2.7 Genetic Control of Metabolism Flashcards
What are the three ways wild types of microorganisms can be improved?
Mutagenesis
Selective Breeding
Genetic Engineering
Describe ‘Selective Breeding’
Process by which only those cells with desired characteristics are breed
What is Mutagenesis?
The deliberate introduction of mutations by exposing the cells to mutagenic agents such as UV light and mustard agents
How can genetically new bacteria strains arise even though they reproduce asexually?
Horizontal Gene Transfer
Describe ‘Conjunction’ in relation to horizontal gene transfer
- Between two neighbouring cells
- Conjunction tube will form
- Plasmid will pass from one cell to another
- Both cells now have plasmids present
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
The quantity of a desired product can be increased by inserting what other genes?
- Genes that remove inhibitory controls
- Genes that amplify specific metabolic steps
What is a ‘transgenic’ organism?
A organism that carries a gene transferred from a different organism
Identify the three features of an effective plasmid vector
a) Restriction Sites
b) Marker Genes
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 ‘Marker gene’
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 are the two types of marker genes
Selectable
Screening
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
What is a ‘screening’ marker gene
A screening marker gene is a gene that changes the physical appearance of the cell
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
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
What type of marker gene would be required if the biologist wants to introduce antibiotic resistance into the cell culture which has uptaken the plasmid
Selectable
