Genetic Technology Flashcards
Genetic engineering:
any procedure in which the genetic information in an organism is changed by altering the base sequence of a gene or by introducing a gene from another organism; the organism is then said to be a genetically modified organism (GMO)
Recombinant DND(rDNA):
DNA made by artificially joining together pieces of DNA from two or more different species
Transgenic organism:
any organism that contains
DNA from another source, such as from another individual of the same species or from a different species
genetically modified organism (GMO):
any organism that has had its DNA changed in a way that does not occur naturally or by selective breeding
Vector and examples:
a means of delivering genes into a cell used in gene technology;
plasmids and viruses and liposomes
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Unlike selective breeding, where whole sets of genes are involved, genetic engineering often results in the transfer of a single gene
restriction endonuclease (restriction enzyme):
an enzyme, originally derived from bacteria, that cuts DNA molecules; each type of restriction enzyme cuts only at a particular sequence of bases
Bacteriophage (phage):
a type of virus that infects bacteria; phages have double-stranded
DNA as their genetic material
Gene prob:
a length of single stranded DNA that has a complementary base sequence to another piece of DNA that you are trying to detect
Restriction enzymes either cut straight across the sugar-phosphate backbone to give………………. Or they cut in staggered fashion to give ……………..
Blunt ends
Sticky ends
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Bacterial DNA is protected from such an attack either by chemical alteration to the bases in DNA or by not having the target sites
These target sites or restriction sites are specific sequences of ……to…… bases.
4to6
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Many but not all restriction sites are palindromic(the sequence reads from both directions)
Finding the specific piece of DNA required involves separating the lengths of DNA using ……….and………
Gel electrophoresis and gene probes
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Multiple copies of the required piece of DNA can be made using the PCR(polymerase chain reaction)
Genome:
the complete set of genes or genetic material present in a cell or an organism; the genome of a eukaryote includes the DNA in the nucleus and in the mitochondria; the genomes of plants include chloroplast DNA
Polylinker:
Several single target sites for different restriction enzymes in a short length of DNA
Features of pUC group of plasmids:
1)low molecular mass so they are readily taken up by bacteria
2)an origin of replication so they can be copied
3)polylinker
4)one or more marker genes allowing identification of cells that have taken up the plasmid
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A small proportion of bacteria perhaps 1% take up plasmids with the gene and are said to be transformed
Liposomes:
Tiny spheres of lipid containing DNA
For The next step in the process is to get bacteria to take up the plasmids. First, the bacteria and plasmids are put into a solution with a high concentration of
Calcium ions
Promoter:
A length of DNA that includes the binding site for RNA polymerase where transcription of a gene or genes begins; in eukaryotes promoters also have sites for binding of transcription factors
Polymerase chain reaction (PCR):
an automated process that amplifies selected regions of
DNA using alternate stages of polynucleotide separation (denaturation of DNA) and DNA synthesis catalysed by DNA polymerase
Summary of PCR process:
- DNA is heated briefly to denature the DNA, which separates the double helix.
- Primer DNA added after cooling.
Complementary base pairing occurs. - DNA polymerase uses free dNTPs to synthesise complementary strands of DNA.
- The length of DNA has been copied and forms part of two
DNA molecules.
DNA hybridization:
binding together of two molecules of single-stranded DNA by complementary base pairing
DNA is negatively charged because of….
Phosphate groups in the phosphate-sugar backbone
Types of gels in gel electrophoresis:
1.polyacrylamide:used for separating small fragments of DNA
2.agarose(a kind of polysaccharide produced from seaweed): used for separation of fragments that are between 100 base pairs and 50000 base pairs in length.
VNTRs(mini satellites):
have base sequences of between 10 to 100 base pairs in length that are repeated between 5 and 50 times.
They were used in the first form of genetic fingerprinting to give the ladder-like bands on gel
STR(micro satellites):
Short tandem repeats. STRs are repeated sequences of nucleotides which are much shorter than minisatellites. STRs are composed of 2 to 5 nucleotides which are repeated 10 to 30 times. One STR has the base sequence CACACA repeated between 5 and 20 times. As with minisatellites, the number of repeats in any one STR is variable.
