5. Taxonomy - Eukaryotes Flashcards
- how to infer the phylogeny of eukarya?
- relationship btw 18S rRNA genes is stronger/weaker for eukaryotes/prokaryotes than 16S rRNA genes is for eukaryotes/prokaryotes
- consequences? (3 ish)
- sequencing of 18S rRNA (smaller subunit of ribosome) genes!
- relationship btw 18S rRNA is WEAKER for eukaryotes than 16S rRNA genes is for prokaryotes
- phylogenies have been constructed by taking into account other genes (e.g., tubulin, RNA polymerase, and ATPase) –> MLST (multi-locus sequence typing)
- New insights have arisen because of these new phylogenies (e.g., fungi and animals are closely related and they are close to the amoebozoa).
- eukaryotic molecular phylogeny is still being refined.
ARCHAEPLASTIDA
RED ALGAE
- also called what?
- marine, freshwater or terrestrial?
- red color is from what?
- are all red algae red?
- unicellular or multicellular
RED ALGAE
- rhodophytes
- mostly marine but some freshwater and terrestrials
- from phycoerythrin (accessory pigment) –> at greater depth, more phycoerythrin is produced by cells
- not all species produce phycoerythrin! ie galderia partitata is green
- most species are multicellular (ie not a microorg) but some are unicellular (ie galdieria)
ARCHAEPLASTIDA
GREEN ALGAEA
- also called what?
- closely related to what?
- marine, freshwater or terrestrial?
- unicellular or multicellular
- sexual or asexual reprod?
- grow inside what?
- also called chlorophytes
- plants
- mostly freshwater, but some are marine (ice, snow) and terrestrial (soil with lots of water)
- can be unicellular (usually flagellated: ie chlamydomonas) to multicellular (ie volvox: big colony, when its too big, makes small colonies inside big colony and then explode)
- both sexual and asexual
- endolithic algae grow inside porous rocks (in little cavities)
explain primary vs secondary endosymbiosis + role of red and green algae ish
PRIMARY ENDOSYMBIOSIS
- cell of eukarya merges with cell of cyanobacteria lineage of bacteria –> creates red and green algae (that have choroplasts)
SECONDARY ENDOSYMBIOSIS:
- red and green algae diverge as separate lineages –> each merge into a “bigger cell” (just like cyanobacteria did) and evolve inside that cell to create a new cell
- ie the red and green algae become chloroplasts in other cells
do all eukaryotes have mitochondria? –> what are they called?
- instead, what do they have (2)
Amitochondriate eukaryotes
- Eukaryotes that lack a mitochondrion. At first, they looked like very primitive eukaryotes.
*typically live in anoxygenic environment
MITOSOME:
- reduced form of mitochondrion – derived from mitochondrion – that does NOT have enzymes of the TCA cycle and does NOT have a respiratory chain
- are involved in the maturation of iron-sulfur clusters.
HYDROGENOSOME
- present in eukaryotes whose metabolism is strictly fermentative.
- carries out the oxidation of pyruvate to H2 (byproduct), CO2 and acetate.
- Sometimes H2-consuming endosymbiotic bacteria are also present (methanogens –> consume H2) – secondary endosymbiosis.
*amitochondriate eukaryotes usually have either mitosome or hydrogenosome
- some species of protists are able to differentiate into ___A____, becoming ________
- ___A____ are similar (but not the same) as WHAT
- 3 functions ish
- metabolically active?
CYSTS! becoming encysted (especially when conditions are bad)
- cysts are similar to endospores produced by prokaryotes
1) Protect the cells against deleterious environmental conditions.
2) Survive long periods of starvation and/or desiccation.
3) Survive infection by prokaryotes.
*no (?)
DIPLOMONADS and PARABASALIDS
- bacteria, archaea or eukarya?
- uni or multicellular?
- flagella?
- lacks what?
- oxic or anoxic habitats?
DIPLOMONADS
- smtg special about nuclei
- have mitochondria?
- form cyst?
- key genera?
PARABASALIDS
- contain a _________ body
- have mitochondria?
- form cysts?
- live where?
- key genera?
- EUKARYA!
- unicellular
- flagellated
- lacks chloroplasts
- anoxic habitat
DIPLOMONADS
- Have two nuclei of equal size
- Have mitosomes (degenerated mitochondria)
- yes!
