BamHI and HindIII are restriction enzymes. What determines where they cut the DNA?

BamHI and HindIII are restriction enzymes. What determines where they cut the DNA?

• A. Specific recognition sequences
• B. Random cleavage
• C. Cleave at any location if DNA is single-stranded
• D. Preference for GC-rich regions only

Answer: (A)

Restriction enzymes cut DNA only at particular DNA sequences they recognize. BamHI and HindIII are type II restriction enzymes that bind to their specific palindromic recognition sites and cleave within or very near those sites, producing predictable DNA fragments with overhangs or blunt ends. Because the cut happens at fixed positions relative to the recognized sequence, the location of the break is determined by the sequence itself, not by random chance or other features of the DNA. This is why the correct choice emphasizes specific recognition sequences. The other ideas don’t fit because the cuts aren’t random, they require double-stranded DNA with the specific recognition site, and their activity isn’t determined by GC content alone.

Restriction enzymes cut DNA only at particular DNA sequences they recognize. BamHI and HindIII are type II restriction enzymes that bind to their specific palindromic recognition sites and cleave within or very near those sites, producing predictable DNA fragments with overhangs or blunt ends. Because the cut happens at fixed positions relative to the recognized sequence, the location of the break is determined by the sequence itself, not by random chance or other features of the DNA. This is why the correct choice emphasizes specific recognition sequences.

The other ideas don’t fit because the cuts aren’t random, they require double-stranded DNA with the specific recognition site, and their activity isn’t determined by GC content alone.