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BIOM 360 > Exam 3 Chapter 32 > Flashcards

Exam 3 Chapter 32 Flashcards

1
Q

Define symbiosis

A

an associateion of two or more different species of organisms

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2
Q

define ectosymbiont

A

organism located on surface of another organism (usually larger)

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3
Q

What is endosymbiont?

A

organism located within another organism

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4
Q

What is symbiont?

A

physical contact between dissimilar organisms of similar size

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5
Q

Define consortium

A

hosts that have more than one associated symbiont

relationships can be intermittent and cyclic or permanent

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6
Q

Define mutualism

A
  • some reciprical benefit to both partners
  • relationship with some degree of obligation (cannot live separately)
  • eg. insect host provides secure habitat and nutrients
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7
Q

What are two examples of Genomic Studies

A
  • B. aphidicola - some of smallest genomes known
    • extreme genomic stability
      • no duplication, translocation, inversion or horizontal tranfer
    • genes may be common among symbionts
    • eg. protozoan-Termite Relationship
      • termite provides food for protozoan, protozoan digests cellulose in wood particles, providing nutrients for termite
  • Zooxanthellae
    • Marine invertebrates harbor zooxanthellae
      • dinoflagellates harbored by marine invertebrates
      • provide organic carbon to host
    • Coral has pigments that protect algae form UV radiation
      • also provide N compounds, phosphates, and CO2
    • Coral bleaching: caused by temp increase
      • results form loss of photsynthetic pigments or expulsion of the zooxanthellae
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8
Q

Explaiin sulfide-baed mutualism

A

Tube worm-bacerial relationships

exist thousands of meters below ocean surface

chemolithotropic bacteria endosymbionts live within specialized organ (trophosome) of host ube worm

fix CO2 with electrons provided by H2O

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9
Q

Explain the rumen ecosystem

A
  • Ruminants
    • animals that have stomach divided into four compartments and chew a cud (cow, elk, buffalo)
    • In cows, acetate, Co2 and H2 are used by methanogenic archaea to generate methane (CH4), greenhouse gas (methane released by belching)
  • Rumen
    • upper part of the ruminant stomach
    • Contain large, diverse populations of microbes
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10
Q

Describe cooperation

A
  • Like commensalism, a positive (not obligate)symbiosis
  • benefits both organisms in relationship
  • Differs from mutualism because cooperative relationship is not obligatory
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11
Q

Explain commensalism

A
  • One organism benefits and the other is neither harmed nor helped
  • commensal; organism that benefits
  • often syntrophic
  • can also involve modification of environment by one organism, making it more suited for another organism
  • Ex:
    • nitrification (two different bacteria together)
    • spoilage of milk
    • formation of biofilm
    • skin or surface microbes on plants or animals
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12
Q

Explain predation, mode of killing

A
  • Attack usually killing prey
  • Mode of killing:
    • Bdellovibrio penetrates cell wall, grows outside plasma membrane
    • Vampirococcus epibiotic mode of attacking prey
    • Daptobacter penetrates prey then directly consumes the cytoplasmic contents
    • Myxococcus “wolf pack”
      • cells use gliding motility to creep, overtake their prey and release degradative enzymes
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13
Q

What are the benefits of predation

A
  • Microbial loop
    • organic matter produced by autotrophs is mineralized by microbial predators (ciliates) before reaching higher consumers
      • provides nutrients for primary producers
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14
Q

What is parasitism

A

one organism gains (parasite) and other is harmed (host)

  • always some co-existence
  • successful parasites have evolved to co-exist, offset one will die
  • example =
    • Typhus
      • Rickettsia typhi is causative agent
        • harbored in fleas, lives on rats
        • transmitted to humans by flea bites
    • Lichens
      • controlled parasitism
      • mycobiont - fungal partner
        • provides H2O, mnerals, shelter
      • phycobiont - alga or cyanobacterium
        • provides organic carbon and oxygen
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15
Q

What is the outcome of long-term parasitic relationship?

A

Genomic Reduction

  • parasite loses unused genomic information
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16
Q

What is Ammensalism

A

Negative impact of one organism on another based on release of a specific compound

ex: Antibiotic production by fungi and bacteria, use of antibiotic-producing streptomycin by ants to control fungal parasits, production of antibacterial peptides by insects and mammals

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17
Q

What is competition

A

occurs when two organisms try to aquire or use the same resource

two possible outcomes:

  • one organism dominates

Two organism share resource

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18
Q

What is superorganisms?

