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
host cell
a cell that has taken up a foreign plasmid or virus and whose cellular machinery is being used to express the foreign DNA
competent cell
a cell that readily takes up foreign DNA
restriction endonuclease
Use: bacterial enzyme that cleaves
DNA sequences at a specific recognition site
methylase
bacterial enzymes that add a methyl group to recognition sites to protect DNA from cleavage by restriction enzyme
DNA ligase
enzyme that joins complementary fragments by reconstituting phosphodiester bond of DNA backbone
gel electrophoresis
process by which DNA fragments of different lengths are separated by electrical current, negative charge of DNA, and constant charge-to-mass ratio
plasmid
small circular DNA that has the ability to enter and replicate in bacterial cells and, therefore, can be used as a vector to introduce new genes into a bacterial cell
polymerase chain reaction
(PCR)
amplification of DNA sequence by repeated cycles of strand separation and replication
DNA primers
short sequences of
DNA nucleotides that are complementary to the opposing 3’-to-5’ ends of the DNA target sequence that is to be replicated
Taq polymerase
DNA polymerase, extracted from Thermus aquaticus, that is able to withstand high temperatures
Thermus aquaticus
species of bacteria found in hot springs
variable-length strands
mixture of strands of DNA that have been replicated and are of unequal length
constant-length strands
mixture of strands of DNA that have been replicated and are of equal length
polymorphism
any difference in
DNA sequence, coding or non-coding, that can be detected between individuals
restriction fragment length polymorphism (RFLP) analysis
a technique in which DNA regions are digested using restriction endonu-clease(s) and subiected to radioactive complementary DNA probes to compare the differences in DNA fragment lengths between individuals
Southern blotting
a procedure that allows the DNA in an electrophoresis gel to be transferred to a nylon membrane while maintaining the position of the DNA band fragments
hybridization
complementary base pairing between strands of nucleic acids via hydrogen bonding
autoradiogram
gel pattern imprinted on X-ray film by radioactive probes
Sanger dideoxy method
DNA sequencing technique based on
DNA replication that uses dideoxy nucleoside triphosphates
dideoxy analogue
nucleoside triphosphate whose ribose sugar does not possess a hydroxyl group on the 2’ and the 3’ carbon
genetic screening
process by which an individual’s DNA is scanned for genetic mutations
gene therapy
the alteration of a genetic sequence in an organism to prevent or treat a genetic disorder
pronociceptive transmitters
signal molecules that amplify pain sensation via a neurological pathway
antinociceptive transmitters
signal molecules that dampen pain sensation via a neurological pathway
antisense oligonucleotides
complementary DNA or RNA that anneals to mRNA and inhibits
transgenic
organism in which foreign DNA has been artificially incorporated into its genome
Ti plasmid
plasmid, found in Agrobacterium tumefaciens bacteria, that is able to enter plant cells
Agrobacterium tumefaciens
type of bacteria that infects wounded plant cells and creates a crown gall
Bt toxin
poisonous substance produced by Bacillus thuringiensis, which acts as a natural herbicide
DNA fingerprinting
pattern of bands on a gel, originating from RFLP analysis or PCR, that is unique to each individual
