NEETZoologyBiotechnology - Principles and Processes
The restriction endonuclease EcoRI recognizes the palindromic sequence 5'-GAATTC-3'. Which of the following accurately describes its cleavage action on this sequence?
Options
- AIt cuts exactly at the centre between A and T by breaking phosphodiester bonds.
- BIt cuts between G and A by breaking hydrogen bonds.
- CIt cuts between A and T by breaking hydrogen bonds.
- DIt cuts between G and A by breaking phosphodiester bonds.
Correct answer
D. It cuts between G and A by breaking phosphodiester bonds.
Step-by-step solution
EcoRI recognizes the palindromic sequence 5'-GAATTC-3'. It cuts the DNA strand a little away from the centre of the palindrome site, specifically between the bases G and A on both the strands. The enzyme achieves this by cleaving the phosphodiester bonds of the sugar-phosphate backbone. It does not break hydrogen bonds directly; rather, the hydrogen bonds between the complementary bases of the sticky ends separate subsequently. Therefore, the correct action is cutting between G and A by breaking phosphodiester bond