Question 1

Which of the following is commonly used as a vector for cloning genes in higher plants?

Accepted Answer

Agrobacterium tumefaciens is a natural genetic engineer of plants. Its plasmid, known as the Ti plasmid (tumor-inducing plasmid), is widely used as a vector for delivering foreign genes into higher plants because it can naturally transfer a piece of DNA (T-DNA) into the host plant genome.

Question 2

Restriction endonucleases are enzymes that:

Accepted Answer

Restriction endonucleases are enzymes that inspect the DNA sequence, find specific recognition sites, and cut both strands of the DNA molecule at specific points, usually within or near the recognition sequence.

Question 3

The convention for naming restriction enzymes dictates that the first letter of the name comes from:

Accepted Answer

The convention for naming restriction enzymes states that the first letter of the name comes from the genus of the organism from which the enzyme is isolated, followed by the first two letters of the species name.

Question 4

During agarose gel electrophoresis, DNA fragments migrate towards the:

Accepted Answer

DNA fragments are negatively charged molecules due to the phosphate backbone. Therefore, when an electric field is applied across the agarose gel, they migrate towards the positively charged electrode, which is the anode.

Question 5

The staining dye used to visualize DNA fragments in an agarose gel under UV light is:

Accepted Answer

Ethidium bromide is the fluorescent dye commonly used to stain nucleic acids in agarose gels, which allows DNA fragments to be visualized under ultraviolet (UV) light as orange-colored bands.

Biotechnology: Principles and Processes — NCERT Class 12 Biology Important Questions & Revision Notes