11.Gel electrophoresis is used for          a)     Construction of recombinant DNA by joining with cloning vectors          b)     Isolation of DNA molecules          c)     Cutting of DNA into fragments      d) Separation of DNA fragments according to their size 12. Plasmids are extrachromosomal circular DNA molecules a)   Which have their own point of replication and can replicate independently b)   Which have their own point of replication and cannot replicate independently c)   Which do not have on point of replication and cannot replicate independent of bacterial chromosome DNA. d)   None of these 13. Recombinant DNA is achieved by cleaving the pro-DNAs by which of the following enzyme? a)   Legase b)   Primase c)   Exonucleases d)   Restriction endonuclease 14. Amplification of gene of interest by using DNA polymerase may go up to a)   0.1 million times b)   1.0 million times c)   1.0 billion time