BIOL239 Lecture Notes - Lecture 8: Restriction Enzyme, Molecular Cloning, Cloning
Document Summary
Endonucleases, that exist in prokaryotes, function to recognize foreign dna sequences and cut them into pieces for further degradation by host exonucleases. Restricts what type of dna can exist in the host. E. coli will accept the entry of dna from other e. coli strains but will destroy dna from a phage. Recognize inverted palindromic sequences in dna. (each ren has a unique recognition sequence) When ren cut within these sequences, they leave either cohesive (sticky) or blunt ends. Cleavage ends: blunt, sticky 3" ends, sticky 5" ends (ends can be joined with other sequences and ligated) Recognition sites are always read 5" to 3". Electrophoresis is the movement of charged molecules in an electric field. Dna in a solution is weakly acidic (negatively charged) Larger fragments move more slowly through gel than smaller fragments. Wells are made in gel matrix, dna is loaded in, and a current is applied.