microbial diversity Flashcards
how big are microbes?
less than 1mm/ microscopic
how long have microbes been on earth?
3.8 billion years
hydrothermal vents as the origin of life
life arose from gases (H2, CO2, N2, and H2S) with energy from harnessing geochemical gradients created at a special kind of deep-sea hydrothermal vent
Compartments or inorganic vesicles created in alkaline deep sea vents could have produced chemical gradients very similar to the proton gradients seen in the membranes
lipid membranes as the origin of life
Synthesis of phospholipid vesicles could have enclosed the replication and biochemical reactions
feeding methods of bacteria and archaea
feed by absorption of nutrients
feeding methods of protists
feed by engulfing particles or other organisms or by photosynthesis
fungi feeding methods?
Osmotrophs
Carl Woese (1970s)
pioneered the use of ribosomal RNA (rRNA) sequencing and devised the concept of three domains of life
where is 16s Ribosomal RNA found?
Found in all bacteria and archaea, eukaryotes have in chloroplasts and mitochondria.
3 pieces of evidence supporting the Endosymbiotic theory for evolution of eukaryotic cells
organelles have a small genome
cyanobacteria are the ancestors of chloroplasts
alphaproteobacteria are the ancestors of mitochondria
secondary endosymbiosis led to the increasing diversification of eukaryotes
the ‘original host’?
Asgard Archaea
what are Stramenopiles?
‘well known’ algae
- micro/diatoms
-macro/kelps
where are Stramenopiles /Diatoms more productive?
in temperate and polar regions
what are stramenopiles enclosed in?
hard silica (SiO2)
‘shell ike’ structure
FRUSTULE
What are the two major lineages in Haptista?
Haptophytes
centrohelids
where can you find Haptophytes?
marine
where can you find Centrohelids?
freshwater
Haptophytes outer layer?
covered with external scales or plates called coccoliths
made of calcium carbonate
what do Archaeplastids contain?
primary plastids from endosymbiosis with a cyanobacterium
three major Alveolates groups
Cilliates
Dinoflagellates
Aplicomplexans
how many species of ciliates?
over 8000
ciliates feeding method?
Synchronous beating creates water currents to channel particulate food into the cell
dinoflagellates feeding method?
extend a “feeding veil” (pallium) with which they surround large prey and secrete digestive enzymes extracellularly
what are Apicomplexans?
unicellular eukaryotes that are obligate parasites of other eukaryotes
major 2 groups of Rhizarians
- Foramaminiferans
- Acanthareans
when can bacteria be considered the same species?
(1) they have more than 70% DNA-DNA hybridization
(2) their 16SrRNA gene sequences are more than 97% similar
(3) they share a high degree of similarity, with characteristics
that distinguish them from other species
where is Synachococus mainly found?
in the top 20m in nearly all surface waters
Prochlorocococcus’ pigments harvest what colour of light?
blue
the most prominent nitrogen fixer in tropical and subtropical oceans (50% of surface waters)
Trichodesmium
what do some anaerobic SOB use as an electron acceptor?
nitrate
what does ‘SOB’ mean?
‘Sulfur oxidising bacteria’
distribution of gammaproteobacteria/vibrios?
worldwide distribution in coastal and ocean water and sediments
uncultured Vibrionaceae in Anglerfish cause?
their light
what do Psychropiezophilic oceanospirillales do?
degrade complex organic compounds
(collagen, cholesterol and lipid from bones)
what does ‘OHCB’ stand for?
Obligate hydrocarbonoclastic bacteria
purpose of Obligate hydrocarbonoclastic bacteria
involved in the mineralization of hydrocarbon pollutants
production of methane
methanogenesis
what does viral lysis lead to an increase of?
increased bacterial production and respiration
