What is a recognition site in biology ?

Restriction enzyme :

1. The restriction enzyme cleaves the DNA sequence asymmetrically to produce short and single-stranded structures which are called sticky or cohesive ends.
2. A restriction enzyme recognizes a palindromic sequence (a sequence of base pairs that reads the same on two strands of DNA) in the DNA to cleave it.
3. The restriction enzyme can cleave the DNA from the terminal (exonuclease) or within the DNA sequence(endonuclease)
   

Recognition site :

1. In biology recognition site is the site recognized by a restriction enzyme to cleave DNA is called a recognition site.
2. These sites are located on a DNA molecule containing specific sequences of nucleotide (4-8 base pair)

Example: The restriction enzyme ECOR1 cleaves the DNA by recognizing a 6-base pair recognition site (GAATTC).