The step known as _________ involves cutting out the separated bands of DNA from the agarose gel and extracting the DNA fragments.

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

• ligation
• elution
• spooling
• denaturation
Correct Option: B  [ elution ]

Remark: Elution is the process of extracting the purified DNA fragments from the gel piece.

Plasmids and bacteriophages used as cloning vectors have the ability to replicate within bacterial cells _________ of the control of chromosomal DNA.

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

• dependent
• independent
• simultaneously
• synergistically
Correct Option: B  [ independent ]

Remark: Plasmids and bacteriophages replicate independent of chromosomal DNA.

Some plasmids may have 15-100 copies per cell, but bacteriophages typically have very high _________ of their genome within the bacterial cells.

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

• size
• copy numbers
• restriction sites
• mutation rates
Correct Option: B  [ copy numbers ]

Remark: Bacteriophages have very high copy numbers of their genome.

The sequence in a vector responsible for initiating replication and controlling the copy number of the linked DNA is the _________.

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

• selectable marker
• cloning site
• origin of replication (ori)
• rop gene
Correct Option: C  [ origin of replication (ori) ]

Remark: Ori is responsible for initiating replication and controlling the copy number.

A selectable marker helps in identifying and eliminating _________ and selectively permitting the growth of the transformants.

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

• recombinants
• non-transformants
• competent cells
• viruses
Correct Option: B  [ non-transformants ]

Remark: Selectable markers help in eliminating non-transformants.

The procedure through which a piece of DNA is introduced into a host bacterium is called _________.

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

• elution
• cloning
• transformation
• ligation
Correct Option: C  [ transformation ]

Remark: Transformation is the procedure through which DNA is introduced in a host bacterium.

Genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline or _________ are considered useful selectable markers for E. coli.

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

• penicillin
• streptomycin
• kanamycin
• cycloserine
Correct Option: C  [ kanamycin ]

Remark: Kanamycin is listed as a useful selectable marker.

To facilitate linking alien DNA, a vector needs to have very few, preferably _________, recognition sites for commonly used restriction enzymes.

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

• multiple
• single
• variable
• palindromic
Correct Option: B  [ single ]

Remark: Presence of more than one site complicates gene cloning, so single sites are preferred.

The ligation of foreign DNA in the vector pBR322 is often carried out at the BamH I site present in the _________ resistance gene.

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

• ampicillin
• chloramphenicol
• tetracycline
• kanamycin
Correct Option: C  [ tetracycline ]

Remark: Foreign DNA can be ligated at the BamH I site of the tetracycline resistance gene.

If foreign DNA is inserted into the tetracycline resistance gene of pBR322, the recombinant plasmids will lose tetracycline resistance due to _________.

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

• mutation
• loss of ori
• insertional inactivation
• non-transformation
Correct Option: C  [ insertional inactivation ]

Remark: The loss of function due to insertion of foreign DNA is insertional inactivation.