BIOL 1010 Lecture Notes - Lecture 4: Restriction Enzyme, Recognition Sequence, Endonuclease
5 Nov 2018
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Document Summary
They are (typically) circular double stranded dna molecules (1 to over 400 kilo-basepair) that are separate from the chromosomal dna. there are from one copy, for large plasmids, to hundreds of copies for small plasmids present in a single cell. Plasmids can replicate independently but which cannot integrate into the host chromosome. #the main thing that is new with genetic engineering is that species barriers can now readily be bridged (recombinant dna methods). Dna molecule produced arti cially and containing sequences from unrelated organisms. Endonucleases are enzymes that cleave double stranded dna at a particular recognition sequence by cutting the sugar-phosphate bond speci cally between two nucleotides. In 1970 it was accidentally found that haemophilus in uenzaera broke down foreign dna. The puri ed enzyme called hindii broke down (digested) e. coli dna but not the h. in uenza"s dna. Restriction enzymes cleave to leave either a sticky end or a blunt end.
