1. Highest capacity vector is
a) Cosmidb) YACc) Yeast integrative vectord) Bacteriophage vector
- Cosmid: A plasmid with a cos site of lambda phage.Insert size: 30-45 kb
- YAC: yeast artificial chromosome. Insert size: 1 Mb
- Bacteriophage vectors: refers to lambda and M13 phage vectors
- Lambda phage vectors: Insert size: 8-23 kb
- M13 vectors used for obtaining single stranded copies of cloned DNA that are suited for DNA sequencing
- BAC: Bacterial Artificial Chromosome. Insert size: 300 kb
2. The C value denotes the total number of DNA in aa) Diploid
- C value: Haploid DNA content of an organism or the amount of DNA in haploid nuclei like a gamete.
- C value paradox: refers to the phenomenon that huge genomic content has nothing to do with the complexity of an organism.For eg: Protists has genome size much larger than humans.
3. Cdc mutants are useful for the study of
a) Chromosome breakpointb) Apoptopsisc) Various stages of Cell cycled) Homeodomain
Ans: c cdc refers to cell division cycle
4. RNA is very much susceptible to hydrolysis in alkali because
a) It contains Uracil residues in its structureb) Its 2’ OH groove participate in intramolecular cleavage of phosphodiester backbonec) Cleavage occurs in the glycosilic bonds of purine basesd)Cleavage occurs in the glycosilic bonds of pyrimidine bases
- Because of the presence of 2’ OH group in the ribose sugar
- DNA is more stable than RNA because of the presence of H at 2’ position in DNA rather than OH in RNA.
5. Which one of the following is not a requirement of a PCR reaction?
a) DNA templateb) NTPsc) MgCl2d) Taq polymerase
Here the best option is MgCl2 even though it is required for DNA polymerase activity. (It can be avoided)
6. The heterozygosity of any locus can be ascertained by
a) SNPsb) RFLPsc) FISH analysisd) Either RFLP analysis or SNP
- SNP: single nucleotide polymorphism refers to the variation in the lengths of some DNA btw individuals due to single base changes
Application: used in DNA finger printing
- RFLP: restriction fragment length polymorphism: refers to the variation in the restriction fragment length between individuals of a species.
- FISH: florescence insitu hybridization: hybridizing fluorescently labelled DNA probes on to human chromosome preparations allows genes to be mapped directly to their chromosomal locations.
7. Hormone pairs requires for a callus to differentiate are
a) Auxin and Cytokininb) Auxin and Gibberellinc) Cytokinin and Gibberellind) Ethylene and Gibberllin
Auxin induces rooting whereas cytokinins promote shooting if supplied in optimum ratio.
8. Embryo rescue is a useful technique to
a) Grow /generate hybrids between different plant speciesb) Complete the growth of embryos susceptible to defects in seed developmentc) Break the dormancy of seedsd) All of the above
9. Antibody diversity is generated by
a) protein splicingb) somatic mutationsc) allelic exclusiond) interchromosomal recombination
- Somatic mutation: a mechanism by which point mutations are introduced into rearranged immunoglobulin variable region genes during activation and proliferation of B cells. It contributes significantly to antibody diversity.
- Allelic exclusion: a process that permits the expression of only one of the allelic forms of a gene. It contributes to specificity of IgGs
10. The precursor for penicillin-G biosynthesis during fermentation process is
a)Phenylacetic acidb)Acetic acidc)Phenoxy acetic acidd)None of the above