Question

Which of the following options is correct for rDNA technology?
A. Endonuclease enzyme removes nucleotides from the ends if DNA
B. Exonuclease enzyme removes nucleotides from the site within DNA
C. Endonuclease enzyme cut the long palindromic DNA strand
D. Exonuclease enzymes remove nucleotides from the ends of the strand

Answer 1

Hint: Nucleases are enzymes that degrade nucleic acids by breaking the phosphodiester band that link one nucleotide to the next. Ribonucleases attack RNA and deoxyribonucleases attack DNA. Some nucleases will only attack single-stranded nucleic acids, others will only attack double-stranded nucleic acids and few will attack either kind.

Complete answer:
A. Endonuclease enzyme removes nucleotides from the ends of DNA: Endonucleases remove nucleotides one at a time from the end of DNA. Exonucleases can break internal phosphodiesterase bonds within a nucleic acid. Any particular exonuclease attacks either the 3’- end of the 5’-end but not both.
B. Exonuclease enzyme removes nucleotides from site within DNA: Nucleic acids and a few will attack either kind. Exonucleases and endonucleases are two different nucleases. Exonucleases remove nucleotides one at a time from the end of a nucleic acid whereas endonucleases can break internal phosphodiesterase bonds within a nucleic acid.
C. Endonuclease enzyme cuts long palindromic DNA strand: Exonuclease removes nucleotides one at a time from the end of a nucleic acid whereas endonuclease breaks internal phosphodiesterase bonds within a nucleic acid. Any particular exonuclease attacks either the 3’-end of the 5’-end but not both.
D. Exonuclease enzymes remove nucleotides from the ends of the strand: Nucleic acids and nucleic acids will attack either kind. Exonucleases and endonucleases are Nucleic different nucleases. Exonucleases remove nucleotides one at a time from the end of a nucleic acid whereas endonucleases can break internal phosphodiesterase bonds within a nucleic acid. Exonucleases cleave DNA sequences at palindromic sequences. They operate from either the 5’ or 3’ end one at a time.

Hence, the correct answer is option (D).

Note: DNA cutting enzymes are restriction enzymes. There are two types of enzymes. Endonucleases and exonucleases. Outer DNA sequences are removed by exonucleases. Endonuclease’s cuts at specific positions within DNA. Exonucleases, like endonuclease, is a hydrolyzing enzyme that cleaves the phosphodiester bond between the nucleotides. One of the important routes of RNA degradation in both races and eukaryotes is by the multiprotein exosome, it contains more than one exoribonucleases.