Ch. 12 DNA Technology + The Human Genome Flashcards
Recombinant DNA
DNA that has been genetically modified for variety
What are the 3 mechanisms for gene transfer?
1) Transformation
2) Transduction
3) Conjugation
Transformation
Taking up DNA from the fluid surrounding a cell
- incorporation of new genes into a cell from DNA that the cell takes up from the fluid around it
Transduction
Transfer of bacteria genes by phage virus
- DNA hidden by bacteria
- transfer of bacterial genes from one bacterial cell to another by a phage
Conjugation
Union of 2 cells in DNA transfer thru a mating bridge called pilus
- bacterial version of reproduction/mating
- the union (mating) of two bacterial cells or protist cells and the transfer of DNA b/w the two cells
What happens once bacterial DNA enters the cell?
It is integrated into the single circular chromosome
- crossing over allows for integration
- results in recombinant DNA
F Factor
Piece of DNA that makes conjugation possible
- F = fertilization
- carries genes for proteins of the bridge provides the site for the origin of replication
Plasmid
Small circular piece of DNA separate from the chromosome that is transferred in linear form
- found in prokaryotes
Vector
Plasma carrying extra genes
- in microbiology, a piece of DNA, usually a plasmid or a viral genome, that is used to move genes from one cell to another
R Plasmid
“Resistant”
- carry genes for enzymes that destroy antibiotics
- allows bacteria to transfer to to non-R-plasmid genes
- helps with genetic engineering
A bacterial plasmid that carries genes for enzymes that destroy particular antibiotics, thus making the bacterium resistant to antibiotics
How do you customize bacteria?
1) Isolate plasmid from the bacteria
2) Obtain the DNA from a gene of interest
3) Insert desired gene into plasmid = recombinant DNA
4) Bacteria cell takes up the plasmid
5) Genetically engineered bacteria is cloned
6) Regeneration of desired gene
7) Desired genes are removed and introduced to embryos
Biotechnology
Using organisms (microbes) to perform practical tasks - DNA technology
Restricted enzymes
Chop up foreign DNA there; restrict DNA from living in bacteria cell
A bacterial enzyme that cuts up foreign DNA, thus protecting bacteria against intruding DNA phages and other organisms; used in DNA technology to cut DNA molecules in reproducible ways
Sticky ends
Restriction sites exposed with DNA fragments
DNA ligase
Pasting enzyme
- catalyzes the formation of covalent bonds b/w adjacent nucleotides
An enzyme, essential for DNA replication that catalyzes the covalent bonding of adjacent DNA nucleotides; used in genetic engineering to paste a specific piece of DNA containing a gene of interest into a bacterial plasmid or other vector
Gene cloning
Production of multiple copies of a gene
Human Genome
Collection of all of the genetic material in a human cell
- 100,000 genes
Repetitive DNA
Many nucleotide sequences are repeated
What is type 1 of repetitive DNA?
Thousands of repetitive nucleotides
- long, near centromeres and tips of chromosomes
- support and structure
- maintains organization
What is type 2 of repetitive DNA?
Hundreds of repetitive nucleotides
- short and scattered
Transposons “Jumping Genes”
DNA segments that can move b/w chromosomes, change locations
- movement of DNA interrupts other genes
- natural mutagens
- “copy & paste” and “cut & paste”
Human Genome Project
International endevor to identify and map genes on chromosomes
What are the 3 methods of gene mapping?
1) Genetic (Linkage) mapping
- use data of genetic crosses to determine order of linked genes and relative distance
2) Physical mapping
- use restriction enzymes to break DNA into identifiable fragments that will then overlap
3) DNA Sequencing
- automatic DNA sequencing machines
What does mapping help to do?
Help w/ embryonic development, evolution, aging, diagnosis, treatment, prevention of diseases
Recombinant DNA Technology
Techniques for synthesizing recombinant DNA in vitro and transferring it into cells, where it can be replicated and may be expressed (genetic engineering)
Genomic Library
A set of DNA segments from an organism’s genome; each segment is eerily carried by a plasmid or phage
Probe
In DNA technology, a labeled single stranded nucleic acid molecule used to find a specific gene, or other nucleotide sequence, w/in a mass of DNA
Gel Electrophoresis
A technique for separating and purifying macromolecules; a mixture of molecules is placed on a gel between a positively charged electrode and a negatively charged on; negative charges on the molecules are attracted to the positive electrode and the molecules migrate toward that electrode; the molecules separate in the gel according to their rates of migration
Genetic Marker
An allele tracked in a genetic study; a specific section of DNA that earmarks a particular allele; may contain specific restriction sites (points where restriction enzymes cut the DNA) that occur only in DNA that contains the allele
Restriction fragments
Molecules of DNA produced from a longer DNA molecule, cut up by a restriction enzyme; used in RFLP (restriction fragment length polymorphism) analysis, genome mapping, and other applications
RFLP (restriction fragment length polymorphism)
Differences in homologous DNA sequences that are reflected in different lengths of restriction fragments produces when the DNA is cut up w/ restriction enzymes
- detects potential harmful alleles
Southern Blotting
A technique that reveals the presence of certain nucleotide sequences in a sample of DNA; after gel electrophoresis of the cut up DNA separates the fragments into bands, the DNA fragments are blotted onto a sheet of paper and then tested with a radioactively labeled nucleic acid probe
Polymerase Chain Reaction
A technique used to obtain many copies of a DNA molecule or part of a DNA molecule. A small amount of DNA mixed with the enzyme, DNA polymerase, DNA nucleotides, and a few other ingredients, replicates repeatedly in a test tube
- w/o living cells
Telomeres
Repetitive DNA at each end of a eukaryotic chromosome
DNA Fingerprint
An individual’s unique collection of DNA restriction fragments, deflected by electrophoresis and nucleic acid probes
Vaccine
A harmless variant or derivative of a pathogen used to stimulate a host’s organism’s immune system to mount a long term defense against the pathogen
Ti Plasmid
Bacterial plasmid that induces tumors in plant cells that it infects’ often used as a vector to introduce new genes into plant cells
Transgenic organism
An organism that contains genes from another species
Gene therapy
Alteration of afflicted individual’s genes
- could backfire b/x genetic variation needed
Eugenics
A socially rejected practice among humans of attempting to eliminate genetic disorders and “undesirable” inherited traits by selective breeding
