Taxonomy of Eukaryota Flashcards
What is done to figure out phylogeny of the eukarya
Sequencing of 18S rRNA
Relationship between 18S rRNA is ____ for eukarotes that 16S rRNA genes is for prokaryotes
Weaker
As 18S rRNA is not so reliable, what other tests are used for eukaryotes
MLST
What is secondary endosymbiosis
Uptaking eukarya by abother eukarya
Green algae are also called
Chlorophytes
Green algae are closely related to
Plants
Most green algae inhibit
Freshwater, but some are marine or terrestrial
How many flagellas green algae have
Can be one, but can be multiple
How do green algae reproduce
Sexually and asexually
Endolithic algae grow ___(place)
Inside porous rocks
Red algae are also called
Rhodophytes
Where do red algae live
Mostly marine, but some freshwater and terrestrial
Red color of red algae is coming from
Phycoerythrin
Phycoerythrin is more produced in
Cells that are living at a greater depth
Are red algae uni-, multicellular?
Most species re multicellular, some are unicellular
Example of unicellar red algae and where does it live
Galdieria, lives in hot acidic hot springs
Explain secondary endosymbioses
When green and red algae are converged from primary endosymbiosis, some cells uptook green algae and became euglenids and chlorarachniophytes, with chloroplast from green algae.
Other cells took red algae and became stramenopiles, apicomplexans, dinoflagellates
General characterization of diplomonads and parabasalids
- Unicellular
- Flagellated
- Lacks chloroplasts
- Live in anoxic environment
How many nuclei does diplomonads have
Two nuclei of equal size
What do diplomonads have instead of mitochondria?
Mitosomes
Key genera of diplomonads and what do they cause
Giardia (cause giardiasis)
What do parabasalids have to support Golgi complex
A parabasal body
As parabasalids lack mitochondria, what do they have
Hydrogenosomes for anaerobic metabolism
Key genera of parabasalids
Trichomonas
How do mitosome function
Reduced form of mitochondrion-derived from mitochondrion- that does not have enzymes of the TCA cycle and does not have respiratory chain. They are involved in the maturation of iron-sulfur clusters
What does hydrogenosome do
Present in eukaryotes whose metabolism is strictly fermentative. It carries out the oxidation of pyruvate to H2, CO2 and acetate. Sometimes H2-consuming endosymbiotic archaea are also present (methanogens-produce nethane from CO2 and H2)-primary endosymbiosis
What are cysts
Some species of protists are able to differentiate into cysts. Cysts are similar to endospores produced by prokaryotes. It protects the cells against deleterious environmental conditions. They survive long periods of starvation and/or desiccation and infection by prokaryotes
Explain the cycle of giardia lamblia
Their cysts contaminate water, food, hands, etc. When they get into the body, two trophozites are developing from one cyst. Then they divide and become cyst again. When they are excreted in stool, they contaminate the environment. Trophozoa form does not survive in the environment
What is the most common parasitic infection in developed countries
STI in himans from Parabasalids: Trichomonas vaginalis
Trichomonas vaginalis does not survive well in the environment, so how It is transmitted
Sexually
What are euglenozoans
Unicellular flagellated eukaryotes
Where do euglenozoans usually live
In aquatic habitats feeding on bacteria
What are kinetoplastids
Part of euglenozoans, that are named after kinetoplast, A mass of circular DNA present in their single, large mitochondrion
Are kinetoplastids harmful
Yes, some can cause serious diseases in humans
Explain what species of kinetoplastids are harmful and how they are transmitted and characteristics
Trypanosoma brucei.
Causes African sleeping sickness. Lives and grows 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 flag
Characterize euglena
- Nonpathogeic and phototrophic
- Contain chloroplasts, can exist as a heterotroph; will lose its chloroplast if incubated in the dark for a long time
- Can feed on bacteria by phagocytosis
Why alveolates are called like that
Because they have alveoli, the sacs underneath the cytoplasmic membrane. The may help cells to maintain osmotic pressure and get rid of waste
Representative of alveolates
Ciliates, dinoflagellates, and apicomplexans
Alveoli in paramecium are
Contractile vacuoles
Most widely distributed genera of alveolates
Paramecium
Describe ciliates
Possess cilia at some stage of their life
- Use cilia for motility and to obtain food
- Ciliates have two nuclei(macro and micronucleus)
- During conjugation-sexual reproduction-two paramecia exchange microbulcei
- Some ciliates are animal parasites, some are animal symbiotes (in the rumen)
Why ciliates have two nuclei
Macro- is the place for translation and transcription
Micro-exhange nucelus when dividing
Where do dinoflagellates live
Diverse marine and freshwater phototrophic organisms
Some are free-living and others live symbiotically with corrals
What Is particular about dinoflagellates anatomy
They have two flagella with different insertion points on the cell
- Transverse flagellum
- Longitudinal flagellum
Discuss the toxicity of dinoflagellates
- Some species secrete neurotoxins
- In warm and polluted waters, dinoflagellates can reach very high numbers
- Associated with human poisoning (paralytic shellfish poisoning). Accumulation of toxic dinoflagllates in muscles
What is the name for the dense suspensions of dinoflagellates
Red tides
Apicomplexans are obligate _____
Parasites
Life cycle of apicomplexans
- Sporozoite(transmission)
- Gametocyte (sexual reproduction)
- Other stages
Apicomplexans have apicoplasts, which are
Degenerate chloroplasts that lack pigments and phototrophic capacity, but still carry many anabolic pathways
What apicomplexans cause (disease) and by what species
