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Question
Which of the following enzymes catalyse the removal of nucleotides from the ends of DNA?
Options
Endonuclease
Exonuclease
DNA ligase
Hind - II
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Solution
Exonuclease
Explanation:
The enzyme that catalyzes the removal of nucleotides from the ends of DNA is exonuclease. Exonuclease specifically removes nucleotides one by one from the ends of a DNA strand, whereas endonucleases cut DNA at internal sites. DNA ligase joins DNA fragments but does not remove nucleotides. Hind II is a type of restriction endonuclease that cuts DNA at specific internal sequences, not at the ends.
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\[\ce{5' C - T - G - C - A \overset{\downarrow}{-}{G 3'}}\]
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