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Unformatted text preview: work as vectors?
Why do viruses work as vectors?
Plasmids are small, circular pieces of DNA outside the bacterial chromosome. They can reproduce
independently of the chromosomes, and carry genes that are beneficial (but not necessary) the cell in
which they reside. They work as vectors because they infect cells and they just implant DNA in the
What are the steps involved in cloning a gene into bacteria?
● Isolate the DNA from the organism that contains the desired gene
● Fragment DNA using a restriction enzyme to produce DNA pieces with cohesive (“sticky”)
● DNA fragments are incorporated into plasmids (The type of plasmid used for cloning has a
single restriction site, and when cleaved by the restriction enzyme, generates the same
cohesive ends that are in the fragments of the DNA to be cloned.)
● Cohesive ends of the plasmid and DNA fragments line up, and the enzyme DNA ligase is used
to form phosphodiester bonds which seal up the backbone of the plasmid
● The plasmids are incorporated into bacterial host cells by transformation.
For what purposes are genes cloned in bacteria?
The gene for insulin can be cloned to make insulin for diabetes patients, proteins that could be used
in vaccines, Human Growth Hormone
How would you clone a gene into an animal or plant? For what purposes?
You would insert the gene into the zygote of the animal. This can be used to create transgenic animals
that can be used for research or consumerism (fluorescent fish).
What are some examples of genes cloned into animals and plants?
gene for fluorescence in fish, cats, and rabbits
How are transgenic animals valuable for scientific research?
Animal models are genetically engineered to carry disease-causing mutations in their genes, so
scientists can use them for gene therapy research.
What are the concerns about genetically modified foods?
It may not be healthy for our bodies, it could cause allergic reactions, it can harm other naturally
occurring organisms, crop plants engineered for herbicide tolerance and weeds can cross-breed, 11 resulting in the transfer of the herbicide resistance genes from the crops into the weeds, introduced
genes may cross over into non-modified crops planted next to GM crops.
What are the concerns about genetically modified animals?
It can hurt the animal, it is “playing God,” the food produced within them could be unsafe, can
genetic modifications be patented?
What is somatic cell nuclear transfer (the technique used to clone an animal)? How
does it work?
1. You would take a somatic cell from the creature you plan to clone and extract the cell’s nucleus. \
2.They then remove the nucleus of an egg cell and insert the somatic cell nucleus in its place.
3.Next, they treat the reconstructed egg with electricity to stimulate cell division.
3. If the egg divides normally and forms a blastocyst (a small clump of cells that forms after an egg is
fertilized), scientists will transfer it into the uterus of a surrogate mother to develop into a new
Has a human ever been cloned?
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