Exam 3 Chapter 32 Flashcards
(62 cards)
1
Q
Define symbiosis
A
an associateion of two or more different species of organisms
2
Q
define ectosymbiont
A
organism located on surface of another organism (usually larger)
3
Q
What is endosymbiont?
A
organism located within another organism
4
Q
What is symbiont?
A
physical contact between dissimilar organisms of similar size
5
Q
Define consortium
A
hosts that have more than one associated symbiont
relationships can be intermittent and cyclic or permanent
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
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
- extreme genomic stability
- 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
- Marine invertebrates harbor zooxanthellae
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
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
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
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
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
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
- organic matter produced by autotrophs is mineralized by microbial predators (ciliates) before reaching higher consumers
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
- Rickettsia typhi is causative agent
- Lichens
- controlled parasitism
- mycobiont - fungal partner
- provides H2O, mnerals, shelter
- phycobiont - alga or cyanobacterium
- provides organic carbon and oxygen
- Typhus
15
Q
What is the outcome of long-term parasitic relationship?
A
Genomic Reduction
- parasite loses unused genomic information
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
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
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
19
Q
What is pathogenicity?
A
ability to produce pathological change or disease
20
Q
What is pathogen?
A
any disease-producing microorganism
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
22
Q
Describe Normal microbiota of the human body
A
normal microbiota = microflora
relationship begins at birth
- varies with environment and food source
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
24
Q
What are opportunistic pathogens?
A
members of normal microbiota that produce disease under certain circumstances
25
What is compromised host
debilitate host with lowered resistance to infection
26
Explain the skin microbiota
* 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
Explain Acne Vulgaris
* caused by activities of Propionibacterium acnes
* sebum
* fluid secrted by oil glands
* Comedo
* plug of sebum and keratin in duct of oil gland
28
Explain nose and nasopharynx
* Staphylococcus aureus and S. epidermidis
* Nasopharynx may contain low numbers of potentially pathogenic microbes
* S. pneumoniae, N. menigitidis and H. influenzae
29
Explain the Oropharynx
* 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
Explain respritory tract
no normal microbiota
- microbes moved by:
continuous stream of mucous with ciliated epithelial cells
phargocytic action
lysozyme in mucus
31
Explain eye and external ear
* 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
Explain the mouth
* Contains organism that survivve mechanical removal and adhearing to gums an dteeth
33
Explain stomach
most microbes killed by acidic conditions
34
Explaiin small intestine
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
Explain large intestine (colon)
* largest microbial population of body
* replaced rapidly
* most are anaerobes
* Bacteroides thetaiontaomicron
* colonizes exfoliated host cells, food particles and sloughed mucus
36
Explain bacterium in genitourinary tract
* 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
Define sterilization
destruction or removal of all viable organisms
38
Define disinfection
Killing, inhibition, or removal of disease causing (pathogenic) organisms
disifectants:
agents, usually chemical, used for disinfection (usually used on inanimate objects)
39
Define sanitization
reduction of microbial population to levels deemed safe (based on publich health standards)
40
Define antisepsis
chemical agents that kill or inhibit growth of microorganisms when applied to tissue
41
What are cidal agents?
kill (-cide suffice indicating ageint that cills)
germicide kills pathogens and many nonpathogens but not necessarily endospores
include bactericides, funicides, algicides, and viricides
42
What are static agents
inhibit growth (-static suffix indicates growth inhibiting agent)
include bacteriostatic and fungistatic
43
How does populations normally die? trend?
exponentially
44
Explain the filtration method of removal
* 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
Explain the Moist Heat method
* Destroys viruses, fungi and bacteria
* Boiling will not destroy spores and does not sterilize
* degrades nucleic acids, denatures proteins and disrupts membanes
46
Explain steam sterilization
* carried out above 100 dec C which requires saturated steam under pressure
* uses an autoclave
* effective against all types of microorganisms (including spores!!!)
47
Explain pasteurization
* 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
What is dry heat methods for starilization
* 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
Explain Ultraviolet (UV) radiation sterilization
wavelength of 260 is most bactericidal (DNA absorbs), prevents replication and transcription
50
Explain ionizing radiation sterilization
Gamma radiation penetrates deep into objects. destroys bacterial endospores; not always effective against viruses
51
Explain disinfection for control agen requirements
must be effective against wide variety of infectious agents at low concentrations
52
Explain antisepsis for control agent requirements
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
Explain Phenolics
* 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
Explain alcohol use of sterilization
* 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
Explain Halogens
* Any of five elements; fluorine, chlorine, bromine, iodine and astatine
* important antimocrobial agent
56
Explain iodine
* 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
Explain chlorine
* _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
Explain heavy metals
* eg. ions of mercury, silver, arsenic, zinc and copper
* _effective but usually toxic_
* combine with an _inactivate proteins_; may aslo percipitate proteins
59
Explain quaternary ammonium compounds
* detergents that have antimicrobial activity and are effective disinfectants
* amphipathic organic cleansing agents
60
Explain Aldehydes
* COmmonly used agents are formaldehyde and glutaraldehyde
* _sporicidal_ and can be used as chemical sterilants
* combine with and _inactivate nucleic acids and proteins_
61
Explain sterilizing gasses
* 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_
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