Biomedical Core

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Biomedical Core
2012-12-10 21:45:41

Objective 10.11
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  1. Bacteria can exchange genetic material through three defferent mechanisms. What are they?


  2. Bacteria have the ability to exchange genes and undergo
    Genetic Recombination.
  3. This exhange of genetic material contribute to the ability of some bacteria to acquire
    antibiotic resistance
  4. During transduction
    an asexual genetic process, viruses called bacteriophages or simply phages transfer genes between mating bacteria.
  5. The process of transduction uses a bacteriophage to insert the resistant DNA into the
  6. When a bacterium dies, fragments of its DNA are taken up by
    neighboring bacteria
  7. In transformation
    DNA is acquired directly from the environment. (This DNA was released from another cell, through lysis or some other disruption.
  8. These naked DNA fragments are taken up by the recipient cell through the action of ______ ________ found on the _______ _________.  The fragments are then ________ into the ________ cell's DNA by ________ ________.
    carrier proteins; cell membrane; "spliced"; enzymatic action
  9. Conjugation requires
    cell-to-cell contact for DNA to be transferred from a donor cell to a recipient cell.
  10. It is at the _______ that DNA is transferred from one cell to another, usually in much larger quantities than the other two mechanisms.
    F-pilus (sex pilus)
  11. Plasmids are
    extrachromosomal pieces of DNA in the cytoplasm of some bacteria.
  12. Conjugation utilizes a
  13. Bacteria often develop their drug resistance through plasmids, also called
    resistance transfer factors
  14. Conjugation transfers a greater amount of DNA than
    transformation or transduction
  15. Genetic recombination by the three processes described above transfers
    DNA leading to new strains of bacterium including antibiotic resistant strains
  16. Antimicrobial agents include
    substances used to specifically treat infectious microbial diseases.
  17. Antibiotics are
    antimicrobial agents containing substances derived from other organisms.
  18. Spectrum of Activity.  Antimicrobials can be either
    Broad spectrum or Narrow spectrum drugs.
  19. Broad Spectrum affect
    a wide range of microorganisms including gram positive and gram negative bacteria.
  20. Narrow Spectrum affect
    a limited number of microorganisms or a single taxonomic group.
  21. Bacteriostatic
    Inhibits organism growth.
  22. Bacteriocidal
    Kills the organism.
  23. There are numerous antimicrobials and antibiotics: some affect the _____ _____; other disrupt the ____ _______.  Other groups alter _______ ________ and genetic activity.  The spectrum of activity of antibiotics varies among the ______ of antibiotics.
    cell wall (penicillin); cell membrane; protein synthesis; types
  24. Resistance to antibiotics increases each
  25. Resistance of microorganisms to antibiotics occurs through:
    • Overuse of antibiotics.
    • Plasmids
    • Genetic transfer mechanisms.
    • Development of neutralizing enzymes.
    • Alteration of pathways used by antibiotic.
    • Altering cell membrane permeability.
  26. What is used for the antimicrobial susceptibility testing?
    Agar Disc Diffusion
  27. Agar Disc Diffusion
    Uses paper discs impregnated with a specific concentration of the antimicrobial to be tested.
  28. Zones of inhibition around the disc are measured and compared to those for control organisms with know zone sizes.  Results are reported as
    sensitive, intermediate, or resistant.