Question

Restriction enzyme $EcoRI$ cuts the DNA between bases $G$ and $A$ only when the sequence in DNA is

• A. GATATC
• B. GAATTC
• C. GATTCC
• D. GAACTT

Answer 1

The correct option is B GAATTC

In the laboratory, restriction enzymes (or restriction endonucleases) are used to cut DNA into smaller fragments. The cuts are always made at specific nucleotide sequences. Different restriction enzymes recognise and cut different DNA sequences.

EcoRI is a restriction enzyme that cleaves DNA double helices into fragments at specific sites. It is also a part of the restriction modification system. In molecular biology it is used as a restriction enzyme. EcoRI creates 4 nucleotide sticky ends with 5' end overhangs of AATT. The nucleic acid recognition sequence where the enzyme cuts is G/AATTC, which has a palindromic, complementary sequence of CTTAA/G.

So the correct option is 'GAATTC'.