Question

Restriction endonucleases are enzymes which

• A. Restrict the action of the enzyme DNA polymerase
• B. Remove nucleotides from the ends of the DNA molecule
• C. Make cuts at specific positions within the DNA molecule
• D. Recognize a specific nucleotide sequence for binding of DNA of ligase

Answer 1

Answer: (C)

Make cuts at specific positions within the DNA molecule

Restriction endonucleases recognize specific sequences in the DNA to it into fragments, not to bind the DNA to ligase. The specific sites are 4-6 bp long and are called as restriction sites. Each restriction endonuclease has a specific restriction site. Exonucleases enzymes remove nucleotides one at a time from the end of a polynucleotide chain. They shorten the DNA by one nucleotide at a time, they do not digest it into fragments. DNA polymerase is an enzyme that copies the template DNA strand into daughter DNA through replication. It extends the primer into DNA strands; restriction enzymes do not affect its activity. Correct option is C.