A palindrome in DNA is a sequence of base pairs that reads the same on the two strands when orientation of reading is kept the same, such as in the _________ direction.

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

• 5' $\rightarrow$ 3'
• 3' $\rightarrow$ 5'
• random
• reverse
Correct Option: A  [ 5' $\rightarrow$ 3' ]

Remark: The sequence reads the same on the two strands in the 5' $\rightarrow$ 3' direction.

One of the enzymes isolated in 1963 responsible for restricting bacteriophage growth in *E. coli* added _________ groups to DNA.

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

• phosphate
• methyl
• hydroxyl
• carboxyl
Correct Option: B  [ methyl ]

Remark: One of the enzymes isolated in 1963 added methyl groups to DNA.

The ability of restriction enzymes to leave sticky ends facilitates the action of the enzyme _________.

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

• DNA polymerase
• DNA ligase
• ribonuclease
• protease
Correct Option: B  [ DNA ligase ]

Remark: The stickiness of the ends facilitates the action of DNA ligase.

Unless one cuts the vector and the source DNA with the _________ restriction enzyme, the recombinant vector molecule cannot normally be created.

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

• different
• same
• blunt-end cutting
• random cutting
Correct Option: B  [ same ]

Remark: The vector and source DNA must be cut by the same restriction enzyme.

A high copy number plasmid vector would be preferred if one wants to recover _________ copies of the target DNA.

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

• fewer
• many
• purified
• stable
Correct Option: B  [ many ]

Remark: If one wants to recover many copies, the vector origin should support a high copy number.

The normal *E. coli* cells do not carry resistance against any of the common antibiotics used as selectable markers, such as ampicillin, tetracycline, etc., making them useful for identifying _________.

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

• recombinants
• non-transformants
• mutants
• transformants
Correct Option: D  [ transformants ]

Remark: The normal E. coli do not carry resistance, allowing selection of transformed cells.

The letter ‘rop’ in the vector pBR322 codes for the proteins involved in the _________ of the plasmid.

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

• ligation
• selection
• replication
• insertion
Correct Option: C  [ replication ]

Remark: rop codes for the proteins involved in the replication of the plasmid.

In insertional inactivation using the $\beta$-galactosidase gene, the $\beta$-galactosidase gene gets inactivated due to insertion of _________.

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

• the selectable marker
• alien DNA
• the origin of replication
• a promoter sequence
Correct Option: B  [ alien DNA ]

Remark: The gene is inactivated because recombinant DNA is inserted within its coding sequence.

To force bacteria to take up the plasmid, the bacterial cells must first be made ‘competent’ by treating them with a divalent cation such as _________.

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

• sodium
• potassium
• magnesium
• calcium
Correct Option: D  [ calcium ]

Remark: The divalent cation used is typically calcium.

The DNA coating micro-particles used in biolistics or gene gun methods for plants are made of gold or _________.

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

• platinum
• silver
• tungsten
• copper
Correct Option: C  [ tungsten ]

Remark: Cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA.