Genetic Control of Metabolism 2.7 Flashcards
How can wild strains of micro-organisms be improved?
Wild strains of micro-organisms can be improved by Mutagenesis.
What results in mutations, some of which may produce an improved strain of micro-organisms?
Exposure to UV light and other forms of radiation or mutagenic chemicals results in mutations, some of which may produce an improved strain of micro-organism.
What is another way of improving wild strains of micro-organisms?
Wild strains of micro-organisms can also be improved by Recombinant DNA
Technology, involving the use of Vectors.
What is a vector?
Vectors - these are DNA molecules used to carry
foreign genetic information into another cell.
What are the two types of vectors? Which one is preferable and why?
Vectors can be:
Recombinant Plasmids (Recombinant yeast cells may be used to produce active forms of the protein as plant or animal recombinant DNA expressed in bacteria may result in polypeptides being incorrectly folded.
Artificial Chromosomes
preferable as vectors when larger fragments of foreign
DNA are required to be inserted.
What is a restriction site on a vector?
Restriction Sites - contain target sequences of DNA where specific restriction
endonucleases cut.
What is a regulatory sequence on a vector?
Regulatory Sequences - control gene expression
What is the origin of replication on a vector?
Origin of Replication - allows self-replication
What is a selectable marker on a vector?
Selectable Markers - ensure that only micro-organisms that have taken up the vector grow in the presence of the selective agent (e.g. an antibiotic). Antibiotic
resistance genes protect the microorganism from a selective agent that would normally kill it or prevent it growing.
What is the function of restriction endonuclease?
Restriction Endonucleases cut open plasmids and specific genes out of chromosomes, leaving Sticky Ends.
When are complementary sticky ends produced?
Complementary sticky ends are produced when the same Restriction Endonuclease is used to cut open both the gene from the chromosome and the
vector.
What is the function of ligase?
Ligase seals the gene into the plasmid.
Why are genes that prevent the survival of the micro-organism in an external environment introduced?
As a safety mechanism, genes are often introduced that prevent the survival of the
micro-organism in an external environment.
