Previous Solved GATE Biotechnology Questions

1. Highest capacity vector is
a) Cosmid
b) YAC
c) Yeast integrative vector
d) Bacteriophage vector
Ans: b
  • 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 a
            a) Diploid
            b) Haploid
            c) Aneuploid
            d) Polyploid

  • 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 breakpoint
b) Apoptopsis
c) Various stages of Cell cycle
d) 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 structure
b) Its 2’ OH groove participate in intramolecular cleavage of phosphodiester backbone
c) Cleavage occurs in the glycosilic bonds of purine bases
d)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 template
b) NTPs
c) MgCl2
d) 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) SNPs
b) RFLPs
c) FISH analysis
d) Either RFLP analysis or SNP
Ans: d
  • 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 Cytokinin
b) Auxin and Gibberellin
c) Cytokinin and Gibberellin
d) Ethylene and Gibberllin
Ans: a
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 species
b) Complete the growth of embryos susceptible to defects in seed development
c) Break the dormancy of seeds
d) All of the above

9. Antibody diversity is generated by
a) protein splicing
b) somatic mutations
c) allelic exclusion
d) interchromosomal recombination
Ans: b
  • 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 acid
b)Acetic acid
c)Phenoxy acetic acid
d)None of the above

11. Plastome is
a)Plasmalemma protein
b)A type of plasmid
c)An organellar genome
d)None of the above
Ans: plastome: Genetic material of plastid like Chloroplast
12. Which of the following process require energy
a) ligation
b) restriction digestion
c) hybridization
d) transformation
Ligation: sealing of single stranded nicks or breaks by ligase enzyme. The process requires ATP and NADP+.
13) Enhanced axillary branching for multiple shoot production is promoted by
b) Abscisic acid
c) BA (Benzyl adenine)
d) Gibberellic acid
2,4-D is an auxin and auxin is responsible for sustaining apical dominance there by promoting axillary branching
14. Viral replication within cells is inhibited by
a) IL-4
b) IL-1
c) IFN alpha
d) TNF alpha
Interferons: are antiviral agents (proteins) secreted by virus infected cells and induces a virus resistant state to the surrounding cells by inhibiting its replication.
15. In the course of cell cycle, the level of the protein cyclin abruptly falls during
a) G1phase
b) G2 phase
c) S phase
d) M phase


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