Biotechnology and its Applications Test - 1

Hybrid or chimeric DNA is an aggregation of DNAs of two different organisms. This is also known as recombinant DNA or rDNA.

Ori - for origin of replication, is a restriction site for insertion of desired gene.

Restriction endonucleases break dsDNA at the palindromic sequence in 5'-3' direction.

Type II restriction enzymes are heavily used in recombinant DNA techniques. Type II enzymes consist of single, separate proteins for restriction and modification. One enzyme recognises and cuts DNA, the other enzyme recognises and methylates the DNA.
Type II restriction enzymes cleave the DNA sequence at the same site at which they recognise it. The only exception is Type II (shifted) restriction enzymes, which cleave DNA on one side of the recognition sequence, within twenty nucleotides of the recognition site.

EcoRI creates 4 nucleotide sticky ends with 5' end overhangs of AATT. The nucleic acid recognition sequence, where the enzyme cuts are G/AATTC, has a palindromic, complementary sequence of CTTAA/G.

HaeIII produces blunt end products.

--amp--tet-- are ampicillin and tetracycline markers for identification and isolation of transformed cloning vectors.

Correct answer. After the action of endonuclease, the dsDNA of plasmid breaks.

rDNA technology is for cloning of desired gene DNA.

A cloning vector is a small piece of DNA, taken from a virus, a plasmid, or the cell of a higher organism, that can be stably maintained in an organism, and into which a foreign DNA fragment can be inserted for cloning purposes.