- Key genera: Giardia (cause giardiasis)
*typically parasites of other cells (like GI tract) –> no O2 there
PARABASALIDS
- Contain a parabasal body (structural support to the golgi complex)
- Lack mitochondria, but have hydrogenosomes for anaerobic metabolism
- does NOT form cysts –> does not survive well outside host (adapted to sexual transmission)
- Live in the intestinal and urogenital tracts of animals as parasites or symbionts.
- Key Genera: Trichomonas
*trichomonas vaginalis –> STD in humans: most common parasitic infection in developed countries
EUGLENOZOANS
- unicellular or multicellular?
- flagella?
- bacteria or eukaryote?
2 types:
a) KINETOPLASTID
- why named like that?
- aquatic or terrestrial habitat
- can cause disease in humans? explain!!!
b) EUGLENIDS
- cause disease in humans?
- heterotroph or phototroph?
- contain chloroplast?
- can feed on what?
- unicellular, flagellated eukaryotes
KINETOPLASTID:
- named for presence of kinetoplast (K) (marker of philogeny) –> mass of DNA in single large mitochondrion
- live primarily in aquatic habitats feeding on bacteria
- some species cause serious diseases in humans –> like African sleeping sickness (chronic, usually fatal infection, transmitted by tsetse fly) –> lives and grows in bloodstream + infects CNS during lager stage
*single flagellum is enclosed in membrane flap –> bent = like a fin = super powerful = can break through BBB
EUGLENIDS
- nonpathogenic!
- phototrophic
- contain chloroplasts –> can exist as heterotrophs tho –> will lose its chloroplast if incubated in dark for a long time
- can feed on bacteria by phagocytosis (mixotroph)
*typically has flagella
ALVEOLATES:
- characterized by presence of (what)?
- (what) may function to help cells maintain what?
- (what) –> called what in Paramecium?
- 3 subtypes ish
- of ALVEOLI! –> water pump –> gets water out of cell (video!)
- alveoli –> may function to help cells maintain osmotic balance
- paramecium: called contractile vacuole bc it contracts
1. ciliates
2. dinoflagellates
3. apicomplexans
ALVEOLATES:
a) CILIATES
- possess what? use it for what? have how many nuclei?
- shape?
- what is the most widely distributed genera?
- during conjugation/sexual reproduction, what is exchanged?
- some ciliates are ______ _______ vs some are _______ ________ vs some are also what?
b) APICOMPLEXANS
- contain what? function? but can still carry what?
- free-living?
- key species?
- some of them have what?
a) CILIATES
- possess cilia at some stage of their life –> for motility and to obtain food –> 2 nuclei! (macronucleus and micronucleus)
- pear/oblong shape
- paramecium
- 2 paramecia exchange micronuclei
- animal parasites or animal symbionts (in rumen) (or also free living)
b) APICOMPLEXANS:
- apicoplasts –> degenerate chloroplasts that lack pigments and phototrophic capacity BUT still carry many anabolic pathways (just not photosynthesis anymore)
- evolved into obligate parasites of animals
- plasmodium falciparum (cause malaria)
- have very complex life cycles!!
*this is a subtype of what?
DINOFLAGELLATES
- special characteristic?
- diverse ______ and _______ _____trophic organisms
- free-living?
- what is special about them? explain
alveolates!
- have 2 flagella with different insertion points on the cell –> transverse flagellum (goes around cell: allows cell to orient/turn) + longitudinal flagellum (extend away from cell = propellor)
- diverse marine and freshwater phototrophic orgs
- free-living and others live symbiotically with corals
*some species secrete neurotoxins! in warm and polluted waters, dinoflagellates can reach very high numbers –> dense suspension of these cells are called red tides (also fish can become red from bioaccumulation)
*associated with human poisoning (paralytic shellfish poisoning) –> accumulation of toxic dinoflagellates in mussels (filters! & concentrates toxins inside themselves)
STRAMENOPHILES:
- special characteristic?
