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Microbiology > Chapter 11 > Flashcards

Chapter 11 Flashcards

1
Q

5 characteritics of phylogeny of eukarya

A
  • sequencing of 18S rRNA genes is used to infer the phylogeny of eukaryotes
  • relationship between 18S rRNa genes is weaker for eukaryotes than 16S rRNA is for prokaryotes
  • phylogenies have been construct by taking into account other genes (tubulin, RNA polymerase and ATPase) - MLST
  • new insight have arisen because of these new phylogenies (fungi and animals are closely related and they are closed to amoebozoa)
  • eukaryotic molecular phylogeny is still being refined
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2
Q

6 characteristics of green algae

A
  • also called chlorophytes
  • closely related to plants
  • most green algae inhabit freshwater, but some are marine or territorial
  • can be unicellular (usually flagellated) to multicellular
  • have sexual and asexual reproduction
  • endolithic algae grow inside porous rocks
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3
Q

5 characteristics of red algae

A
  • also called rhodophytes
  • mostly marine, but some freshwater and terrestrial
  • red color is from phycoerythrin, an accessory pigment. At greater depth, more phycoerythrin is produced by cells
  • most species are multicellular, some are unicellular
  • unicellular: galdieria, lives in acidic hot springs
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4
Q

3examples of red algae and 3 of green algae

A 
red:
- dinoflagellate
- apicomplexans
- stramenopiles
green:
- euglenids
- chlorarachniophyte
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5
Q

4 common characteritics of diplomonads and parabasalids

A

unicellular
flagellated
lacks chloroplast
live in anoxic habitats

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6
Q

3 characteristics of diplomonads

A
  • have 2 nuclei of equal size
  • have mitosomes (degenerated mitochondria)
  • key genera: Giardia (cause giardiasis)
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7
Q

4 characteristics of parabasalids

A
  • contain a parabasal body (structural support to the golgi complex)
  • lack mitochondria, but have hydrogenosomes for anaerobic metabolism
  • live in intestinal and urogenital tracts of animals as parasites or symbionts
  • key genera: trichomonas
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8
Q

what is amitochondriate eukaryotes + 2 things they have instead

A
  • lack a mitochondria. At first, they looked like very primitive eukaryotes
    instead, they have:
    1. mitosome (ex: diplomonads): reduced form of mitochondrion- derived from mitochondrion- that does not have enzymes of TCA cycle and not have a respiratory chain. They are involved in the maturation of iron-sulfur clusters
  1. hydrogenosomes (ex: parabasalids): present in eukaryotes whose metabolism is striclty fermentative. It carries out the oxidation of pyruvate to H2, O2 and acetate. sometimes H2-consuming endosymbiotic archaea are also present (methanogens) - primary endosymbiosis
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9
Q

5 characteristics of cysts

A
  • some species of protistes are able to differenciated, becoming encysted
  • cysts are similar to the endospores produced by prokaryotes
  • protect the cells against deleterious environmental conditions
  • survive long periods of stravation/dessication
  • survive infection by prokaryotes
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10
Q

an example of diplomonads that infect food + 4 steps

A

giardia lamblia

  1. cyst (infective stage)
  2. contamination of water, food or hands/fomites with infective cysts
  3. ingestion in human body (giardiasis)
  4. go out in stool (caca)
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11
Q

2 characteristics of tichomonas vaginalis

A

STI in humans: most common parasites infection in developped countries
- does not form cysts, does not survive well outside host (adapted to sexual transmission)

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12
Q

what are euglenozoans + 3 characteristics of one of its species: kinetoplastid

A

euglenozoans: unicellular flafellated eukaryotes
kinetoplastids:
1. named for the presence of the kinetoplast, a mass of circular DNA present in their single, large mitochondrion
2. live primarly in aquatic habitats feeding on bacteria
3. some species cause serious diseases in human

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13
Q

4 characteristics of trypanosoma brucei (a kinetoplastid)

