Plasmid DNA acts as a _________ to transfer a piece of alien DNA attached to it into the host organism.

[Biotechnology-Principles-and-Processes] [class-xii ]

• enzyme
• marker
• vector
• substrate
Correct Option: C  [ vector ]

Remark: Plasmid DNA acts as a vector to transfer the piece of DNA attached to it.

The linking of the antibiotic resistance gene with the plasmid vector was made possible by the enzyme _________.

[Biotechnology-Principles-and-Processes] [class-xii ]

• restriction endonuclease
• DNA ligase
• DNA polymerase
• ribonuclease
Correct Option: B  [ DNA ligase ]

Remark: DNA ligase acts on cut DNA molecules and joins their ends.

A new combination of circular autonomously replicating DNA created *in vitro* is known as _________.

[Biotechnology-Principles-and-Processes] [class-xii ]

• transposon
• phage DNA
• recombinant DNA
• host DNA
Correct Option: C  [ recombinant DNA ]

Remark: This new combination, created in vitro, is known as recombinant DNA.

When recombinant DNA is transferred into *Escherichia coli*, it replicates using the host’s _________ enzyme to make multiple copies.

[Biotechnology-Principles-and-Processes] [class-xii ]

• RNA polymerase
• DNA polymerase
• DNA ligase
• restriction enzyme
Correct Option: B  [ DNA polymerase ]

Remark: The transferred DNA replicates using the new host’s DNA polymerase enzyme.

The first basic step in genetically modifying an organism is the identification of DNA with _________.

[Biotechnology-Principles-and-Processes] [class-xii ]

• a palindromic sequence
• undesirable traits
• selectable markers
• desirable genes
Correct Option: D  [ desirable genes ]

Remark: The first basic step is the identification of DNA with desirable genes.

Maintenance of introduced DNA in the host and transfer of the DNA to its _________ is the final basic step in genetically modifying an organism.

[Biotechnology-Principles-and-Processes] [class-xii ]

• culture medium
• progeny
• cytoplasm
• bioreactor
Correct Option: B  [ progeny ]

Remark: The introduced DNA must be maintained and transferred to the progeny.

Besides restriction enzymes, polymerase enzymes, and ligases, the key tools of recombinant DNA technology include vectors and the _________.

[Biotechnology-Principles-and-Processes] [class-xii ]

• seaweed matrix
• thermostable protein
• host organism
• chromogenic substrate
Correct Option: C  [ host organism ]

Remark: The key tools include restriction enzymes, polymerase enzymes, ligases, vectors and the host organism.

The two enzymes responsible for restricting the growth of bacteriophage in *Escherichia coli* were isolated in the year _________.

[Biotechnology-Principles-and-Processes] [class-xii ]

• 1936
• 1963
• 1969
• 1972
Correct Option: B  [ 1963 ]

Remark: The two restriction enzymes were isolated in 1963.

The enzyme that cuts DNA, isolated in 1963, was called a restriction _________.

[Biotechnology-Principles-and-Processes] [class-xii ]

• exonuclease
• endonuclease
• ligase
• polymerase
Correct Option: B  [ endonuclease ]

Remark: The enzyme that cut DNA was called restriction endonuclease.

The first restriction endonuclease whose functioning depended on a specific DNA nucleotide sequence, isolated and characterized five years later (1968), was _________.

[Biotechnology-Principles-and-Processes] [class-xii ]

• EcoRI
• BamH I
• Hind II
• Sal I
Correct Option: C  [ Hind II ]

Remark: Hind II was the first restriction endonuclease characterized.