2.7 Genetic Control of Metabolism Flashcards
Describe what a wild strain of a micro-organism is?
It is the phenotype of the typical form of a species of micro-organism as it occurs in nature.
What are the two ways wild types of microorganisms can be improved?
Mutagenesis
Recombinant DNA technology
What is Mutagenesis?
the creation of mutations through the use of mutagenic agents in the effort of producing an improved strain of micro-organism.
How can genetically new bacteria strains arise even though they reproduce asexually?
Horizontal Gene Transfer
Describe ‘Transformation’ in relation to horizontal gene transfer
Transformation is when the bacterial cell takes up foreign DNA from it surrondings
How can new genotypes of fungi be produced?
Reproducing sexually - mixing together different existing strains
Describe the process of ‘Recombinant DNA technology’
Processing of transferring a desirable gene from one species to another
Describe the function of ‘Restriction Endonuclease’
Degradation enzymes that cuts open the plasmid and cuts the desired gene out of the genome of the other organism
Describe the process of genetic engineering
- Restriction Endonuclease cuts the plasmid open
- Same RE cuts out the desired gene
- The gene is inserted into plasmid and ‘glued in’ by the Ligase
- The plasmid is taken up into the bacterium
Describe the function of ‘Ligase’
Ligase glues the sticky ends together, sealing the gene into the plasmid
Why must the same restriction enzyme be used to cut both the plasmid and the desired gene?
To ensure the sticky ends are complementary and the base pairs match up
Identify the three features of an effective plasmid vector
a) Restriction Sites
b) Selectable Markers
c) Origin of Self Replication
What is the ‘Origin of Self Replication’
Region of the plasmid that contains the genes from self replication
What is a ‘Selectable Markers’
A marker gene is a gene that acts as a recognisable tag for a cell that has taken up the transferred plasmid
What is the ‘Restriction Site’ of a plasmid
A specific DNA sequence that can be cut open using the restriction endonuclease
What is a ‘selectable’ marker gene
A selectable marker gene is a gene that will protect the organism from something that would normally kill it eg. antibodies
Why would you use recombinant DNA technology with yeast cells rather than bacterial cells?
Due to the fact that a yeast cell is eukaryotic, it has the facilities for post translational modification and protein folding
Why would a selectable marker be used?
It will only be present in the genetically modified organisms so can be used to kill or prevent growth of non-genetically modified organisms. Ensuring that only the micro-organisms that have taken up the vector grow.
Describe a safety precaution to prevent survival of recombinant microbe outside lab
Introduction of genes that prevent survival outside of culture
Example: gene that forces reliance on a chemical only found in culture medium
