AP BIOLOGY

Detailed explanation-1: -The sequence of the EcoRI restriction endonuclease is CTTAAG. Thus, the complementary recognition sequence for it will be GAATTC. It produces sticky ends in the cut segment. Hence, the right answer is option B.

Detailed explanation-2: -GAATTC is recognition site of restriction endonuclease EcoR I. EcoR I is the restriction enzyme, derived from Escherichia coli, strain R and is the first to be isolated. EcoR I recognizes and cuts at the specific restriction site 5’-GAATTC-3’ and produces sticky ends.

Detailed explanation-3: -EcoRI is a restriction enzyme that is derived from the bacteria E. coli. This restriction enzyme produces sticky ends when it cuts DNA at the restriction site. EcoRI recognizes a specific sequence on DNA: GAATTC.

Detailed explanation-4: -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. Other restriction enzymes, depending on their cut sites, can also leave 3’ overhangs or blunt ends with no overhangs.

Detailed explanation-5: -HaeIII cuts both DNA strands at the same location, resulting in blunt ends.