A
  • causes African sleepong sickness, a chronic and usually fatal infection
  • lives and grow in the bloodstream, infects the central nervous system during the later stage
  • transmitted by the tsetse fly
  • the single flagellum is enclosed in a membrane flap
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14
Q

3 characteristics of euglenids (ex: euglena)

A
  • nonpathogenic and phototrophic
  • contain chloroplast, can exist as heterotroph; will lose its chloroplasts if incubated in the dark for a long time
  • can feed on bacteria by phagocytosis
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15
Q

5 characteristics of caulobacter

A
  • asymmetric division each cell cycle
  • stalked mother cell produces morphologically distinct progeny:
    1. daughter swarm cell (can’t reproduce at first)
    2. daughter non-motile stalk cell
  • mother cells porduce one set of offspring per cell cycle
  • if conditions are favorable stalked daughter can undergo another cycle of DNA replication and cell division
  • swarmer must undergo an obligate period of growth and differenciation before beginning cycle anew
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16
Q

1 characteristique of alveolate + 3 members

A
  • characterized by the presence of alveoli, which are sacs underneath the cytoplasmic membrane:
  • may function to help cells maintin osmotic pressure
  • in paramecium: contractile vacuole
  • members are ciliates, dinoflagellates,apicomplexans
17
Q

6 characteristics of ciliates (role of cilia, its composition)

A
  • ciliates possede cilia at some stage of their life
  • most widely distributed genera is paramecium
  • use cilia to obtain food and for motility
  • ciliates have 2 nuclei (macronucleus and micronucleus)
  • during conjugation (sexual reproduction) two paramecia exchange micronuclei
  • some ciliates are animal parasites, some are animal symbionts (in the rumen)
18
Q

3 characteristics of dinoflagellates (alevolate)

A
  • diverse marine and freshwater phototrophic organisms
  • some are free-living and others live symbiotically with corals
  • have 2 flagella with different insertion points on the cell: transverse and longitudinal flagellum
19
Q

4 characteristics toxicity of dinoflagellates

A
  • some species secrete neurotoxins
  • in warm and polluted water, dinoflagellates can reach very high numbers
  • dense suspension of the cells are called red tides
  • associated with human poisoning (paralytic shellfish poisoning). Accumulation of toxic dinoflagellates in mussels
20
Q

4 characteristics of apicomplexans (alveolates)

A
  • obligate parasites of animals (ex: carry by cat)
  • complex life cycle:
    sporozoite (transmission)
    gametocyte (sexual reporduction)
    other stages
  • contain apicoplasts, degenerate chloroplasts that lack pigments and phototrophic capacity, but still carry many anabolic pathway
  • causes severe disease such as malaria (plasmodium), toxoplasmosis (toxoplasma), coccidiosis (eimeria)
21
Q

2 characteristics of stramenopiles + 4 members

A
  • all have flagella with many short hairlike extensions
  • chemoheterotrophs and phototrophic members
  • 4 members: diatomas, oomycetes, golden algae and brown algae
22
Q

4 characteristics oomycetes (chemoheterotroph)

A
  • also called water mold- filamentous growth
  • presence of coneocytic hyphae (multinucleate)
  • cell walls are made of cellulose, not chitin as in fungi
  • phytophtora infestans: late blight disease in potatoes and contributed to the Irish potato famine
23
Q

4 characteristics of gloden algae (phototroph)

A
  • also called chrysophytes
  • most are unicellular, some are colonial (form groups)
  • they are named for their golden-brown color
  • choroplasts pigments dominated by the carotenoid fucoxanthin
24
Q

5 characteristics of diatoms

A
  • unicellula, phototrophic
  • over 100,000 species of diatoms
  • freshwater and marine habitats
  • frustules: cell walls made of silica with proteins and polysaccharides attached to it. protect against predation
  • appeared on earth about 200 millions years ago
25
Q

what distinguish cercozoans and radiolarians from other protistes

A

by their threadlike pseudopodia (pseudo= false, podia= feet) ** thin long finger

26
Q

3 characteristics of foraminifera (cercozoans)

