Genomic & Biotechnology Technician Prometric exam questions with answers

1. Question 1Basic Laboratory Skillsmedium

   A protocol calls for pipetting 50 microlitres of a viscous 50% glycerol solution accurately. Which technique helps most?

   1. AForward pipetting with fast plunger release to avoid bubbles
   2. BPipetting with a tip rinsed in ethanol before each draw
   3. CUsing a pipette set far above the target volume
   4. DReverse pipetting with a slow, steady plunger action
   Show answer and explanation▾

   Answer: D. Reverse pipetting with a slow, steady plunger action

   Reverse pipetting reduces error with viscous liquids because the liquid is not blown out fully, and slow handling lets it fill the tip. Fast release causes inaccurate volumes, ethanol contaminates the sample, and an unsuitable range reduces accuracy.

   Reference: Green and Sambrook, Molecular Cloning: A Laboratory Manual, 4th ed., 2012

2. Question 2Bioinformaticshard

   A genome-wide association study tests about one million independent variants. Why is the usual significance threshold set near 5 x 10^-8?

   1. ABecause p-values smaller than 0.05 are not computed by software
   2. BTo make the study need far fewer samples than a smaller study would
   3. CBecause association studies are limited to testing rare variants
   4. DTo correct for multiple testing, so false positives stay rare
   Show answer and explanation▾

   Answer: D. To correct for multiple testing, so false positives stay rare

   Testing many variants inflates false positives, so the threshold is tightened, roughly 0.05 divided by the number of independent tests. It does not reduce sample needs, and p-values below 0.05 are computable.

   Reference: Pe'er et al., Genetic Epidemiology 2008;32:381-385

3. Question 3Bioinformaticsmedium

   Variants from a lab are on GRCh37 coordinates, but the annotation database uses GRCh38. What should be done before annotation?

   1. AAnnotate directly because coordinates are the same
   2. BDelete the position column
   3. CChange the chromosome names to lower case
   4. DConvert the coordinates with a tool such as liftOver or re-align to GRCh38
   Show answer and explanation▾

   Answer: D. Convert the coordinates with a tool such as liftOver or re-align to GRCh38

   Positions differ between builds, so variants must be converted or re-aligned. Using them directly gives wrong annotations, and removing columns or editing names does not fix it.

   Reference: Pevsner, Bioinformatics and Functional Genomics, 3rd ed., 2015

4. Question 4Biotechnologymedium

   On a blue-white screening plate with X-gal and IPTG, a white colony usually indicates what?

   1. AThe cell lacks the plasmid and is antibiotic-sensitive
   2. BThe insert disrupted the lacZ alpha gene, so no blue product formed
   3. CThe cell is producing more beta-galactosidase than blue colonies
   4. DThe plasmid is empty and intact
   Show answer and explanation▾

   Answer: B. The insert disrupted the lacZ alpha gene, so no blue product formed

   A DNA insert in the lacZ alpha region stops beta-galactosidase from cleaving X-gal, so colonies stay white. Cells without plasmid do not grow on selection, and an intact empty plasmid gives blue colonies.

   Reference: Green and Sambrook, Molecular Cloning: A Laboratory Manual, 4th ed., 2012

5. Question 5Biotechnologyeasy

   Adherent cells have reached confluence. Which step belongs in routine subculture?

   1. AScrape the cells with a metal blade and freeze the whole flask at once
   2. BDetach with trypsin-EDTA, neutralise with serum medium and reseed
   3. CAdd more fresh medium on top of the cells without detaching them first
   4. DHeat the flask to 56 degrees Celsius for 30 minutes before reseeding
   Show answer and explanation▾

   Answer: B. Detach with trypsin-EDTA, neutralise with serum medium and reseed

   Trypsin-EDTA lifts adherent cells, serum neutralises it and reseeding at lower density restores growth. Scraping, doing nothing and heating are not standard subculture.

   Reference: Freshney, Culture of Animal Cells, 7th ed., 2016

6. Question 6Biotechnologymedium

   A recombinant protein with a six-histidine tag is purified from lysate. Which method is typical?

   1. ASize selection by agarose gel electrophoresis followed by gel extraction
   2. BIon exchange chromatography run at the isoelectric point of the protein
   3. CPrecipitation with ethanol followed by a spin
   4. DImmobilised metal affinity chromatography, with elution by imidazole
   Show answer and explanation▾

   Answer: D. Immobilised metal affinity chromatography, with elution by imidazole

   A His tag binds nickel or cobalt resin, and imidazole competes to release the protein. Agarose gels separate nucleic acids, ion exchange is a different principle, and ethanol precipitation is not specific.

   Reference: Protein Purification Techniques: A Practical Approach, 2nd ed.

7. Question 7Biotechnologymedium

   A cell culture shows no turbidity or visible microbes, but cells grow slowly and look unhealthy. Which contaminant should the technician suspect?

   1. AMycoplasma, which is detected by PCR or DNA staining
   2. BBacteria, since the medium would look cloudy
   3. CYeast, since the medium would turn acidic and cloudy
   4. DPhage, since mammalian cells are infected by phage
   Show answer and explanation▾

   Answer: A. Mycoplasma, which is detected by PCR or DNA staining

   Mycoplasma is small, lacks a cell wall and does not cloud medium, so routine testing is needed. Bacteria and yeast usually cause visible changes, and phages infect bacteria, not mammalian cells.

   Reference: Freshney, Culture of Animal Cells, 7th ed., 2016

8. Question 8Biotechnologymedium

   A laboratory wants to confirm that a human cell line is the one named on its label. Which method is recommended?

