Nucleases fall into two broad categories:
A{'text': 'Exonucleases (cutting at ends) and endonucleases (cutting within)', 'label': 'A'}
B{'text': 'Ligases sealing gaps and polymerases building new strands', 'label': 'B'}
C{'text': 'Kinases adding phosphate and phosphatases removing phosphate', 'label': 'C'}
D{'text': 'Helicases unwinding DNA and topoisomerases relieving supercoil', 'label': 'D'}
Answer & Solution
Correct answer: A. {'text': 'Exonucleases (cutting at ends) and endonucleases (cutting within)', 'label': 'A'}
1. Nucleases are enzymes that cleave nucleic acids.
2. Exonucleases remove nucleotides one at a time from the ENDS of DNA/RNA.
3. Endonucleases make cuts at specific positions WITHIN a nucleic acid strand.
4. Restriction endonucleases are the palindrome-recognising cutters used in cloning.
_Source: NCERT Class 12 Biology, Ch 9 "Biotechnology: Principles and Processes", §9.2.1_
Related questions
ELISA works on the principle of interaction between antigen and:Adenosine deaminase is crucial for the functioning of the:That girl suffered a deficiency of:The first gene therapy patient was a girl aged:The first clinical gene therapy was given in the year:The insulin chains were produced in plasmids of:In which year was that done?Which company prepared the DNA sequences for human insulin?