Genetic Engineering Flashcards
What is genetic engineering?
the modification of organisms by changing their genetic material; this can be the addition of genes from other species or the editing of genes that are already present
What is a transgenic organism?
an organism that contains genetic material into which DNA from an unrelated organism has been introduced
What is insulin?
a hormone used in the treatment of diabetes, is produced using genetically modified bacteria
What are Restriction endonucleases?
enzymes that cut DNA at specific sequences of nucleotides
What is a sticky end?
The small sections of single-stranded DNA that will bind to a complementary sequence left when restriction endonucleases cut the DNA
What is a DNA ligase?
an enzyme that joins the sugar– phosphate backbone of DNA.
What is dna ligase used for?
to ‘glue’ sections of DNA together
What is known as recombinant DNA?
DNA that is joined together
What are Plasmids?
small circles of DNA found in bacteria that can copy themselves within the bacteria
What is a vector?
a section of dna that is used to transfer dna from one organism to another
How can plasmids be used as vectors?
to transfer pieces of DNA from one cell to another.
What is a promoter?
a section of DNA that is often located at the front of a gene, responsible for switching the gene “on and off”
What does a promoter indicate?
the place where transcription (copying the gene) should start to make messenger RNA (mRNA)
Explain how Gene activity controlled by promoters
- The new gene may attach to the host cell DNA, but will do so in a random place.
- If this area is a ‘quiet’ region and, the rate of gene expression will be slow.
- In other parts of the host cell, DNA gene expression may be high.
Why would one want to make a transgenic fish?
- making models (organisms) for research in animal development and physiology
- making models (organisms) for medical research
- improving the yield of fish (AquAdvantage GM Salmon)
- producing disease-resistant fish
- detecting environmental pollution
- producing novelty pets.
What do atlantic salmon produce?
Atlantic salmon normally produce growth hormone only when the water temperature is warm
What have AquAdvantage salmon been genetically engineered to do?
to produce growth hormone all the time, so that it grows all year
What do AquAdvantage salmon contain?
a gene for the production of a growth hormone taken from a Chinook salmon
What is the gene contained in AquAdvantage salmon attached to?
a promoter from another species of fish, the ocean pout
What does the promoter from ocean pout ensure?
ensures that the gene for the production of growth hormone remains active, even at low temperatures, so that the genetically engineered salmon continue to grow all year round
What happens ot the promoter and growth hormone?
The promoter and growth hormone gene are joined together and placed into a plasmid vector, also cut with restriction endonucleases
How are DNA fragments joined?
using DNA ligase
Where are recombinant plasmids placed
into bacteria to manufacture large quantities of it
What happens to the recombinant plasmids?
The recombinant plasmids are then purified and microinjected into fertilised salmon eggs
What does the promoter sequence ensure?
ensures that the growth hormone gene is switched on constantly, so that the salmon grow throughout the year.
What are the advantages of genetic engineering for aquaculture?
- Rapid growth rate – allowing quick food production
- Improved product- in appearance and nutritional value
- Guaranteed availability of product
- Reducing the chance of depleting wild populations. (It may also be possible to apply the same technology to other species of fish, such as Tilapia, which are farmed in many countries around the world)
- Efficient energy Conversion – GM organisms could be developed that convert energy more efficiently, resulting in less food wastage. A reduction in food requirements would increase profit margins
What are the possible impact of the escape of genetically engineered species into the wild?
- risk of escape- concern they would quickly out-compete wild populations
- Risks to consumers- safety of the food not well studied (allergies possible, risk of genetic transfer to human or microorganisms, toxicity not known,
How can you reduce the risk of escape?
Salmon will be kept in tanks or enclosures to minimise escape
What is a precautionary principle?
A strategy that tries to ensure that all possible consequences of a new technology are considered before allowing it to be used
What is bioluminescence?
when a biological organism emits light
What is Biofluorescence?
incident light is re-emitted at a different, less energetic wavelength
What is a GFP?
Green Fluorescent Protein
What can a GFP do?
A GFP gene can be joined to a protein gene so that when the protein is made it will have GFP hanging off it
What are GFP’s used for?
- Tracing proteins
- Gene Markers
- Used to identify transgenic organisms
How can GFP’s trace proteins?
Individual proteins in human cells are too small to see even under a microscope, but the ways they form, fold and interact are essential to life and this can be traced with GFP
How can GFP’s be gene markers?
used in a bacterial plasmid to identify if the new gene was inserted successfully (usually the inserted gene disrupts the fluorescent gene and so the bacteria will no longer fluoresce)
How can GFP’s be used to identify transgenic organisms ?
It can be inserted along with the new section of DNA and then success can be determined by shining a light on the organism to see if it fluoresces
What does an engineered plasmid have?
several restriction sites where different enzymes can cut. Depending on the enzyme, the GFP gene will either be intact or disrupted
How can success of recombinant DNA be determined by?
Success of recombinant DNA can therefore be determined based on whether the bacterium glows or not
What is an AMP?
ampicillin resistant gene (antibiotic resistance)
