Biomed Module 6 obj.4-7

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Biomed Module 6 obj.4-7
2012-11-03 05:15:35
Biomed Module obj

Biomed Module 6 obj.4-7
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  1. Culter media can be either ________ or________________ forms whi h contain agar.
    liquid, semi-solid
  2. Agar
    a neutral gel-like substance derived from seaweed.
  3. When mixed wtih nutrients , bacteria grow to from dense masses called ___________.
  4. Enriched Media
    • Contains substances that bacteria love that encourage the growth of most bacteria.
    • Used as a general overview of what's growing in the culture
    • Examples are sheeps blood agar(SBA) and chocolate agar.
  5. Selevtive Media
    • Contains inhibitors that allow certain types of bacteria to grow and form colonies while inhibiting others.
    • For example, certain selective agars like MacConkey agar allow only the growth of gram negative organisms.
  6. Differential Media
    • Roughly groups vacteria based on fermentation of carbohydrates.
    • An example is MacConkey agar which contains sugar lactose.
    • Bacteria that ferment lactose turn red, those that dont are colorless.
  7. True or False : When culturieng bacteria, it is important to remember that bacteria may require special atmonpheric conditions in their enviornment.
  8. Aerobes require :
    • atmospheric oxygen, often enhanced with additonal carbon dioxide.
    • Special incubators provide the right trmperature and gas levels for aerobes to grow.
    • Examples are Steptococcus, Staphylococcus and E. coli
  9. Anaerobic organisms require
    • special conditions that remove atmospheric oxygen.
    • Special anaerobic chambers or jars that remove atmospheric oxygen may be used for culture.
    • Example: Clostridium species that cause disorders such as gangrene, botulism and tetanus.
  10. Microaerophilic organisms grow best ...
    • in an environment of reduced oxygen and increased CO2.
    • These may be grown in jars in which a candle is lit before the jar is sealed.
    • The burning candle uses the oxygen in the jar and adds carbon dioxide.
    • Example: Camplycacter- which causes intestinal disorders.
  11. The process most bacteria grow and divide is call _______, also known as ______.
    Binary fission, Transverse fision
  12. True or False: Under favorable nutritional and enviornmental conditions bacterial cells will double their individual size.
    • True.
    • The parent cell is also duplicating its internal contents
    • Through binary fission, the parent divides into two identical cells
    • This process of growth and divison continues as long as favorable enviornmental and adequate nutritional conditions exist
  13. How do bacteria cells replicate differnt ly then other cells?
    • Bacterial cells do not have a cell cycle
    • They are continuously dividing and replicating their DNA
  14. What are the phases of cell division?
    • Lag phase
    • Log phase
    • Stationalry phase
    • The Decline (Death) phase
  15. Lag Phase
    • Bacterial are metavboically active-synthesizing enzymes and producing energy as ATP
    • They are also increasing in size
    • they do not reproduce in significant numbers during this pahse
  16. Log Phase
    • The period of rapid expinential growth
    • Generation Time- the genetically determined period of logarithmic growth which varies by bacterial species from minutes to hours.
    • Most are under 10 hours
    • Log growth will continue as long as there are sufficient nutrients and enviornment have suitable conditions available for the sinthesis of ATP
  17. Stationary Phase
    • the leveling off period
    • phse of bacterial growth in which the non-replicating cells are about the same in number as thos still reproducing new cells
  18. Decline (Death) phase
    the number of cells dying is greater than the number of new cells arising from divison
  19. What does symbiosis mean?
    "Living together" 
  20. List three different symbiotic relationships with a liveing host
    • Mutualism
    • Parasitism
    • Commensalism
  21. Mutualism
    • both members of the association benefit
    • Classic example: Escherichia coli (E. coli)- Living in the large intestine of humans
    • -the bacterial love the warm environment humans provide 
    • -Humans benefit from the vitamine K that E. coli produces
  22. why is vitamin K essential ?
    It aids in the blood clotting process
  23. Parasitism
    • In which one organism, the parasite, benefits from the relationship and the other organism, the host, is harmed
    • There are many types of parasites
    • Two examples: Malaria and tape worms
  24. Comensalism
    • One oraganism benefits and the other is neutral
    • Example: the bacteria that live on our skin
    • They benefit frim the nice warm enviornment, the human host is not harmed.
  25. The vast majority of microbes that make up our indigenous flora are _______, living on and within humans without causing disease.
  26. Before birth, the human fetus remains in a sterile environment unless organisms such as the _____ _____ (Rubella) penetrate the placenta and infect the fetus.
    Measles virus
  27. _______ and _______, if carried by the mother, pose an infection threat to infants.
    Herpes virus, HIV
  28. Newborns at birth are relatively free of _________ and must aquire them from interaction with their __________.
    microorganisms, enviornments
  29. Newborns at birth are relatively free of _________ and must aquire them from interaction with their __________.
    • microorganism, environments
    • These organism overtime become a part of their human microflroa
  30. Why are infents so suseptable to pathogens during birth?
    • Infants soft moist skin is an ideal enviornment 
    • examples: Group B streptococcus-causes sevire life threatening infectionsin new borns, Candida
  31. As adults, indigenous flora exist either as _____or ______ microflora, using the secretions of the host as nutritional sources.
    resident, transient
  32. Resident and transient microflora are usally found:
    • The skin and hair (staphylococci, Bacillus species and others)
    • Conjuctiva (usually match those found on the skin)
    • Mouth, nose, and throat (staphylococci, streptococci, yeast, Neisseria species, among others)
    • Passagways of the intestinal, reproductive and intstinal tracts, 
    • Most of our indigenous microorganisms reside in the lower digestive tract
  33. Transient Flora
    • come and go organism that exist in the same areas occupied by resident flora
    • Can be aquired alomos everywhere
    • may persist for hours, months, years
    • My become opportunist and cause infections in hosts whose protective mechanism have been compromised 
  34. Normal Flora
    Organism that live on or in the body but do not usually cause disease
  35. Normal flora in infants
    • At birth infants have not acquired their normal fora
    • Infants have less organic acid available to minimize bacterial growth.
    • their soft moist skin is an ideal envieronment for pathogens to grow.