Unit 6 Flashcards
recombinant DNA
fragment of DNA composed of sequences originating from at least two different sources
restriction endonucleases
enzymes that are able to cleave double-stranded DNA into fragments at specific sequences; also known as restriction enzymes
recognition site
a specific sequence within double-stranded
DNA, usually palindromic and consisting of four to eight nucleotides, that a restriction endonuclease recognizes and cleaves
sticky ends
fragment end of a
DNA molecule with short single-stranded overhangs, resulting from cleavage by a restriction enzyme
blunt ends
fragment ends of a
DNA molecule that are fully base paired, resulting from cleavage by a restriction enzyme
methylases
enzymes that add a methyl group to one of the nucleotides found in a restriction endonuclease recognition site, altering its chemical composition
methyl group
CH3
T4 DNA ligase
an enzyme used to join together DNA blunt or sticky ends
gel electrophoresis
separation of charged molecules on the basis of size by sorting through a gel meshwork
agarose
gel-forming polysaccharide found in some types of seaweed that is used to form a gel meshwork for electrophoresis
polyacrylamide
artificial polymer used to form a gel meshwork for electrophoresis
ethidium bromide
a carcinogenic, flat molecule that inserts itself among the rungs of the ladder of DNA and fluoresces under UV light
fluoresces
glows under UV light because of the excitation of a molecule’s electrons
plasmids
small circular pieces of DNA that can exit and enter bacterial cells
copy number
number of copies of a particular plasmid found in a bacterial cell
multiple-cloning site
region in plasmid that has been engineered to contain recognition sites of a number of restriction endonucleases
cloned
a fragment of DNA that has been introduced into a foreign cell, resulting in exact copies of the original DNA fragment being made when the foreign cell replicates and divides
transformation
introduction of foreign DNA, usually by a plasmid or virus, into a bacterial cell
vectors
vehicles by which DNA may be introduced into host cells