Question

Study the sequence of bases in a DNA molecule that is shown below and answer the questions.

5'-GAATTC-3'

3'-СТТАAG-5'

1. What are such sequences called? Name the enzyme used that recognises such nucleotide sequences.     [1]
2. How do these enzymes function?     [1]

Answer 1

1. Sequence Identification and Enzyme Name
   • Name of sequence: These are called Palindromic Nucleotide Sequences. In DNA, a palindrome is a sequence of base pairs that reads the same on both strands when the reading orientation (5' to 3') is kept the same.
   • Enzyme: The enzymes that recognise these specific sequences are Restriction Endonucleases. Specifically, the sequence 5'-GAATTC-3' is recognised by the enzyme EcoRI.
2. Mechanism of Function
   • Binding and Cutting
   • Specific Cleavage
   • Sticky Ends