Genetic Modification Flashcards
What is genetic modification
-changing the genetic material of an organism by removing, changing or inserting individual genes from another organism
Advantages of genetic modification
-genes from different species can be combined, not restricted to alleles in natural population
-increase allele diversity, more disease resistance
DNA meaning
-molecule composed of two strands, coiled to form a double helix, the strands being linked by a series of paired bases
Proteins definition
Molecule made of amino acids, which could have one of man structural or functional roles in the body
Restriction endonucleases
Enzymes which act like molecular scissors to cut out the required gene
Gene
Section of the DNA which tells the cell to make a specific protein
DNA ligases
Enzymes that act like molecular glue to join cut DNA pieces back together
Transgenic
An organism which has ha genetic material from a different species transferred into its cells
What is recombinant DNA
DNA from one organism combines with the DNA from another organism
Vector
Structure which can be used to transfer genes in genetic engineering, such as plasmids
Steps for genetic modification
- Isolate plasmids from a bacterium
- Cut out the gene you want to insert from the human cell it is found in using restriction endonucleases
- Cut open the plasmid with restriction endonucleases
- Use DNA ligase to recombine the desired gene with the plasmid
- The recombinant plasmid is a vector, and is introduced into the bacteria
- It produces insulin now/whatever
Why do we use bacteria for insulin production
-no ethical issues
-same genetic code as organisms we take genes from (like humans for insulin), so they can ‘read’ it and produce the proteins
-they have plasmids
Insulin
-Hormone produced by the pancreas
-lowers blood glucose levels by stimulating cells to absorb glucose from blood
-converts excess glucose into glycogen
Encourages body to use glucose for energy instead of fats
How to genetically modify plants for resistance to pests
- Remove a plasmid from a bacterium and break it open using restriction endonucleases
- Use the same restriction enzymes to cut out a gene which codes for resistance to a pest
- Use dna ligase to insert desired gene and join these together
- Insert plasmid into the bacterium Agrobacterium
- This is a common vector which inserts plasmids into plant cells and results in plants containing the desired gene to pest resistance
- Agrobacterium does not affect cereals
- A gene gun can be used to fire DNA at new plant tissues and produce transgenic plants
Gene gun
-contain tiny pellets of gold coated with DNA that contains the desired gene
-fired directly into undifferentiated tissue
Why are Agrobacterium useful
-plants need to have billions of cells that have the new gene
-Agrobacterium can pass on genes from plasmids to plant cells
Pros and cons of using GM crops
+can tolerate bad conditions like infertile soil
+can produce plants with more nutrition
+improves crop yield
+less chemicals used, no bioaccumulation
-limited data on long term effect on human health
-GM crop seeds are more expensive, developing countries cannot afford them
-GM organisms can breed with wild organisms, their offspring can outcompete other plants, reducing biodiversity
