Question

Match the following

Column Ⅰ	Column Ⅱ
A. Sticky ends	1. Recognition site
B. Exonuclease	2. Helps in hydrogen bond formation
C. Palindromic DNA sequence	3. Strain of the bacteria
D. ‘R’ in EcoRⅠ	4. Break the covalent bond

Choose the correct option

• A. A-2, B-2, C-4, D-1
  
• B. A-2, B-4, C-1, D-3
  
• C. A-1, B-4, C-2, D-3
  
• D. A-4, B-3, C-1, D-2
  

Answer 1

The correct option is B A-2, B-4, C-1, D-3


Sticky ends are produced by restriction enzymes when the cleavage point lies away from the axis of symmetry within the recognition site. This generates overhangs either at 5’ or 3’ ends. These are named sticky ends because they help in the formation of hydrogen bonds with their complementary cut counterparts.

Exonucleases remove nucleotides from the end of DNA by breaking the phosphodiester bond in the sugar-phosphate backbone.

Restriction endonuclease recognizes specific nucleotide sequences in a DNA molecule, often a palindrome, known as a recognition site.
Restriction endonuclease nomenclature consist of four parts:

• The first letter in a restriction endonuclease indicates the genus of the bacteria in its isolated from.
• The second two letters indicate the species.
• If a fourth letter is present, it indicates the strain of the bacteria.
• The Roman number at the end represents the order in which that particular restriction endonuclease was isolated from that strain of bacteria.