Why can one type organism express the gene of another
Because all species use the same genetic code
How do scientist take advantage of the fact that a lll species share the same genetic code
by coaxing cells to take up Recombinant Dna
RECOMBINANT DNA
genetic material that has been spliced together from multiple organisms.
this is referred to as genetic engineering/ or genetically modified
TRANSGENIC ORGANISM
one that receives recombinant DNA
The 4 steps in creating a transgenic organism
- Acquire source Dna
- Select a cloning vector
- Create recombinant dna
- Insert the recombinant Dna into a recipient cell
- ACQUIRE SOURCE DNA
- from a source cell ( bacteria, animal or Plant
Why is it problematic if the source is a eukaryotic cell and the recipient is a prokaryote
Bacterial cells cannot remove introns from mRNA, so the DNA would encode a defective protein
How is a DNA copy made from a copy of mRNA (REVERSE TRANSCRIPTION)
- a mature mRNA molecule with its intron already removed, is isolated.
- An enzyme called REVERSE TRANSCRIPTASE is used to create DNA copy of the mRNA.
What is the importance of REVERSE TRANSCRIPTION in transgenic organism creation
When transferring a Eukaryotic cell to a bacteria : Bacterial cells cannot remove introns from mRNA, so the DNA would encode a defective protein. an mRNA with introns already removed is used to create DNA. this Dna ( cDNA) is now able to encode the eukaryotic protein within the bacteria
- CLONING VECTOR
a self-replicating genetic structure that will carry the source DNA into the recipient cell
An example of a common CLONING VECTOR
- PLASMIDS
2. Viruses ( they are modified so they can transport DNA but not a disease)
PLASMID
are small circle of DNA separate from the cell’s chromosome.
- CREATE RECOMBINANT DNA
CREATE RECOMBINANT PLASMIDS
- DNA fragments that can be spliced together are created by using RESTRICTION ENZYMES to cut DNA at specific bases
- selected fragments are spliced together ( recombinant DNA) and are used to attach to plasmids
RESTRICTION ENZYMES
what are their natural function
are proteins that cut double stranded DNA at a specific base sequence.
Their natural function is to protect bacteria by cutting up DNA from infecting viruses.
- INSERT THE RECOMBINANT DNA INTO A RECIPIENT CELL
- bacteria cell wall is zapped with electricity creating a temporary hole that admits the DNA.
or//
“Gene guns” shoot DNA-coated pellets directly into the cells.
or//
packaged into liposomes that fuses withe the recipient ‘s membrane
or//
hitched to a virus that “infects’ the cell
How is a transgenic animal crated since it is incapable of growing from an isolated cell ( like a plant)
by using viruses to introduce genes into fertilized egg. the organism that develops will carry the foreign genes in every cell.
. What is recombinant DNA
Recombinant DNA is the combined DNA from 2 or more organism
What are transgenic organisms, and how are they useful?
Transgenic organisms are organisms that contain recombinant DNA. They produce drugs and other useful chemicals, degrade pollutants, incorporate pesticides in their tissues, are models for medical research, and secrete human proteins.
What are the steps in creating a recombinant plasmid?
The steps in creating a recombinant plasmid include:
- using restriction enzymes to cut out the gene sequence from donor DNA;
- cutting the plasmid with the same restriction enzymes;
- allowing the donor sequence to combine with the plasmid DNA.
. How do bacteria, plant, and animal cells take up recombinant DNA
Bacteria, plant, and animal cells are sometimes induced to take up recombinant DNA by exposure to electricity. Scientists also make cells take up new DNA by shooting it into cells with gene guns, inserting it into liposomes, and inserting it as plasmids into bacteria that enter plant cells and inject the plasmids.
