Each restriction endonuclease recognizes a specific _________ nucleotide sequence in the DNA.

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

• repetitive
• palindromic
• random
• non-coding
Correct Option: B  [ palindromic ]

Remark: Restriction endonucleases recognize specific palindromic nucleotide sequences.

Restriction enzymes cut the DNA strands away from the center of the palindrome site, leaving overhanging stretches called _________.

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

• blunt ends
• sticky ends
• recognition loops
• restriction loops
Correct Option: B  [ sticky ends ]

Remark: The overhanging stretches are called sticky ends.

Sticky ends are named so because they facilitate joining by forming _________ bonds with their complementary cut counterparts.

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

• covalent
• ionic
• hydrogen
• peptide
Correct Option: C  [ hydrogen ]

Remark: Sticky ends form hydrogen bonds with their complementary cut counterparts.

Recombinant DNA molecules are composed of DNA from _________ sources/genomes.

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

• identical
• parental
• different
• single
Correct Option: C  [ different ]

Remark: Restriction endonucleases are used to form recombinant molecules composed of DNA from different sources/genomes.

The technique used to separate DNA fragments resulting from restriction endonuclease digestion is known as _________.

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

• PCR
• gel electrophoresis
• transformation
• downstream processing
Correct Option: B  [ gel electrophoresis ]

Remark: DNA fragments are separated by gel electrophoresis.

DNA fragments move towards the _________ under an electric field during gel electrophoresis because they are negatively charged molecules.

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

• cathode
• anode
• center
• magnetic pole
Correct Option: B  [ anode ]

Remark: Since DNA is negatively charged, it moves towards the positive electrode (anode).

The most commonly used matrix for gel electrophoresis is _________, a natural polymer extracted from sea weeds.

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

• polyacrylamide
• agarose
• cellulose
• starch
Correct Option: B  [ agarose ]

Remark: Agarose, extracted from sea weeds, is the most commonly used matrix.

In gel electrophoresis, DNA fragments resolve according to their size, meaning the _________ the fragment size, the farther it moves.

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

• heavier
• smaller
• denser
• larger
Correct Option: B  [ smaller ]

Remark: Smaller fragments move farther due to the sieving effect of the agarose gel.

Separated DNA fragments are visualized after staining with the compound known as _________.

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

• Bromophenol blue
• Ethidium bromide
• Crystal violet
• Coomassie blue
Correct Option: B  [ Ethidium bromide ]

Remark: DNA is stained with ethidium bromide for visualization.

Ethidium bromide stained DNA bands appear bright orange when exposed to _________ radiation.

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

• visible light
• infrared
• UV
• gamma rays
Correct Option: C  [ UV ]

Remark: Bright orange coloured bands are seen when the stained gel is exposed to UV light.