- how to they make energy? _____ trophs or _______ trophs
- 4 subtypes + how do they make energy
- all have FLAGELLA with many short hairlike extensions –> make them look like brooms, good for mobility
- chemoheterotrophs and/or phototrophic
- oomycetes –> chemoheterotrophs
- diatoms –> phototrophs
- golden algae –> phototrophs
- brown algae –> NOT unicellular
DESCRIBE
*what phylogeny are they?
a) oomycetes
- metabolism
- look like what?
- main charac?
- name a species –> causes what?
b) diatoms
- metabolism
- a lot of species?
- live in what habitat?
- main charac?
- appeared on Earth when?
c) golden algae
- metabolism?
- what dominates?
- also called what?
- mostly unicellular or not unicellular?
Eukarya –> stramenophiles!
OOMYCETES
- chemoheterotrophs
- water molds based on their filamentous growth + presence of coenocytic hyphae (multinucleate)
- CELL WALLS MADE OF CELLULOSE (not chitin as in fungi)
- phytophthora infestans causes late blight disease in potatoes and contributed to Irish potato famine
DIATOMS
- unicellular, phototrophic
- over 100 000 species of diatoms
- freshwater and marine habitats
- frustules: cell walls made of silica (essentially glass = hard shell) –> with protesin and polysacs attached to it –> protect against predation
- appeared on Earth about 200M years ago
GOLDEN ALGAE
- phototrophs
- chloroplast pigments dominated by carotenoid FUCOXANTHIN = main charac –> named for their golden-brown color
- also called chrysophytes
- mostly unicellular, some are colonial
BROWN ALGAE
- not unicellular
CERCOZOANS AND RADIOLLARIANS
- distinguished from other protists by WHAT
a) example of cercozoan?
- exclusively what habitat organisms
- form what-like structures called ________ –> made from what? reinforced with what?
b) radiolarians:
- mostly what habitat?
- also have same structure as cercozoans –> made of what?
- name is derived from what?
- threadlike pseudopodia (extension of cytoplasm –> not filaments, filled with actin)
a) Foraminifera - exclusively marine orgs
- form shell-like structures called tests
- made from organic materials (protein) reinforced with calcium carbonate
b) RADIOLARIAN - mostly marine, heterotrophic organisms
- tests are made of silica
- name is derived from radial symmetry test
AMOEBOZOA
- what habitat?
- use WHAT for movement and feeding?
- move by ______ movement
- 3 major groups? describe first 2
- terrestrial and aquatic protists
- use peudopodia (extension of cytoplasm) for movement and feeding –> phagocytosis of bacteria and smaller protists)
- move by amoeboid movement –> cytoplasmic streaming
a) gymnamoebas:
- free-living, inhabit soil and aquatic environments
- prey on other orgs
b) entamoebas:
- parasites of vertebrates and invertebrates (ie entamoeba histolytica)
- typically of GI tract or cause eye infection
c) slime mold
SLIME MOLD
- what phylogeny?
- previously grouped with WHAT? why?
- can move rapidly?
- difference between cellular slime mold and plasmodial slime mold? general
- eukarya: amoebozoa
- with fungi bc have similar life cycle: produce fruiting bodies with spore for dispersal
*multicellular behaviour but is unicellular! - motile! can move across surfaces rapidly –> use cytoplasm with pseudomodia
CELLULAR SLIME MOLD
- ie dictyostelium
- different cells!
- grows in direction it wants to go!
PLASMODIAL SLIME MOLD
- ie Fuligo
- 1 big cell with multiple mitochondria, ribosome, Golgi, nuclei
- can be found in pieces of rock
describe cellular slime mold life cycle
- WHAT
- 4 steps
- exhibit what behaviour?
- vegetative forms composed of single amoebae (haploid)
1. aggregate as pseudoplasmodium (slug) and can move as a single unit (cells do NOT fuse). all cells are separated
2. fruiting body is formed, cells differentiate into spores –> spore germinates
3. may form diploid macrocysts (diploid) that undergo meiosis to form new amoebae (haploid): sexual reproduction
4. amoebaes aggregate into structure called a slug (when conditions go bad) –> migrate until aggregate forms a fruiting body at the end of a stalk
*exhibit intelligence bc groups behaviour/social org –> get together to form slug, then form spores
describe plasmodial slime molds life cycle
- WHAT?
- 3 steps. what happens when no more food?