A
  • emerge when the gene-encoded metabolic processes of the host become integrated with those of the host
  • a blend of host and microbial trates where host and microbial cells co-metabolize various substrates, resulting in unique products
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19
Q

What is pathogenicity?

A

ability to produce pathological change or disease

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20
Q

What is pathogen?

A

any disease-producing microorganism

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21
Q

What is the Human Microbiome Project

A

Initiated 2007 by National institutes of Health (NIH)

attempt to define “normal” populations of microbes in and on human beings

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22
Q

Describe Normal microbiota of the human body

A

normal microbiota = microflora

relationship begins at birth

  • varies with environment and food source
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23
Q

Where is Bifidobacteria found? describe

A
  • Found in breast fed babies
  • Protrophic - can synthesize all amino acids and growth factors from simple carbohydrates
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24
Q

What are opportunistic pathogens?

A

members of normal microbiota that produce disease under certain circumstances

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25
Q

What is compromised host

A

debilitate host with lowered resistance to infection

26
Q

Explain the skin microbiota

A
  • both resistant and transient microbiota
  • mechanically strong barrier
  • Inhospitable environment
    • slighly acidic
    • high concentraiton of NaCL
    • many areas of low moisture
  • Inhibitory substances (eg. lysozyme, cathelicidins)
27
Q

Explain Acne Vulgaris

A
  • caused by activities of Propionibacterium acnes
    • sebum
      • fluid secrted by oil glands
    • Comedo
      • plug of sebum and keratin in duct of oil gland
28
Q

Explain nose and nasopharynx

A
  • Staphylococcus aureus and S. epidermidis
  • Nasopharynx may contain low numbers of potentially pathogenic microbes
    • S. pneumoniae, N. menigitidis and H. influenzae
29
Q

Explain the Oropharynx

A
  • Fivision of the pharynx laying between the soft palate and upper endge of epiglottis
    • alpha-hemolytic streptococci
    • diphtheroids
    • Gram negative cocci
    • anaerobes in tonsillar crypts
30
Q

Explain respritory tract

A

no normal microbiota

  • microbes moved by:

continuous stream of mucous with ciliated epithelial cells

phargocytic action

lysozyme in mucus

31
Q

Explain eye and external ear

A
  • Eye
    • from birth to life, small # of bacterial commensls are found on the confuctiva of eye
    • predominant = S. epidermidis
  • External ear
    • similar to skin flora as well as fungi
32
Q

Explain the mouth

A
  • Contains organism that survivve mechanical removal and adhearing to gums an dteeth
33
Q

Explain stomach

A

most microbes killed by acidic conditions

34
Q

Explaiin small intestine

A

Three divisions:

  1. duodenum (few organisms)
  2. Jejunum (picking up some)
  3. Ileum
    - flora present becomeing similar to that in colon (pH more alkaline)
35
Q

Explain large intestine (colon)

A
  • largest microbial population of body
    • replaced rapidly
    • most are anaerobes
    • Bacteroides thetaiontaomicron
      • colonizes exfoliated host cells, food particles and sloughed mucus
36
Q

Explain bacterium in genitourinary tract

A
  • Kidneys, ureter and bladder
    • normally free of microbes
  • distal portions of urethra
    • few microbes
  • femail genital track
    • flux due to menstral cycle
    • acid- tolerant lactobacilli predominant
37
Q

Define sterilization

A

destruction or removal of all viable organisms

38
Q

Define disinfection

A

Killing, inhibition, or removal of disease causing (pathogenic) organisms

disifectants:

agents, usually chemical, used for disinfection (usually used on inanimate objects)

39
Q

Define sanitization

A

reduction of microbial population to levels deemed safe (based on publich health standards)

40
Q

Define antisepsis

A

chemical agents that kill or inhibit growth of microorganisms when applied to tissue

41
Q

What are cidal agents?

A

kill (-cide suffice indicating ageint that cills)

germicide kills pathogens and many nonpathogens but not necessarily endospores

include bactericides, funicides, algicides, and viricides

42
Q

What are static agents

A

inhibit growth (-static suffix indicates growth inhibiting agent)

include bacteriostatic and fungistatic

43
Q

How does populations normally die? trend?

