Zoology - Biotechnology - Principles and Processes Question with Solution | TestHub
Which of the following statements arenottrue regarding restriction endonucleases ?
A. They are called molecular scissors.
B. These are the enzymes responsible for restricting the growth of bacteriophages inE. coli.
C. They cut the DNA only at the centre of the palindromic sites.
D. They remove nucleotides only from the ends of DNA fragments.
E. They recognise specific palindromic base-sequences.
Choose the answer from the options given below :NEET 2026 (Cancelled)
Options:
Answer:
Solution:
Restriction endonucleases are commonly known as molecular scissors as they cut DNA at specific locations. Thus, statement A is true.
They were discovered for their ability to restrict the growth of bacteriophages in bacteria such asE. coli. Thus, statement B is true.
Restriction endonucleases cut the DNA helix a little away from the centre of the palindromic sites, but between the same two bases on the opposite strands. Thus, statement C is incorrect.
Exonucleases remove nucleotides from the ends of the DNA, whereas endonucleases make cuts at specific positions within the DNA. Thus, statement D is incorrect.
They function by inspecting the length of a DNA sequence and bind to the DNA to cut each of the two strands of the double helix at specific points in their sugar-phosphate backbones, recognising specific palindromic nucleotide sequences. Thus, statement E is true.
Therefore, statements C and D are not true.
Answer: C and D only
