1. Why is a eukaryotic cloning vector required?
a) Cloning ease
b) Variety
c) Availability
d) Large scale production
Explanation: At times mere study of the gene is not the goal of a cloning experiment. Especially in biotechnology when the aim to obtain large amounts of product vectors and cell systems other than the prokaryotic ones are used.
2. Plasmids are present in eukaryotes.
a) true
b) false
Explanation: Plasmids are usually the extrachromosomal entities of a plasmid however a plasmid is also present in some strains of yeast
3. Saccharomyces cerevisiae is an example of _________
a) Fungi
b) Yeast
c) Bacteria
d) Insect
Explanation: After the extensively used E.coli in the recombinant DNA technology, next comes S.cerevisiae which is a yeast and a eukaryotic organism.
4. After the extensively used E.coli in the recombinant DNA technology, next comes S.cerevisiae which is a yeast and a eukaryotic organism.
a) Phage
b) Plasmid
c) Virus
d) Gene product
Explanation: The 2 micrometer circle found in yeast is the only plasmid of eukaryotic origin. The discovery of this plasmid has stimulated the use of yeast as a cloning vector.
5. What is the size of 2 micrometer circle?
a) 1 kb
b) 6 kb
c) 11 kb
d) 22 kb
Explanation: The 2 micrometer circle is approximately 6 kb in size, well within the range of an ideal vector. It is present in a yeast cell at a copy number of between 70 and 200.
6. What are REP1 and REP2 genes in the plasmid used for?
a) Origin
b) Replication
c) Expression
d) Host lysis
Explanation: Replication makes use of origin of replication, sever enzymes provided by the host and the REP1 and REP2 genes encoded by the plasmid.
7. Which selection system is used in a yeast plasmid recombinant?
a) Antibiotic
b) Lac
c) Auxotrophic mutant
d) cI gene
Explanation: A normal yeast gene which codes for an enzyme involved in amino acid biosynthesis is incorporated into the vector. The host that is selected has a mutated copy of the incorporated plasmid gene.
8. What is an auxotrophic mutant?
a) Defective plasmid
b) Transformed cell
c) Host cell
d) Yeast cell
Explanation: An auxotrophic mutant is a host cell that lacks or has a mutated copy of a gene coding for an enzyme involved in an essential amino acid biosynthesis
9. What does the gene LEU2 code for?
a) Lactose
b) Leucine
c) Dehydrogenase
d) Hydrogenase
Explanation: LEU2 is a gene coding for the enzyme beta-isopropyl-malate-dehydrogenase, one of the enzymes involved in the conversion of pyruvic acid to leucine.
10. On which medium are yeast plasmids transformed cells plated?
a) Luria Broth
b) Agar
c) Minimal
d) Nutrient
Explanation: Minimal medium contains no added amino acids and therefore cells that produce all the amino acids can only grow. Transformed cells are only able to grow on minimal medium.