- have vegetative forms that are masses of protoplasm of indefinite size and shape (plasmodium) that contain multiple nuclei
*no separation btw dif cytoplasm and dif parts –> 1 cell with many nuclei
1. if no more food: from the plasmodium, a sporangium can form, containing multiple haploid spores (dormant, resistant, for dispersal)
2. the spores (haploid) germinate, yielding a swarmer cell (flagellated or amoeboid, can convert btw the 2)
3. fusion of 2 swarmer cells (sexual reproduction) regenerates the diploid plasmodium
what are 2 cool things that amoebas can do?
- can do “agriculture” –> grow “food”/microorgs inside their bodies
- pack hunting by common soil amoeba on nematodes –> can hunt like wolves
FUNGI
- includes (3)
- most fungi are uni or multicellular? forming a network of ___A___ (_________)
- 3 types of ___A_____
- most fungal cell walls are made of WHAT?
- how to they feed?
- yeasts, molds and mushrooms
- multicellular, forming a network of hyphae (mycelium)
a) Coenocytic (nonseptate) hyphae –> cytoplasm and nuclei are NOT subdivided into cells (a bit like plasmodial slime)
b) septate hyphae: nuclei are separated by cross wall
c) pseudohyphae: usually unicellular but bc how they replicate (budding) –> daughter cell doesnt completely detach… - chitin
- feed by secreting extracellular enzymes that digest complex organic materials (ie wood) (polymers). monomers or short polymers are then assimilated through transport
what are 4 ways that most fungi reproduce? asexual or sexual?
- growth and spread of hyphal filaments
- simple cell division (budding yeast)
- asexual production of spores
- sexual production of spores
*first 3 are asexual
ASEXUAL PRODUCTION OF SPORES:
- in many species, _______ that extend above the surface can produce a ___B____, which contains asexual/sexual spores called ____A____
- ____A_____ are often _________ and resistant to __________
*where can we see ___B____ in real life?
- hyphae –> produce sporangium –> contains asexual spores called conidia
- conidia are often pigmented and resistant to drying
*mold on bread + sporangium! don’t écraser –> will spread everywhere in the house
SEXUAL PRODUCTION OF SPORES
- sexual spores can originate from fusion of WHAT to form WHAT –> then undergo WHAT to produce WHAT (3 types)
- spores are resistant to (4)
*some fungi produce spores as a result of sexual reproduction
- sexual spores can originate from fusion of 2 haploid cells to form a diploid cell that then undergo meiosis to produce haploid spores (ascospores, basidiospores, zygospores) (dif ways of packaging spores)
- resistant to drying, heating, freezing and chemicals
*schéma!
saccharomyces cerevisiae
- cells are what shape?
- cell division through what?
- sexual or asexual reproduction? explain
- spherical to oval
- through budding
- sexual!
1. asexual reproduction (mitosis): alpha and A type cell division (1n)
2. mating: 1 alpha and 1 A type –> cell fusion –> nuclear fusion to form a diploid cell (2n)
3. meiosis –> ascospores (haploid) (not metabolically active spores) –> germination so that they are active
SYMBIOSES:
- ________ origin from the association of which 2 organisms?
- some species of fungi (_________) form close relationships with ____A______
- _____A_____ help plant roots obtain what? (2) –> describe the 2 types
- LICHENS origin from association of 2 orgs: fungus and a phototrophs (cyanobacteria or green algae)
- some species of fungi (glomeromycetes) form close relationships with plant roots (mycorrhizae) –> really symbiotic relationship!
- mycorrhizae can help plant roots obtain phosphorus and other nutrients
a) ectomycorrhizae: form a sheath around plant root but does NOT penetrate it - endomycorrhizae: fungal hyphae is embedded in the plant root –> ENDO = inside!
PATHOGENESIS
- fungi can cause _______ in plants and animals
- many fungal plant ______ form specialized ________ (called what) –> to do what? (3 ish)
- _________ in humans range in severity from “athlete’s foot” to WHAT
- WHAT is a major risk factor?
- DISEASE!
- many fungal plant pathogens form specialized hyphae (haustoria) to penetrate the plant cells and consume cytoplasm –> cause disease!
- MYCOSES in humans range in severity from athlete’s foot to histoplasmosis
- immunosuppression! (ie HIV)
*ie candida albicans invading human oral mucosa
