eukaryotes Flashcards
origins of eukaryotes
side branch of archaea
primary feature of eukaryotes
their nuclear material (DNA) is bound within a membrane the nuclear envelope
3 domains of life
bacteria, archaeans, eukaryotes
how did eukaryotes arise (serial endosymbiosis theory)
in a ancestral prokaryote (archaen) cell the plasma membrane infolded which eventually surrounded the nucelar material and became endomembrane components such as nucelus and endoplasmic recticulum, this cell then engulfed an aerobic bacterial cell which became the mitochondria. It then engulfed a photosynthetic bacterial cell which became the chloroplast.
what is some evidence of endosymbiotic theory
-occurs even now
-mitochondria and plastids have their own genomes
-similar plastids appear in diverse lineages of single celled eukaryotes
-genetic sequence of DNA in mitochondria is similar to that of some prokaryotes
do mitochondria and bacteria have many similarities
yes
similar DNA,, enzymes, inner membrane transport systems, size and morphology, division, protein synthesis machinery, etc
example of endosymbiosis today
the termite called mastotermes darwiniensis
has flagellated single cell eukaryote in its hindgut mixotricha paradoxa that assist in digesting cellulose form plant cell walls
this cell is actually 5 different species living together to form this cell
genomes 1 is mixotricha itself
genome 2 and 3 are prokaryotes that function as mitochondria (mixotricha has lost its OG mitochondria)
genome 4 and 5 are bacteria that function as cilia on cell surface
endosymbiont
organism that lives within another organism
around how many single celled eukaryote species are there
100 000 to 200 000
autotrophy
ability to be self sustained by producing food from inorganic compounds
heterotrophy
food is sourced from organic compounds
single celled eukaryotes are unicellular although
some are simple colonial forms
are single celled eukaryotes autotrophic or hetertrophic
can be both, but many are heterotrophic
how are single celled eukaryotes groups or clades classified
-molecular sequence
-cell ultrastructure
-presence/ absence of locomotory structures
-presence absence of mitochondria and plastids
-structure of membrane
