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11.1 Restriction Enzymes & Cloning Vectors β Test 1
Q1. A widely used engineered plasmid cloning vector with a polylinker and blue-white screening is:β pUC19
Q2. Plasmids used in genetic engineering are:β Circular double-stranded DNA
Q3. A restriction endonuclease is often described as the:β Molecular scissors
Q4. Restriction enzymes that recognise the same nucleotide sequence are called:β Isoschizomers
Q5. Restriction enzymes that recognise the same site but cleave at different positions within it are called:β Neoschizomers
Q6. Which recognition/cut pattern represents a type-II enzyme that generates sticky (cohesive) ends?β 5'-GβGATCC-3' (BamHI-type)
Q7. In site-directed mutagenesis, which enzyme is used to digest the methylated parental DNA template?β DpnI
Q8. Which vector is used to clone very large DNA fragments (>300 kb)?β Bacterial artificial chromosome (BAC)
Q9. Which vector is most suitable to clone a 220-kb fragment?β BAC
Q10. Yeast artificial chromosomes (YACs) are used for cloning:β Very large segments of DNA
Q11. Blue-white screening with pUC vectors is based on:β Ξ±-complementation of Ξ²-galactosidase
Q12. Which antibiotic-resistance marker is generally NOT useful in a cloning vector for Gram-negative bacteria?β Vancomycin
Q13. T4 DNA ligase, compared with E. coli DNA ligase, and with PEG/Ficoll added:β Ligates blunt ends better, and crowding agents raise its efficiency (both true)
Q14. A restriction enzyme cut that leaves single-stranded overhangs produces:β Cohesive (sticky) ends
Q15. The multiple cloning site (polylinker) of a vector is a:β Region of many unique restriction sites for inserting DNA
Q16. The origin of replication (ori) in a cloning vector determines:β The vector's copy number and host range
Q17. A selectable marker in a cloning vector is usually a(n):β Antibiotic-resistance gene
Q18. An expression vector differs from a simple cloning vector in that it additionally contains:β A promoter (and translation signals) to drive expression of the cloned gene
Q19. A shuttle vector is one that can:β Replicate in two different host species (e.g. E. coli and yeast)
Q20. Match each tool/term with its description and select the correct option.β A-ii, B-iv, C-i, D-iii