mi WebXam Dress Rehearsal

A full, timed run-through of the blueprint. Enter your Student ID and answer each item. This is a check against the WebXam blueprint, not a grade. You will see some of these questions again at the next checkpoint.

1. 1. The main purpose of PCR is to:

   ACut DNA at a specific recognition siteBSeparate DNA fragments by sizeCRead the order of bases in a DNA strandDMake many copies of one DNA region

2. 2. On a DNA gel, the fragments that travel farthest are the:

   ABrightest, thickest bandsBMost negatively charged fragmentsCSmallest fragmentsDLargest fragments

3. 3. A BLAST hit with an E-value of 1e-50 versus one of 5.0 is:

   AA much stronger matchBAn equally good matchCA much weaker matchDA match of unknown strength

4. 4. An ELISA that calls a healthy person positive has produced a:

   AFalse negativeBFalse positiveCTrue positiveDTrue negative

5. 5. A restriction enzyme is used to:

   ACut DNA at a specific sequenceBJoin two DNA fragments end to endCMake many copies of a DNA regionDMake DNA bands visible in a gel

6. 6. A bright spot on a gene-expression microarray means that gene is:

   AMutated in the sampleBTurned off in the sampleCDuplicated in the sample's genomeDHighly expressed in the sample

7. 7. In gene therapy, a viral vector is used to:

   ADeliver a working gene into cellsBCut the faulty gene out of the DNACRead the patient's DNA sequenceDGive the patient an active viral infection

8. 8. A key safety concern with CRISPR editing is:

   AFailure to work in human cellsBEditing of RNA instead of the DNA geneCOff-target cuts at similar sequencesDLoss of the edit as the cell divides

9. 9. A SNP is a:

   ADifference at a single DNA baseBPiece of DNA that codes for one proteinCShort repeat of bases used in DNA fingerprintingDMissing copy of a chromosome

10. 10. To make human insulin in bacteria, you first:

    AInsert the insulin gene into a plasmidBInject the insulin gene into the patientCSequence the patient's whole genomeDPurify insulin from the patient's blood

11. 11. A tumor suppressor gene normally:

    ACopies DNA before the cell dividesBBlocks apoptosis in damaged cellsCPuts the brakes on the cell cycleDSpeeds up uncontrolled division

12. 12. Leaving a culture plate uncovered on the bench most likely causes:

    ASterilization by the room's lightBNo change, since the agar is sterileCContamination by airborne microbesDFaster growth from the extra oxygen

13. 13. One bacterial colony on a plate grew from:

    ANutrients in the agar clumping togetherBA virus growing on the plateCOne colony-forming unit: one cell or an attached clumpDA mix of different bacterial species

14. 14. A larger clear zone around an antibiotic disk means the bacteria are:

    AMore resistant to itBUnable to grow anywhere on the plateCContaminated with another speciesDMore susceptible to it

15. 15. Resistance genes spread quickly between bacteria mainly via:

    APlasmids by horizontal transferBThe patient's immune system weakeningCNew mutations arising in each cellDAntibiotics changing the bacteria's DNA

16. 16. Before handling a new reagent, you should first check its:

    ASafety Data Sheet (SDS)BMolecular weight on the labelCExpiration date on the bottleDHazard color code on the label

17. 17. Three sequential 1:10 dilutions give a final dilution of:

    A1:10000B1:30C1:100D1:1000

18. 18. "The disease will likely progress over years" is a:

    APrognosisBLab valueCChief complaintDDiagnosis

19. 19. An outbreak line list has one row per:

    ADay, with the new case countBCase, with onset and exposuresCSymptom, with how many reported itDLab test, with its result

20. 20. Herd immunity protects unvaccinated people because:

    AToo few susceptible hosts remainBThe vaccine spreads from person to personCNearby immune people share antibodiesDThe vaccine cures people already sick

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