A
  • exclusively marine organisms
  • they from ornate shell-like structures called tests
  • tests are made from organic materials reinforced with calcium carbonate
27
Q

3 characteristics of radiolarians

A
  • mostly marine, heterotrophic organisms
  • tests are made of silica
  • name is derived from radial symmetry of tests
28
Q

one characteristics of amoebozoa + 3 members

A
  • terrestrial and aquatic protistes that used pseudopodia for movement and feeding (phagocytosis of bacteria and smaller protists). Move by amoeboid movement (cytoplasmic streaming)
    3 major classes:
    1. gymnamoeba: free-living, inhabit soil and aquatic environment
    2. entamoebas: parasites of vertebrate and inverterbrate (ex: entamoeba hystolytica)
    3. slime molds (microscopic slugs): previously grouped with fungi because they have similar life cycle: produce fruiting bodies with spore for dispersal, motile (can move across surface rapidly)
29
Q

plasmodial slime molds life cycle (3)

A
  • have vegetative forms that are masses of protoplasm (organelles, cytoplasm, nucleus) of indefinite size and shape (plasmodium), that contain mulitple nuclei
  • from a plasmodium, a sporangium can form, containing multiple haploid spores (dormant, resistant, for dispersal)
  • the spores germinates, yielding a swarmer cell (flagellated or amoeboid). The fusion of 2 swarmer cells regenerates the diploid plasmodium
30
Q

4 characteristics of amoebozoa - cellular slime mold

A
  • cellular slime molds: vegetative forms composed of single amoebae (haploid)
  • aggregate of separate amoeboid cells form a pseudoplasmodium (slug) that can move as single unit (cells do not fuse)
  • fruiting body is formed, cells differentiate into spores
  • under certain conditions: may form diploid macrocysts that undergo meiosis to form new amoebae (haploid): sexual reproduction
31
Q

4 characteristics of fungi

A
  • most cell wall made of chitin
  • most are multicellular, forming a network of hyphae (mycelium).
    1. coenocytic: cytoplasm and nuclei are not subdivided into cells
    2. septate: nuclei are separated by cross wall
  • hyphae that extend above the surface can produce asexual spores called conidia. Conidia are often pigmented and resistant to drying.
  • feed by secreting extracellular enzymes that digest complex organic materials (polymers). monomers, or short polymers are then assimilated
32
Q

symbioses and pathogenosis of fungi

A
  • fungi can cause disease in plants and animals
  • many fungal plant pathogens form specialized hyphae- haustoria- to penetrate the plant cells and consume the cytoplasm
  • mycoses in human range in severity from athlete foot to histoplasmosis (systemic infection). Immunosuppression is a major risk factor
33
Q

2 characteristics of fungal reproduction

A
  • most fungi reproduces by asexual means (3 forms)
    1. growth and spread of hyphal filaments
    2. asexual production of spores
    3. simple cell division (budding yeast)
  • some fungi produces spores as a result of sexual reproduction:
    1. sexual spores: from the fusion of two haploid cells to form a diploid cell. It will undergoes meiosis to produce haploid spores (acospores, basidiospores,zygospores)
    2. spores are resistant to drying, heating, chemicals and freezing
    3. important for increasing the diversity in population
34
Q

yeast (unicellular fungi): saccharomyces cerevisiae, steps of sexual reproduction

A
  • cells are spherical to oval, cell division through budding
  • sexual reproduction: mating types in Saccharymoses cerevisiae
  1. asexual reproduction (mitosis)
  2. mating
  3. cell fusion
  4. nuclear fusion
  5. meiosis (to ascus)
  6. germination
35
Q

excavata

A

euglenids
kinetoplastids
diplomonads
parabasilids

36
Q

chromalveolata

A
  • stramenopiles

- alveolata

37
Q

opisthokonta

A

fungi

animals

38
Q

archaeplastida

A

green algae
red algae
plants

Microbiology (25 decks)

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