Question
Biology Question on recombinant technology
Restriction endonucleases are enzymes which
A
make cuts at specific positions within the DNA molecule
B
recognize a specific nucleotide sequence for binding of DNA ligase
C
restrict the action of the enzyme DNA polymerase
D
remove nucleotides from the ends of the DNA molecule.
Answer
make cuts at specific positions within the DNA molecule
Explanation
Solution
Restriction endonucleases were found by Arber in 1962 in bacteria. They act as 'molecular scissors' or chemical scalpels. They recognize the specific base sequence at palindrome sites in DNA duplex and cut its strands. For example, restriction endonuclease EcoRX found in the colon bacteria E. coli reocgnizes the base sequence GAATTC in DNA duplex and cuts its strands between G and A.