13 - eukaryote origin and diversity Flashcards
what is phylogeny?
evolutionary history of a group of organisms
can be inferred indirectly from nucleotide or amino acid sequence data
whats the most widely used phylogenetic marker?
small subunit ribosomal rRNA
• SSUrRNA
what is the SSUrRNA the most widely used phylogenetic marker?
found in all domains of life
functionally constant
sufficient conserved
what are the different types of rRNA?
16S rRNA in prokaryotes
18S rRNA in eukaryotes
12S rRNA in mitochondria and plastids
the archezoa hypothesis
the nucleus was invented before the mitochondria was acquired
first eukaryotes were anaerobes
when would the archezoa hypothesis fall?
if we find:
• archezoans brach among aerobic species with mitochondria
• mitochondrial genes on archezoan genomes
• mitochondria-derived organelles in archezoans
what are hydrogenosomes and mitosomes?
homologues to mitochondria
what are the 5 main groups of archezoa?
- opisthokonta
- amoebozoa
- excavata
- archaeplastida
- SAR - stramenopiles, alveolates, rhizaria
transport into the mitochondria
mitochondria protein translocators
• TOM - outer membrane
• TIM - inner membrane
cell dies without iron sulphur cluster biosynthesis
what are hydrogenosomes?
- produce hydrogen
- produce ATP through substrate level phosphorylation
- some have a genome with mitochondria signature
- nuclear genome encodes reduced fractions of hydrogenosomal/mitochondiral protein sets
what are mitosomes?
- reduced in size
- no evidence for any capacity to produce ATP
- no genome
- nuclear genomes encode reduces mitosomal/mitochondrial protein sets
occurrence of hydrogenosomes and mitosomes
all mitochondria-like organelles derive from the same endosymbiotic event
hydrogenosomes and mitosomes evolved atlas 3 -4 times independently from mitochondria
where do eukaryotes with reduced versions of mitochondria live?
anaerobic, microaerophillic habitats
intracellular habitats
mitochondria and Fe-S cluster biosynthesis
mitochondria possess a protein machinery mediating Fe-S suer biosynthesis
the only essential metabolic function of yeast mitochondria
what are Fe-S clusters?
- small co-factors
- prosthetic group of many proteins
- found in all cellular life forms
- thought to represent some of the earliest catalysts
- require complex protein machineries for biosynthesis
