The modified cloning vector derived from *Agrobacterium tumifaciens* that is utilized to deliver genes of interest into a variety of plants is the:

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

• pBR322 plasmid
• Ti plasmid
• Pst I plasmid
• Col E1 plasmid
Correct Option: B  [ Ti plasmid ]

Remark: The tumor inducing (Ti) plasmid has been modified into a cloning vector which is no more pathogenic.

DNA cannot easily pass through cell membranes because it is a _________ molecule.

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

• Hydrophobic
• Hydrophilic
• Amphipathic
• Lipophilic
Correct Option: B  [ Hydrophilic ]

Remark: Since DNA is a hydrophilic molecule, it cannot pass through cell membranes.

To make bacterial cells competent to take up DNA, they are treated with a specific concentration of a divalent cation, typically:

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

• Sodium
• Potassium
• Magnesium
• Calcium
Correct Option: D  [ Calcium ]

Remark: Bacterial cells are treated with a specific concentration of a divalent cation, such as calcium.

What is the crucial temperature used during the brief heat shock step to enable competent bacteria to take up recombinant DNA?

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

• 0°C
• 37°C
• 42°C
• 100°C
Correct Option: C  [ 42°C ]

Remark: Cells are briefly placed at 42°C (heat shock) to force the bacteria to take up the recombinant DNA.

In which method is recombinant DNA directly injected into the nucleus of an animal cell?

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

• Biolistics
• Gene gun
• Micro-injection
• Heat shock
Correct Option: C  [ Micro-injection ]

Remark: Micro-injection involves directly injecting recombinant DNA into the nucleus of an animal cell.

The method suitable for plants where cells are bombarded with high velocity micro-particles coated with DNA is known as:

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

• Electroporation
• Biolistics or gene gun
• Micro-injection
• Chemical treatment
Correct Option: B  [ Biolistics or gene gun ]

Remark: Cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA in a method known as biolistics or gene gun.

The first step in the specific sequence of Recombinant DNA Technology processes is the:

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

• Fragmentation of DNA
• Ligation of DNA fragment into a vector
• Isolation of the genetic material (DNA)
• Isolation of a desired DNA fragment
Correct Option: C  [ Isolation of the genetic material (DNA) ]

Remark: Recombinant DNA technology involves several steps, the first of which is isolation of DNA.

To break open bacterial cells and release DNA, the enzyme used is:

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

• Cellulase
• Chitinase
• Lysozyme
• Protease
Correct Option: C  [ Lysozyme ]

Remark: Bacterial cells are treated with enzymes such as lysozyme.

To break open plant cells and release DNA, the enzyme used is:

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

• Lysozyme
• Cellulase
• Chitinase
• Ribonuclease
Correct Option: B  [ Cellulase ]

Remark: Plant cells are treated with enzymes such as cellulase.

To break open fungal cells and release DNA, the enzyme used is:

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

• Cellulase
• Lysozyme
• Chitinase
• Amylase
Correct Option: C  [ Chitinase ]

Remark: Fungal cells are treated with enzymes such as chitinase.