Malaria (Plasmodium)
Toxoplasmosis (Toxoplasma)
Coccidiosis (Eimeria)
Explain anatomy of stramenopiles
All have flagella with many short hairlike extensions
What is the metabolism of stramenopiles
They are chemoheterotrophs and phototrophic members
Representatives of stramenopiles
Oomycetes, diatoms, golden algae, and brown algae
Characterize oomycetes
- Chemoheterotrophs
- Also called water molds-filamentous growth
- Presence of coenocytic hyphae (multinucleate)
- Cell wall are made of cellulose, nit chitin as in fungi
A species from oomycetes that caused the Irish potato famine
Phytophthora infestans
Characterize golden algae
- Also called chrysophytes
- Most are unicellular, some are colonial(form groups)
- Golden algae are named after their golden-brown color
What pigments give golden algae its color
Chloroplast pigments are dominated by the carotenoid fucoxanthin
Why diatoms are important
They are the biggest primary producers in costal waters, they make most phytoplanktons
Where do diatoms live
Freshwater and marine habitats
Diatoms are ___ cellular and ___ (type of metabolism)
Unicellular
Phototrophic
What kind of cell wall diatoms have and describe it
They have frustules: cell walls made of silica with proteins and polysaccharides attached to it. Protect against predation
When do diatoms appeared
About 200 million yeas ago
How do we distinguish cercozoans and radiolarians from other protists
By their threadlike pseudopodia
Cercozoans and radiolarians are ___ (uni/multicellular)
Unicellular
Examples of cercozoans
Foraminifera
Characterize Foraminifera
- Exclusively marine
- They form ornate shell-like structures called tests
- Tests from organic materials reinforced with calcium carbonate
Characterize radiolarians
- Mostly marine, heterotrophic organisms
- Tests are made of silica (like diatoms)
- Name is derived from radial symmetry of tests
Definition of amoebozoa
Terrestial and aquatic protists that use pseudopodia for movement and feeding (phagocytosis of bacteria and smaller protists). Move by amoeboid movement (cytoplasmic streaming)
Major groups of amoebozoa
Gymnamoebas
Entamoebas
Slime molds (microscopic slugs)
Characterize gymnamoebas
-Free-living, inhabit soil and aquatic environments
Characterize entamoebas and a representative
-Parasites of vertebrates and invertebrates (Entamoeba histolytica)
Why slime mold was grouped with fungi before?
They have similar life cycle: produce fruiting bodies with spore for dispersal, but genetically they are different
What is the property of slime mold
Motile, they can move across surfaces rapidly
Describe the life cycle of plasmodial slime molds
-Have vegetative forms that are masses of protoplasm (cytoplasm, nucleus, organelles) of indefinite size and shape (plasmodium), that contain multiple nuclei (not divided into individual cells)-2n
- From the plasmodium, a sporangium can form ,containing multiple haploid spores (dormant, resistant, for dispersal)-2n
- The spores germinate, yielding a swarmer cell (flagellated or amoeboid)-n. The fusion of two swarmer cells regenerates the diploid plasmodium
Characterize cellular slime molds- life cycle
- vegetative forms composed of single amoebae (haploid)
- Aggregate of separate amoeboid cells forms a pseudoplasmodium (slug) that can move as a 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
The example of cellular slime mold
Dictyostelium discoideum
How Dictyostelium discoideum can be used in agriculture
Somtimes they stop eating bacteria and instead incorporate them into their fruitful bodies, carrying them around and then they can seed a new food crop, which is a major advantage if edible bacteria are lacking at the new site
Most fungi are ____ cellular, forming a network of ___
Multicellular
Hyphae (mycelium)
Two types of fungi
- Ceonocytic: cytoplasm and nuclei are not subdivided into cells
- Septate: nuclei are separated by cross wall
What can hyphae do
They can extend above the surface and produce sexual spores called conidia. Conidia are often pigmented and resistant to drying
Most fungal cell walls are made of ___
Chitin
How do fungi feed
They secrete extracellular enzymes that different complex organic materials (polymers). Monomers, or short polymers are then assimilated
What is the name of symbiotic association between the fungi and the plant root and what fungi group does it
Mycorrhizae- association
Species- glomeromycetes
What do mycorrhizae help the plant roots to do
To obtain phosphorus
How does fungi obtain nutrients in symbioses
From plant
What is lichen
Association between fungi and algae/cyanobacterium
What is ectomycorrhizae and endomycorrhizae
Ecto- form a sheath around the plant root , but do not penetrate it
Endo- the fungal hyphae is embedded in the plant root
What do many fungal plant do in plant pathogens
They form pecialized hyphae-haustoria- to penetrate the plant cells and consume the cytoplasm
What is the major factor to get mycoses infection
Immunosuppresion
What is the range of mycoses infection in humans
From athlete’s foor to histoplasmosis (systemic infection)
Three forms of fungi when reproducing asexually
- Growth and spread of hyphal filaments
- Asexual production of spores
- Simple cell division
Describe sexual reproduction of fungi
-Sexual spores: from the fusion of haplod cells to form a diploid cell-> undergoes meiosis to produce haploid spores (ascospores, basidospores, zygospores)
Why sexual reproduction is important in fungi
For increasing genetic diversity in the population
Fungal spores are resistant to
Drying, heating, freezing, chemicals
Yeasts are
Unicellular fungi
Representative of yeast
Saccharomyces cerevisiae
Characterize yeast
- Cells are spherical to oval, cell division through budding
- Sexual reproduction: mating types in Saccharomyces cerevisiae
