Quick revision: every question with its correct answer. For the full explanation, open the test and tap View Solution.
1.2 Molecular Cloning & Vectors — Test 2
Q1. The restriction enzyme EcoRI recognises and cleaves the sequence:✓ GAATTC
Q2. A restriction enzyme that cuts both DNA strands at the same position, producing blunt ends, is exemplified by:✓ SmaI
Q3. A shuttle vector is one that can:✓ Replicate in two different host species
Q4. The bacteriophage M13 is particularly useful in cloning because its mature form contains:✓ Single-stranded DNA
Q5. A phagemid is a vector that combines features of a plasmid with:✓ A phage (e.g. M13) origin of replication
Q6. The Klenow fragment of DNA polymerase I is used to fill in 5' overhangs because it retains polymerase activity but lacks:✓ 5'→3' exonuclease activity
Q7. Insertion of foreign DNA into the lacZ' gene of a vector causes loss of blue colour because it leads to:✓ Insertional inactivation of β-galactosidase
Q8. The short stretch of DNA in a vector containing many unique restriction sites is called the:✓ Multiple cloning site (polylinker)
Q9. Directional cloning, which forces the insert into the vector in a defined orientation, is achieved by:✓ Cutting insert and vector with two different enzymes
Q10. In a T7-based expression system, high-level transcription of the cloned gene requires:✓ T7 RNA polymerase
Q11. Short, chemically synthesised double-stranded DNA pieces added to blunt ends to create restriction sites are called:✓ Linkers
Q12. A high-copy-number plasmid is generally preferred for cloning when the goal is to:✓ Obtain a large yield of the cloned DNA
Q13. TA cloning takes advantage of the fact that Taq polymerase adds a single overhanging:✓ 3' adenine (A) to PCR products
Q14. To clone a 40 kb fragment and package it into phage particles in vitro, the most suitable vector is a:✓ Cosmid
Q15. The host organism most commonly used for routine DNA cloning is:✓ Escherichia coli
Q16. A genomic library is best defined as a collection of clones that together contain:✓ The entire genome of an organism
Q17. Selection of transformed cells on an ampicillin plate works because the plasmid-borne bla gene encodes:✓ β-lactamase, which inactivates ampicillin
Q18. An inducible promoter is preferred in expression vectors mainly because it allows:✓ Control over when the cloned gene is expressed
Q19. During in-vitro packaging of lambda or cosmid DNA, the DNA is recognised and cut for packaging at the:✓ cos sites
Q20. Match each enzyme with its role in cloning and select the correct option.✓ A-iii, B-i, C-iv, D-ii