Flashcards in 27.2 Eukaryotic Origins Deck (15)
what do chloroplasts in plant cells closely resemble?
certain photosynthetic bacteria, specifically cyanobacteria
an organism that lives in closely evolved association with another species
close interaction between species that live together, often interdependently
a symbiosis in which one partner lives within the other
based on Merezhkovsky's hypothesis and Margulis findings, where did chloroplasts originate?
chloroplasts originated as symbiotic cyanobacteria that through time became permanently incorporated into their hosts
what was the deciding evidence in support of chloroplasts' being descendants of symbiotic cyanobacteria that lived within eukaryotic cells?
the DNA of chloroplasts is independent and different from nucleotides of the nuclei of photosynthetic eukaryotes but match with those of cyanobacteria
eukaryotes were able to acquire photosynthesis because...
they could engulf and retain cyanobacterial cells
what is a common symbiotic relationship in the eukaryotic domain?
symbiosis between a heterotrophic host and a photosynthetic partner
mitochondria also originated as endosymbiotic bacteria from...
mitochondria/chloroplast genomes are greatly reduced compared to bacteria because:
genes from the original bacteria endosymbiont migrated to the nucleus
what eukaryotic organisms don't contain mitochondria?
single-celled eukaryotic organisms found in oxygen-free environments
many eukaryotes that lack mitochondria contain small organelles called:
hydrogenosomes that generate ATP by anaerobic processes. hydrogenosomes are basically highly altered mitochondria adapted to life in oxygen-poor environments
other anaerobic eukaryotes contain smaller organelles called:
mitoses that also appear to be remnant mitochondria; only has genes needed for assembling the clusters of iron and sulfur found in many proteins
nuclear genes in Eukarya resemble those of Archaea because:
primoridal eukaryotic host cell was closely related to Archaea