Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Biotechnology -Principles and Processes

Question:

Which of the following statements accurately describes restriction endonucleases?

 

Options:

They make cuts at random positions within the DNA molecule.

Restriction endonucleases recognize specific DNA sequences, known as restriction sites, and then cut the DNA at or near these sites.

They inhibit the action of the enzyme DNA polymerase.

All of these

Correct Answer:

Restriction endonucleases recognize specific DNA sequences, known as restriction sites, and then cut the DNA at or near these sites.

Explanation:

The correct answer is Option (2) -Restriction endonucleases recognize specific DNA sequences, known as restriction sites, and then cut the DNA at or near these sites.

The cutting of DNA at specific locations became possible with the discovery of the so-called ‘molecular scissors’– restriction enzymes. Restriction enzymes belong to a larger class of enzymes called nucleases. These are of two kinds; exonucleases and endonucleases. Exonucleases remove nucleotides from the ends of the DNA whereas, endonucleases make cuts at specific positions within the DNA

The first restriction endonuclease–Hind II, whose functioning depended on a specific DNA nucleotide sequence was isolated and characterized five years later. It was found that Hind II always cut DNA molecules at a particular point by recognizing a specific sequence of six base pairs. This specific base sequence is known as the recognition sequence for Hind II.

Restriction endonucleases are specialized enzymes that recognize specific DNA sequences, known as restriction sites, and then cut the DNA at or near these sites. They act like molecular scissors and can make cuts at precise positions within the DNA molecule. This ability to cleave DNA at specific sites is essential for various genetic engineering techniques, as it allows scientists to isolate and manipulate specific DNA fragments for various purposes.