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1.4 Expression Profiling & Molecular Markers — Test 1
Q1. The polymerase chain reaction (PCR) is used to:✓ Amplify a specific DNA sequence exponentially
Q2. The three main steps repeated in each PCR cycle are:✓ Denaturation, annealing and extension
Q3. The thermostable DNA polymerase widely used in PCR is:✓ Taq polymerase
Q4. The short oligonucleotides that define the region amplified in PCR are called:✓ Primers
Q5. To amplify and study an RNA transcript, the technique used is:✓ Reverse-transcription PCR (RT-PCR)
Q6. Real-time (quantitative) PCR, or qPCR, allows the amount of product to be measured during the reaction by detecting:✓ Fluorescence as product accumulates
Q7. A DNA microarray is used to measure:✓ The expression of thousands of genes simultaneously
Q8. RFLP (restriction fragment length polymorphism) detects variation based on differences in:✓ Restriction-site positions, producing fragments of different lengths
Q9. RAPD (random amplified polymorphic DNA) markers are generated using:✓ Short random primers without prior sequence knowledge
Q10. AFLP (amplified fragment length polymorphism) combines:✓ Restriction digestion with selective PCR amplification
Q11. Microsatellites (simple sequence repeats, SSRs) used as markers are:✓ Short tandem repeats that vary in copy number between individuals
Q12. VNTRs (variable number tandem repeats) and minisatellites are especially used in:✓ DNA fingerprinting (individual identification)
Q13. RFLP and microsatellite markers are described as 'codominant' because they:✓ Allow both alleles of a heterozygote to be distinguished
Q14. Gene expression at the RNA level (which genes are switched on) can be measured by:✓ Northern blotting, RT-qPCR or microarrays
Q15. The denaturation step of PCR is carried out at approximately:✓ 94-95 °C
Q16. The annealing temperature in a PCR is chosen mainly on the basis of the:✓ Melting temperature (Tm) of the primers
Q17. In a microarray experiment, the signal at each spot is produced by:✓ Hybridisation of labelled sample cDNA to the immobilised probe
Q18. A molecular marker is best defined as:✓ A DNA sequence with a known location that varies between individuals
Q19. RFLP polymorphisms were traditionally detected after restriction digestion by:✓ Southern blotting with a labelled probe
Q20. Match each molecular-marker technique with its basis and select the correct option.✓ A-ii, B-i, C-iv, D-iii