Question

Which of the following cuts the DNA at specific places?

• A. Exonuclease
• B. Ligase
• C. Restriction endonuclease
• D. Alkaline phosphatase

Answer 1

The correct option is C

Restriction endonuclease

The correct option is C.

Explanation of the correct option:

1. Restriction Endonucleases identify specific nucleotide sequences known as recognition or restriction sites and cleave the DNA into fragments.
2. The restriction sites are particular sites that are 4-6 bp long.
3. Example - EcoRI and HindII.

Explanation of the incorrect options:

Option A:

1. Exonucleases are enzymes that remove nucleotides from the end of a polynucleotide chain one at a time.
2. They cut the DNA one nucleotide at a time, rather than digest it into fragments.

Option B:

1. The hydrolase enzyme is alkaline phosphate.
2. They sever the strands of DNA duplex after recognizing the specific base sequence at palindrome locations.

Option D:

1. These enzymes are responsible for removing phosphate groups from a wide range of compounds, including nucleotides, proteins, and alkaloids.
2. ATP phosphate, for example, takes one phosphate from ATP and converts it to ADP.

Final answer: Restriction endonuclease cuts DNA at specific places.