Recombinant DNA and Genetic Engineering Flashcards
(40 cards)
Genetic engineering-
modifying the DNA of an organism to new genes w new traits
Biotechnology-
use of organisms to benefit humanity
Recombinant DNA technology-
researchers splice together DNA
from different organisms
steps and info recombinant DNA tech
Scientists introduce foreign DNA into the cells of microorganisms; When cell divides, the foreign DNA is replicated and transmitted to daughter cells; DNA sequence is therefore cloned to provide millions of identical copies
geneticists cut both foreign DNA and plasmid DNA with the same restriction enzyme. The two types of
DNA are mixed together and combined
Restriction enzymes
are used to cut DNA molecules only in specific places; Each enzyme recognizes and cuts the DNA at different site; Many cut at palindromic sequences; Cuts both strands, but in a staggered fashion- produces
sticky ends; If sticky ends of two molecules are put together, they are sealed by DNA ligase
origin of restriction enzymes
Derived from bacteria cells, which use these enzymes as defense against viral DNA
palindromic sequences-
base sequence of one strand reads the same as its complements when both are read in the 5’ to 3’ direction
sticky ends-
tails which can base pair with a complementary
tail of any other DNA fragment or molecule cut by the same restriction enzyme
Plasmid-
very small circle of extra DNA found in bacterial cells that has a few genes and is replicated along w the other bacterial DNA.
Transformation
DNA (plasmids) from one cell can be taken up by other bacterial cells; Useful to bacteria because it can offer resistance to antibiotics
vector
carrier capable of transporting a DNA fragment into a cell. plasmids, viruses, etc.
vector capabilities
Vector can only carry a certain size of DNA fragment
smaller than 10 kb E. coli, up to 23 kb bacteriophage
recombinant tech diagram
vector page
Genomic library-
collection of thousands of DNA fragments that
represent all the DNA in a genome
Genomic library- process
Each fragment from genomic library is inserted into a plasmid, which also
contains the gene for
antibiotic resistance
• Plasmid is then inserted into
bacterial cell
• Cells are incubated on a medium containing antibiotics, so those bacteria that do not contain the plasmid will die, while those that incorporated the plasmid will grow
• Entire genome is therefore stored in collection of
recombinant bacterial cells
Genomic library- diagram
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Chromosome library-
containing all DNA fragments of a specific chromosome
cDNA library-
contains DNA derived
from mRNA after processing- does not contain introns
cDNA
complementary DNA
cDNA diagram
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genetic probe
To find a gene of interest in a library, a genetic probe is used- radioactively labeled segment of single-stranded DNA that can hybridize, or base-pair, to complementary sequences in the target gene
genetic probe diagram
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Polymerase Chain Reaction (PCR) purpose
Can amplify a tiny sample of DNA millions of times in a few
hours (discovered in 1985)
Polymerase Chain Reaction (PCR) process
done in a thermocycler
Mix together sequence of DNA, primers, nucleotide bases, and a special polymerase called Taq polymerase which does not denature in heat
• Heat and cool mixture over and over, allowing the DNA strands to separate and copy
- DNA doubles with every cycle, so after only 20 cycles, over 1m copies are made