Genetic Engineering Flashcards
What is genetic engineering?
When you isolate a gene for a desirable characteristic in one organism and placing it in another organisms, using a suitable vector.
How is genetic engineering possible using the genetic code?
Because it is universal so that almost every organism uses the same four bases and the same codons code for the same amino acids in all living things, so genetic information is transferable between species.
What does it mean when an organism is transgenic?
When it contains nucleotide sequences from a different species.
What is a genetically modified organisms (GMO)?
Any organism that has introduced genetic material.
What is recombinant DNA?
The transfer of fragments of DNA from one organism/species into another organism/species, this organism then contains recombinant DNA and will be a GMO.
What are 3 uses of genetic engineering?
- Genetic modification of crops to increase crop yield through resistance to drought, disease, pesticides and herbicides; or to provide increased nutritional value.
- Genetic modification of livestock to give disease and pest resistance and increased productivity.
- Genetic modification of bacteria to produce medicines like insulin.
Why is it much harder to engineer the DNA of eukaryotic animals?
Because animal cell membranes are a lot more difficult to manipulate than plant cell membranes.
What are the overall steps to genetically engineer an organism?
- Identify the desired gene (insulin).
- Isolation of the desired gene fragment.
- Multiplication of the DNA fragment.
- Transfer into the organism using a vector. Electroporation is used to encourage uptake of plasmid vectors.
- Identification of the cells with the new DNA fragment using a marker which is then cloned.
What are 2 ways in which a desired gene is isolated in genetic engineering?
- Restriction endonucleases:
- used to cut genes at specific base sequences (restriction sites). Different restriction enzymes cut at different restriction sites. Most restriction endonucleases cut the two DNA strands unevenly, leaving one of the strands of the DNA fragment a few bases longer than the other strand. These regions with unpaired, exposed bases are called sticky ends. - Reverse transcriptase:
- used to build double stranded DNA from single stranded RNA.
What is an advantage of sticky ends produced from restriction endonucleases?
They make it much easier to insert the desired gene into the DNA of a different organism.
What is an advantage of isolating a desired gene using reverse transcriptase?
It makes it easier to identify the desired gene, as a particular cell will make some very specific types of mRNA.
How can we multiple the desired gene in step 3 of genetic engineering?
Using PCR which amplifies the DNA (method in another flashcard deck).
How do we transfer the desired gene into an organism using a vector?
- Vectors are used to deliver DNA fragments into a cell, e.g. a plasmid.
- The plasmids that are used by vectors contain a marker gene.
- To insert the DNA fragment into a plasmid, it must be cut open using restriction endonucleases which then leaves complementary sticky ends on the plasmids to the complementary sticky ends on the DNA fragment.
- DNA ligase forms phosphodiester bonds between the sugar and the phosphate groups on the two DNA strands, joining them together.
What are marker genes?
An additional gene inserted into a plasmid that is used to aid in the identification of host cells that have taken up the desired gene as they code for identifiable substances that can be tracked.
What are 3 types of marker genes?
- Fluorescent markers which flouresces under UV light.
- Enzyme markers which transforms colourless or non-fluorescent substrates into products that are coloured or fluorescent.
- Antibiotic resistance marker genes.
