Gene Manipulation Multiple Choice Questions on “Genomic and cDNA Libraries”.
1. The first genomic libraries were cloned in _______________
A. Plasmid
B. Bacteria
A. Human
D. Plants
Answer: A
Clarification: Genomic DNA libraries are generated by fragmenting the genome and cloning overlapping fragments in vectors. The first libraries were cloned in simple plasmids and phage vectors.
2. Genomic library construction is concerned with ___________
A. Gene isolation
B. Protein production
A. Antibiotics
D. Regeneration
Answer: A
Clarification: Genomic libraries are useful to examine how we can study and isolate a given gene; the basic principles apply to all genomes.
3. Which DNA is restricted to making a genomic library?
A. Genomic
B. Plasmid
A. Phage
D. Plant
Answer: A
Clarification: Total genomic DNA of an organism is digested using restriction endonuclease and the fragments are inserted into a suitable phage.
4. What is the approximate size of fragments given off by EcoR1?
A. 1 kb
B. 2 kb
A. 3 kb
D. 4 kb
Answer: D
Clarification: EcoR1 is a restriction endonuclease; that is it cleaves the DNA within the double helical structure and gives off the fragments of approximately 4 kb in size.
5. A genomic library is a collection of _____________
A. Genes
B. Proteins
A. Vectors
D. Recombinants
Answer: D
Clarification: A very large number of recombinants are produced by restricting with endonucleases and then inserting them into suitable vectors, to make up a genomic library.
6. If a gene is large, it may be cut more than once by an endonuclease.
A. True
B. False
Answer: A
Clarification: If a gene is large then it can harbor many recognition sites for an endonuclease and therefore it may be cleaved more than once.
7. The Clarke and Carbon formula relates the ____________ of including a DNA fragment in a random library.
A. Probability
B. Effects
A. Temperature change
D. Vector requirement
Answer: A
Clarification: The Clarke and Carbon formula, developed in 1976 relates the probability of including any DNA sequence in a random library of N independent recombinants.
8. In the strategy devised by Maniatis, how many restriction enzymes were used?
A. 1
B. 2
A. 3
D. 4
Answer: B
Clarification: In order to control the size of digested fragments that eventually are inserted in vectors, two restriction enzymes were used by Maniatis.
9. The restriction enzymes used by Maniatis had recognition site of ____ nucleotides.
A. 1
B. 2
A. 3
D. 4
Answer: D
Clarification: The restriction endonucleases used in the strategy developed by Maniatis in 1978; had tetranucleotide restriction site.
10. Which kind of packing is done for the fragmented genes?
A. In vivo
B. Population
A. Group
D. In vitro
Answer: D
Clarification: In vitro packaging ensures that appropriately large number of independent recombinants can be recovered. Packaging is done by inserting the genes into the vectors.
11. HaeIII and AluI have ___________ recognition sites.
A. Different
B. Similar
A. Short
D. Unrecognizable
Answer: A
Clarification: HaeIII and AluI are restriction endonucleases and have completely different recognition sites which generate random DNA fragments.
12. Linkers are required when using enzymes HaeIII and AluI.
A. True
B. False
Answer: A
Clarification: Both these enzymes have completely different recognition sites and hence produce randomly fragmented genes. Blunt ends are produced and linkers are required.
13. The ‘Charon series’ belongs to series of ____________
A. Genes
B. Vectors
A. Hosts
D. Enzymes
Answer: B
Clarification: The Charon series was developed by Blattner and Williams in 1979 and included insertional vectors and replacement vectors.
14. Sau3AI is a _______ restriction endonuclease.
A. Single
B. Double
A. Hybrid
D. Weak
Answer: A
Clarification: Sau3AI is a single restriction endonuclease that cuts frequently and allows for a convenient simplification for the generation of genes.
15. Lambda EMBL3 is a ____________
A. Gene
B. Phage
A. Phage Vector
D. Protein
Answer: C
Clarification: Lambda EMBL3 is a replacement vector. Fragments digested with Sau3AI which is a single restriction enzyme can be readily inserted into this vector.