Recombinant DNA Flashcards
Recombinant DNA technology
Involves the introduction of foreign DNA into a cell, Genes from one organism are added to the chromosomes of another organism
Potential of rDNA
Enormous potential to replace faulty genes with healthy genes, Cells used in rDNA can’t be reinserted into a human (would give them a disease) but is instead used to produce a certain protein which can be collected and given to humans (E.g insulin)
Restriction enzymes
Able to cut up a piece of DNA, Cut the DNA from the donor genome to expose the gene of interest and cuts the DNA of the vector so that the gene of interest can be inserted
Types of restriction enzymes
Sticky end (single ends, best), Blunt end
Recognition site
Sequence of bases where the restriction enzyme always cuts
Vectors
Bacteriophage or virus is used to transfer genetic material from one cell to another, E.g plasmids, viruses
Role of vectors
Introduce desired genetic material to the host cell and increase the amount of desired DNA in the host cell
Bacteriophages/phages
Rarely used for rDNA techniques, Viruses that infect bacterial cells, The viruses DNA is cut and the gene of interest is inserted into the virus’s DNA, Viruses are used as a vector to introduce genes to a cell’s DNA
Plasmids
Circular strands of DNA found within bacteria, Capable of self-replication which is an advantage as it means plasmids hold more genetic information than a bacteriophage (amplifies amount of DNA available), Can be cut by a restriction enzyme and have the desired genes placed back into the bacteria
DNA ligase (glue)
Enzyme that is capable of joining or recombining pieces of DNA
Ligation
Process where pieces of DNA are joined together by DNA ligase
rDNA main steps
Isolate the desired gene, Insert the gene into the vector and clone it, Large quantities of the vector are introduced to the selected host cell
Production of insulin using rDNA
Identify the gene of interest (gene that codes for the protein insulin), Gene of interest is removed from the donor cell (beta cells in the islets of Langerhans in the pancreatic cell of a healthy person) using a restriction enzyme, Vectors (plasmid removed from bacterium) are cut using the SAME restriction enzyme, Gene is inserted into the plasmid and combined through ligation, Plasmid is reinserted back into the bacterium which undergoes mitosis, Bacterium (transgenic organism) produces large amounts of the protein and it is collected, Protein (insulin) can be bottled and later injected into people who have a faulty gene for that trait
Transgenic organism
Any organism whose genome has been altered by the transfer of a gene or genes from another organism
Function of transgenic organisms
Genetic engineering can create new organisms, Introduced genes become a part of the transgenic organism’s DNA and are then passed on to subsequent generations, E.g- jelly fish have a fluorescent genre which can be removed and inserted into a single-celled mouse embryo
Production of factor VIII through rDNA
Identify and isolate the gene for factor VIII from a human liver cells using a restriction enzyme, Plasmid is removed from the bacterium and cut using the same restriction enzyme, Spliced plasmid and factor VIII gene join through ligase joining the sticky ends, Transgenic plasmid is placed into a mammalian cell and undergoes self-replication, Mammalian cell undergoes mitosis producing many plasmid containing cells capable of transcribing and translating the factor VIII gene in the plasmids, Large quantities of factor VIII are produced and is drained off, bottled and injected into haemophiliacs
Vaccine production using rDNA
Identify and isolate the gene for the attenuated antigen from a pathogen using a restriction enzyme, Use the same restriction enzyme to cut the plasmid that has been removed from bacterium, Spliced plasmid and antigen gene sticky ends are joined together through ligation, Transgenic plasmid is placed into yeast cell and undergoes self-replication, Yeast cell undergoes mitosis producing many plasmid containing cells capable of transcribing and translating the antigen gene in the plasmids, Large quantities of the attenuated antigen are produced through transcription and translation of the gene and is drained off, bottled and used to vaccinate people
Production of human growth hormone using rDNA
Identify and isolate the gene for HCG production from a human pituitary cell using a restriction enzyme, Use the same restriction enzyme to cut the plasmid that has been removed from bacterium, Spliced plasmid and HCG gene sticky ends are combined through ligation, Transgenic plasmid is replaced into bacterium and undergoes self-replication, Transgenic bacterium undergoes mitosis producing many transgenic bacteria capable of transcribing and translating the HCG gene , Large quantities of human growth hormone are produced through transcription and translation of the HCG gene which is then drained off, bottled and injected into people who are producing too little of their own hormone
