This set of Vector Biology Multiple Choice Questions & Answers (MCQs) focuses on “Vectors for Yeast – 3”.
1. What is the approximate copy number of Yeast Episomal plasmids?
Explanation: Several factors come into play while deciding the type of vector to be used in a cloning experiment. Copy number is one of them.
2. Which of the following has the lowest copy number per cell?
Explanation: Yeast Integrative plasmids have the lowest copy number of all the yeast plasmid derived vectors. It is present only one copy per cell.
3. Why are copy numbers important in a cloning experiment?
a) Maximum expression
b) Ease of manipulation
c) Cost efficiency
d) Availability of stock
Explanation: The copy numbers are essential if the objective is to obtain protein from the cloned gene, as the more copies there are of the gene the greater the expected yield of the protein product.
4. Despite their low copy number, why are YIPs still used?
a) Stable recombinants
b) Easy availability
c) Star activity
d) Wider host range
Explanation: Yeast integrative plasmids produce extremely stable recombinants, like loss of a YIP that has become integrated into a chromosome occurs at only a very low frequency.
5. YRP recombinants are extremely unstable.
Explanation: Yeast replicative plasmids are extremely unstable, the plasmids tending to congregate in the mother cell when a daughter cell buds off.
6. What are YAC vectors?
a) Yeast artificial vectors
b) Yeast aggregative vectors
c) Yeast artificial chromosomes
d) Yeast aggregative chromosomes
Explanation: Yeast artificial chromosomes present a totally different approach to gene cloning. Individual components are isolated by recombinant DNA techniques.
7. What are telomeres?
c) Chromosomal ends
d) Gene component
Explanation: Telomeres are chromosomal ends that prevent the shortening of a chromosome and are also necessary for correct replication.
8. What are the origins of replication?
a) Gene component
b) Initiation sites
c) Initiation codons
d) Stop codons
Explanation: Origins of replication are the sites on a chromosome where the replication is initiated. These sites are present on both a chromosome and a plasmid.
9. What is an artificial chromosome?
a) Isolated from in vivo
b) Created in the test tube
c) Chromosome of a yeast
d) A bacterial chromosome
Explanation: An artificial chromosome is the one created in a test tube. All the components of the original chromosome are first isolated using recombinant techniques and then mixed in test tube to create an artificial chromosome.
10. What is pYAC3?
a) Yeast artificial chromosome
b) Plasmid vector
c) Hybrid of phage and plasmid
d) Yeast chromosome
Explanation: pYAC3 is essentially a Pbr322 plasmid into which a number of yeast genes have been inserted. It is a typical example of a yeast artificial chromosome vector.
11. Which of the following is not present in a YAC3 vector?
Explanation: TRP1 and URA3 are the only two selectable markers that a Pyac3 vector harbors. There are no genes for ampicillin resistance.
12. What is the CEN4 region in the YAC vector?
a) DNA from centromere
b) DNA from telomere
c) DNA from origin
d) Bacterial DNA
Explanation: The DNA fragment that carries TRP1 in a YAC vector also carries a sequence called CEN4, which is the DNA from the centromere region of chromosome 4.
13. What do the sequences TEL signify in a YAC vector?
c) Gene center
Explanation: TEL regions provide the telomeres. These are not themselves complete telomere sequences but once inside the yeast nucleus they act as seeding sequences on which telomeres build.
14. In which region in the YAC vector is the new DNA inserted in a cloning experiment?
Explanation: SUP4 is the selectable marker into which new DNA is inserted during a cloning experiment. It is located between the regions CEN4 and URA3.
Sanfoundry Global Education & Learning Series – Vector Biology & Gene Manipulation.
To practice all areas of Vector Biology & Gene Manipulation, here is complete set of 1000+ Multiple Choice Questions and Answers.