A

exponentially

44
Q

Explain the filtration method of removal

A
  • filtering liquids: membrane filters porous membranes with defined pore sizes that remove microorganisms for phsical screening
  • Filtering air: surgical masks, high efficiency particlate air (HEPA) filters
45
Q

Explain the Moist Heat method

A
  • Destroys viruses, fungi and bacteria
  • Boiling will not destroy spores and does not sterilize
  • degrades nucleic acids, denatures proteins and disrupts membanes
46
Q

Explain steam sterilization

A
  • carried out above 100 dec C which requires saturated steam under pressure
  • uses an autoclave
  • effective against all types of microorganisms (including spores!!!)
47
Q

Explain pasteurization

A
  • controlled heating at temperatures well below boiling
  • used for milk, beer, and other beverages
  • process does not sterilize but does kill pathogens present and slow spoilage by reducing the total load of organisms present
48
Q

What is dry heat methods for starilization

A
  • Dry heat incinerations: bench top incinerators are used to sterilize inoculated loops

Dry heat sterilization: less effective than moist heat sterilization, requireing higher temperatures and longer exposrue times

49
Q

Explain Ultraviolet (UV) radiation sterilization

A

wavelength of 260 is most bactericidal (DNA absorbs), prevents replication and transcription

50
Q

Explain ionizing radiation sterilization

A

Gamma radiation penetrates deep into objects. destroys bacterial endospores; not always effective against viruses

51
Q

Explain disinfection for control agen requirements

A

must be effective against wide variety of infectious agents at low concentrations

52
Q

Explain antisepsis for control agent requirements

A

overuse of antiseptics such as triclosan has selected for triclosan resistant bacteria and possibly antibiotic resistance

WHICHEVER CHEMICAL USED, IT MUST BE EFFECTIVE IN THE PRESENCE OF ORGANIC MATTER; SHOULD BE STABLE IN STORAGE

53
Q

Explain Phenolics

A
  • Commonly used as laboratory and hospital disinfectants
  • act by denatureing proteins and disruptin cell membranes
  • Ex: tuberculocidal, effective in presence of organic material and long lasting
  • Disagreeable odor and can cause skin irritation
54
Q

Explain alcohol use of sterilization

A
  • Among the most widely used disinfectants and antiseptics
  • two most common are ethanol and isopropanol
  • bactericidal, fungicidal, but not sporicidal
  • inactivate some viruses
  • Denatures proteins and possibly dissolve membrane lipids
55
Q

Explain Halogens

A
  • Any of five elements; fluorine, chlorine, bromine, iodine and astatine
  • important antimocrobial agent
56
Q

Explain iodine

A
  • Skin antiseptic
  • oxidizes cell constituents and iodinates proteins
  • at high concentraitons may kill spores
  • skin damage, staining, and allergies can be problem
  • iodophore
    • iodine complexed with organic carrier
    • released slowly to minimize skin burns
57
Q

Explain chlorine

A
  • Oxidizes cell constituents
  • important in disinfection of water supplies and swimming pools, used in dairy and food industries, effective household disinfectna
  • destroys vegetative bacteria and fungi
  • chlorine gas is sporicida
  • can react with organic matter to form carcinogenic compounds
58
Q

Explain heavy metals

A
  • eg. ions of mercury, silver, arsenic, zinc and copper
  • effective but usually toxic
  • combine with an inactivate proteins; may aslo percipitate proteins
59
Q

Explain quaternary ammonium compounds

A
  • detergents that have antimicrobial activity and are effective disinfectants
    • amphipathic organic cleansing agents
60
Q

Explain Aldehydes

A
  • COmmonly used agents are formaldehyde and glutaraldehyde
  • sporicidal and can be used as chemical sterilants
  • combine with and inactivate nucleic acids and proteins
61
Q

Explain sterilizing gasses

A
  • Used to sterilize heat-sensitive materials
  • microbicidal and sporicidal
  • Ethylene oxide sterilization; is carried otu in equipment resembling an autoclave
  • Betapropiolactone and vaporized hydrogen peroxide
  • combind with an inactive DNA and Protiens
62
Q
A

BIOM 360 (7 decks)

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