1.28 Biotechnology Flashcards
Describe how particular genes can be removed
using restriction enzymes and identified using probes.
- Restriction enzymes cut DNA at highly specific regions.
- The same restriction enzyme used produces fragments that are cut at the same sequence of
nucleotides. - The sequence that is recognized by a restriction enzyme is called a
restriction site.
Describe how particular genes can be removed
using restriction enzymes and identified using probes.
- Once the DNA of interest has been extracted and cut into fragments the gene of
interest needs to be identified and isolated by a gene probe. - A probe is a short piece of single-stranded DNA or RNA that has a complimentary
sequence to the gene of interest. - The radioactievely or fluorelabelled probes
- A solution containing the DNA of interest, and the selected gene probes is then heated, separating the DNA and allowing probes to bind to the DNA fragments.
- those lit up proves can now be used to isolate the gene
Describe how selected genes can be
transferred between species. (Bacterial Plasmids)
Plasmids can be isolated, and then cut using a specific restriction enzyme.
Human DNA containing a gene of interest is cut using the same restriction enzyme.
The human gene and plasmids are then mixed, and the human DNA gets
inserted into the plasmid
Describe how selected genes can be
transferred between species. (Virus)
Viruses are very small, non-cellular particles made up of a nucleic acid core
(DNA or RNA), and a protein coat.
Viruses can introduce their genetic material into a host cell, causing it to manufacture viral proteins, and produce new virus particles.
Viruses can be modified so that they carry a desired gene, but not have the
ability to harm the host cell.
Altered viruses are used to “infect” cells with the desired gene, which can be
incorporated into the cell’s DNA
Describe how selected genes can be
transferred between species. (Microinjection)
In animals, the desired gene can be inserted into a fertilised ovum by
micro-injection.
The ovum is held in place and a glass micropipette is passed through the
cell membrane and into the nucleus.
The desired gene is then injected into the nucleus.
This technique has limited success and is still being refined.
what are bacterial plasmids and what is the
small rings of DNA that
are separate from the bacterial chromosome
- Bacterial plasmids are a particularly successful method for genetic modification
Bacterial plasmids continued
DNA ligase is used to rejoin the plasmids into rings.
The recombinant plasmids are then mixed with bacterial cells, which can take up the plasmids
The human gene of interest is now incorporated into the bacterial cells, and each time the bacteria cell divides, the human gene is also copied.
This is called gene cloning.
The bacteria will also express the human gene, and make human proteins,
such as insulin and growth hormone
