Origins of the Eukarya Flashcards
What are the 3 domains
Archaea, Bacteria and Eukarya
Engulfment of Rickettsiaceae
Endosymbiotic engulfment of a red
member of the “Cyanobacteria” e.g Synechococcus
Endosymbiotic engulfment of a green
member of the “Cyanobacteria” e.g Prochlorococcus
Form mitochondria
Form rhodoplasts, leading to the lineage
of the Rhodophyta.
Form chloroplasts, leading to the
linnages of the Viridiplantae and the
Chlorophyta.
What is a close-relative of the ancestor of all Eukarya and facts about it?
Candidatus Prometheoarchaeum syntrophicum
* found in deep-sea sediment in a hydrothermal region.
* obligate anaerobe – ferments amino acids – does not respire.
* grows at 20 °C but extremely slow-growing.
* 0.5 μm diameter coccus with unusual protrusions which gives a large surface area for symbiont to stick to methanogenium sticks to tendrons.
* grows in syntrophy with Methanogenium
* mainly has isoprenoid lipids based on phytanes.
What is syntrophy?
One species (especially bacteria) feeding on the metabolic products of another species to cope up with the energy limitations by electron transfer.
How does Candidatus Prometheoarchaeum syntrophicum ferment.
fermentation = partial oxidation without using molecular oxygen/respiratory chain – ATP is generated by substrate-level phosphorylation and NAD(P)H by dehydrogenase enzymes.
What is Methanogenium?
Methanogenium is a genus of obligate anaerobes that respire CO2 as their terminal electron acceptor growing chemolithoautotrophically on H2 as its electron donor – this combination is called methanogenesis:
CO2 + 4H2 → CH4 + 2H2O
(makes methane)
What is Rickettsia and its pathologies transmitted by arthropoda?
(closest organism to mitochondria)
- Rickettsia prowazekii causes typhus.
- Rickettsia rickettsii causes Rocky Mountain spotted fever.
- Orientia tsutsugamushi causes scrub typhus.
Ehrlichia – infects various Animalia e.g. - Ehrlichia ruminantium causes heartwater.
- Ehrlichia canis causes canine monocytic erhlichiosis.
[another family of the Rickettsiales contains insect pathogens such as
Wollbachia spp. which can be used in biological pest control]
Almost always spread by ticks (Insects)
chemolithoautotrophic Bacteria
obtain their biomass from carbon dioxide
(-autotrophic), like plants.
* obtain their reducing power from an
inorganic donor (-litho-),but use
reduced sulfur species and yield sulfate.
* obtain their energy from reactions coupled
to the oxidation of chemical species
(chemo-) but use reduced sulfur species and yield sulfate.
ancestral Rickettsiaceae and their respiration reaction
2H2 + O2 → 2H2O
- this generates proton motive force (Δp) used to generate ATP and NADPH.
- ATP and NADPH are used to assimilate CO2
into biomass (inc. amino acids) this also requires ammonium ions (NH4 as biomass = C12H24O6N3 - could probably also split HCOOH into CO2
and H2 using a formate dehydrogenase.
What is the reaction catalysed by all hydrogenases?
H2 → 2H+ + 2ε-
What did the cytoplasm and periplasm of the ancestor of mitochondria evolve into?
Cytoplasm became the mitochondrial matrix and the
periplasm became the intermembrane space.
ancestral Rickettsiaceae and ancestral Ca. Prometheoarchaeum
Ancestral Ca. Prometheoarchaeum used the amino acids from ancestral Rickettsiaceae and made → CO2 + H2 + HCOOH + NH4
Give an example of each a green, yellow and red member of the “Cyanobacteria” and describe the secondary chloroplasts and
- the chloroplasts of the Viridiplantae are descended from green “Cyanobacteria” e.g. Prochlorococcus.
- the yellow chloroplasts of the Ochrophyta were descended from an unknown lineage of the “Cyanobacteria” that presumably contained fucoxanthin.
- the rhodoplasts of the Rhodophyta are descended from the red/pink/brown “Cyanobacteria” e.g. Synechococcus.
- the secondary chloroplasts of e.g. Euglena spp. (flagellates) are descended from Chlorophyta that were engulfed by other Eukarya.