   1. AShort tandem repeat profiling compared with a reference profile
   2. BCounting the number of cells per millilitre at each of several passages
   3. CMeasuring the colour of the culture medium after twenty-four hours
   4. DChecking the growth rate over a single passage in the same medium
   Show answer and explanation▾

   Answer: A. Short tandem repeat profiling compared with a reference profile

   STR profiling gives a unique DNA fingerprint that can be matched to reference lines. Cell counts, medium colour and growth rate do not identify a line.

   Reference: ANSI/ATCC ASN-0002-2022, Authentication of human cell lines by STR profiling

9. Question 9Biotechnologymedium

   Streptococcus pyogenes Cas9 is used for editing with a guide RNA. What does the enzyme require next to the target site?

   1. AA protospacer adjacent motif, NGG
   2. BA TATA box upstream of the target
   3. CA poly-A signal downstream of the target
   4. DA restriction site at the cut position
   Show answer and explanation▾

   Answer: A. A protospacer adjacent motif, NGG

   SpCas9 cuts only where an NGG PAM follows the target sequence. TATA boxes, poly-A signals and restriction sites are unrelated.

   Reference: Jinek et al., Science 2012;337:816-821

10. Question 10Genomicsmedium

    A patient's coding DNA has a two-base deletion. What is the most likely effect on the protein?

    1. AA silent change that leaves the protein sequence unaltered
    2. BA single amino acid swap at the position where the deletion occurred in the gene
    3. CAn in-frame loss of two amino acids with the rest of the protein unchanged
    4. DA frameshift altering downstream amino acids, often with a premature stop
    Show answer and explanation▾

    Answer: D. A frameshift altering downstream amino acids, often with a premature stop

    Deleting a number of bases not divisible by three shifts the reading frame. A silent change or a single missense swap involves substitution, and an in-frame loss needs a multiple of three.

    Reference: Clark, Pazdernik and McGehee, Molecular Biology, 3rd ed., 2019

11. Question 11Genomicsmedium

    A laboratory plans whole genome sequencing of a human germline sample. Which average coverage is typical?

    1. AAbout 0.1x
    2. BAbout 1000x
    3. CAbout 30x
    4. DAbout 5x
    Show answer and explanation▾

    Answer: C. About 30x

    Human germline whole genomes are usually sequenced at about 30x depth to call heterozygous variants confidently. 0.1x and 5x are low-pass and 1000x is for targeted panels.

    Reference: Goodwin et al., Nature Reviews Genetics 2016;17:333-351

12. Question 12Molecular Techniqueseasy

    DNA fragments are run on an agarose gel. Toward which electrode do they migrate, and why?

    1. AToward the negative electrode, because the bases are positively charged
    2. BToward the positive electrode, because the phosphate backbone is negatively charged
    3. CToward the positive electrode, because DNA is hydrophobic
    4. DThey do not move without a protein stain present
    Show answer and explanation▾

    Answer: B. Toward the positive electrode, because the phosphate backbone is negatively charged

    DNA carries a negative charge from its phosphate groups, so it moves toward the anode. The bases are not responsible for charge, hydrophobicity does not drive migration, and no protein stain is needed.

    Reference: Green and Sambrook, Molecular Cloning: A Laboratory Manual, 4th ed., 2012

13. Question 13Genomicsmedium

    A laboratory report lists a variant as a variant of uncertain significance. How should it be treated?

    1. AIt should not be used alone for clinical decisions and should be reviewed later
    2. BIt should be reported as pathogenic to be safe, so that the patient is followed closely
    3. CIt should be removed from the report because it is not informative
    4. DIt should be treated as benign unless the clinician asks the laboratory otherwise
    Show answer and explanation▾

    Answer: A. It should not be used alone for clinical decisions and should be reviewed later

    Under ACMG/AMP criteria, evidence is insufficient to call the variant pathogenic or benign, so it is reported as uncertain and reviewed later. Upgrading, deleting or downgrading it without evidence is wrong.

    Reference: Richards et al., ACMG/AMP variant interpretation, Genetics in Medicine 2015;17:405-424

14. Question 14Professional Practice/ Ethicseasy

    A blood sample arrives for genetic testing with a tube label that does not match the requisition form. What is the correct action?

    1. ADo not process it, document the discrepancy and request a new sample
    2. BCorrect the label from memory and process it so that the result is not delayed
    3. CProcess it now and fix the requisition form after the result is released
    4. DChoose whichever of the two names seems the most likely and then proceed
    Show answer and explanation▾

    Answer: A. Do not process it, document the discrepancy and request a new sample

    Mismatched identifiers risk sample swaps, so the sample must be rejected and recollected. Guessing or correcting it later compromises results.

    Reference: CLSI GP41, Collection of Diagnostic Venous Blood Specimens, 7th ed., 2017

15. Question 15Molecular Techniquesmedium

    The no-template control in a PCR run shows a clear amplification band. What should the technician do?

    1. AReport the run, since the sample lanes themselves look normal on the gel
    2. BDiscard the run, replace the reagents and decontaminate the workspace
    3. CRaise the annealing temperature and read the same gel again on the next day
    4. DAdd more primers to the reaction so that they outcompete the contaminating template
    Show answer and explanation▾

    Answer: B. Discard the run, replace the reagents and decontaminate the workspace

    Amplification in a no-template control means contamination by template or amplicon, so the run is invalid and sources must be removed. Ignoring it, changing temperature or adding primers does not remove contamination.

    Reference: Bustin et al., The MIQE guidelines, Clinical Chemistry 2009;55:611-622

Last reviewed September 2026. Questions are original and written to the published exam blueprint; they are not taken from any real paper.