run. What specific information is found in the 'GT' field of the FORMAT column?