genetic control of metabolism

• what can wild strains of micro organisms be improved by?

  mutagenisis or recombinant DNA technology
• what can result in mutations

  exposure to UV light, other forms of radiation or mutagenic chemicals
• some mutations can produce...?

  an improved strain of micro organism
• what does recombinant DNA technology involve

  the use of recombinant plasmids and artificial chromosomes as vectors
• what is a vector

  a DNA molecule used to carry genetic information to another cell
• when are artificial chromosomes preferable to plasmids


  when larger fragments of foreign DNA are required to be inserted
• what do restriction endonucleases do

  cut open plasmids and specific genes out of chromosomes leaving sticky ends
• when are complimentary sticky ends produced

  when the same restriction endonuclease is used to cut open the plasmid and the gene from the chromosome
• what is the role of ligase

  seals the gene into plasmid
• 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 endonucleases cut
• what do regulatory sequences control

  gene expression
• what does origin of replication allow

  self replication of the plasmid/artificial chromosome
• what do selectable markers such as antibiotic resistance genes protect


  the micro organism from a selective agent (antibiotic) that would normally kill or prevent it from 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 can expression of plant or animal genes in bacteria result in

  polypeptides that are folded incorrectly
• why may recombinant yeast cells be used as plant/animal genes

  because eukaryotic proteins may be produced more successfully in a recombinant yeast cell