unit 2 KA7 - genetic control of metabolism Flashcards
how can wild strains of bacteria be improved
by mutagenesis, or recombinant DNA technology
what can result in mutations, some of which may product an improved strain of micro-organism?
exposure to UV light and other forms of radiation or mutagenic chemicals
what does recombinant DNA technology involve the use of
recombinant plasmids and artificial chromosomes as vectors
what is a vector
a vector is a DNA molecule used to carry foreign genetic information into another cell
what are used as vectors during recombinant DNA technology
artificial chromosomes
when are artificial chromosomes preferable to plasmids as vectors?
when larger fragments of DNA are required to be inserted
what is the role of restriction endonucleases in recombinant DNA technology
they cut open plasmids and specific genes out of the chromosomes, leaving sticky ends
what is the role of ligase in recombinant DNA technology
it seals the gene into the plasmid
when are complementary sticky ends produced
when the same restriction endonuclease is used to cut open the plasmid and the gene from the chromosome
what do recombinant plasmids and artificial chromosomes contain?
restriction sites, regulatory sequences, an origin of replication and selectable markers
what do restriction sites contain
target sequences of DNA where specific restriction endonuclease cut
what do regulatory sequences control
gene expression
what does origin of replication allow
self replication of the plasmid/aritifical chromosome
what are examples of selectable markers
anti-biotic resistant genes
what do selectable markers protect
they protect the micro-organism from a selective agent (antibiotic) that would normally kill it or prevent it growing
what do selectable marker genes present in the vector ensure
that only micro-organisms that have taken up the vector grow in the presence of the selective agent (antibiotic)
what is a safety mechanism for genetic control of metabolism
genes that prevent the survival of the micro-organism in an external environment
why are recombinant yeast cells used to produce active forms of the protein which are inactive in bacteria
because plant or animal recombinant DNA expressed in bacteria may result in polypeptides being incorrectly folded
what is mutagenesis
the creation of mutations
how can the rate of mutagenesis be increased
by exposing organisms to mutagenic agents eg UV light, radiation or mutagenic chemicals
