2.7 genetic control of metabolism Flashcards
Wild strains
Microorganisms which exist in their natural form + environment - not tampered by humans.
Wild strains use
They are selected for use in industry for desirable genetic traits.
Or to undergo mutagenesis and recombinant DNA to improve traits
Mutagenesis
Where mutations are synthetically produced.
How are mutations increased
Mutagenic agents such as
Radiation
Mutagenic chemicals
Mutations features
Rare
Random and spontaneous
Detrimental
Use of mutagenesis
To provide organisms with advantageous and new alleles, through mutation, to be beneficial to humans.
Recombinant DNA technology
The transfer of gene sequences from one organism to another using vectors
Vectors def
A DNA molecule used to carry foreign genetic information into another cell.
Restriction endonuclease definition
The enzyme which is used to cut open vector at the restriction site and cut out specific genes from chromosomes in recombinant DNA
Restriction endonuclease features
The same restriction endonuclease must be used to cut both the plasmid and the gene, to ensure that the ends are complimentary to each other, these ends are called sticky ends.
Ligase use in recombinant DNA
To fuse together the desired gene and plasmid in recombinant DNA .
Process of genetic engineering/ recombinant DNA
A plasmid is removed from a bacteria/ yeast cell
The restricted site of plasmid is cut open using restriction endonuclease
Foreign gene is cut out of a chromosome by the same restriction endonuclease enzyme.
The foreign gene and plasmid are fused together by the ligase enzyme to produce a recombinant plasmid.
The recombinant plasmid is then inserted into a new bacterial/yeast host cell.
Criteria of effective vectors
Restriction sites
Regulatory sequences
Origin of replication
Selectable markers
Restriction sites definition
The site that contains target sequences of DNA where specific restriction endonuclease cuts, and foreign genes are inserted.
Purpose of restriction site
To be the location where foreign DNA is transferred into.
Regulatory sequence definition
The site which controls gene expression of the vectors genes and foreign genes.
Origin of replication
The site which allows for self replication without the foreign DNA being altered.
Selectable markers
A gene which protects a a vector or microorganism from selective agents such as antibiotics.
Use of vectors
Recombinant DNA
to prevent harmful microorganisms from surviving and causing harm to humans.
Why are artificial chromosomes more effective than plasmids
Artificial chromosomes and plasmids both contain the same features which make them effective vectors - however artificial chromosomes are larger and have a larger restriction site and therefore can carry more foreign DNA and larger genes from donor to host.
DNA of eukaryotes
Contains introns and exons
DNA of bacteria
Only contains exons
Why is yeast more effective than bacteria as a vector (referring to their plasmid )
Because polypeptides may become incorrectly folded if eukaryotic DNA is expressed in bacteria. (Prokaryotic)
