Protists Flashcards
what is a protist
a group of organisms which are not defined as much by commonality but by exclusion- they are something which is not an animal, plant, fungus of prokaryote
give some examples of protists
amoebas
paramecia
parasites
oomycetes
when did protists emerge on earth
2 billion years ago = unicellular
750 millions years ago= multicellular
give an example of a multicellular protist and explain why they dont fit into any other classification
brown algae/ phaeophyta and kelps
- they produce pigments such as chlorophyll c and fucoxanthin which are different photosynthetic pigments than in plants
give an example of a multicellular protist and explain why they dont fit into any other classification
brown algae/ phaeophyta and kelps
- they produce pigments such as chlorophyll c and fucoxanthin which are different photosynthetic pigments than in plants
what is rhodophyta
red algae = a multicellular protist containing phycobilin pigments
why is coralline algae important
- cement the reefs providing new sites for corals to settle
- food source for alot of species
give some examples of unicellular protists
- oomycetes
- parasite plants and fish
how are cyanpbacterial blooms prevented by protists
some protists feed on bacteria, feeding on cyanobacteria decreases populatinos therefore release of toxins which deplete oxygen are prevented
how are protists used to purify waste water
- team up with aerobic bacteria in the aeration tanks to degrade organic matter
- when all nutrients are gone the protists eat the bacteria producing pure water
how are protists unique in structure
- some carry more than one nucleus
- some anaerobic protists do not have a true mitochondira
what are the two nucleus which can be found in paramecia and what do they contain
1) macronucleus= conatins many copies of genes needed for growth
2) micronucleus= essential for reproductin as it is the storage site for germline material
what is the advantage of having two nuclei
allow paramecium to divide faster as having multiple copies of the same genes means transcription of genes is faster and make proteins faster
what is schizogony
a form of asexual reproduction where a cell size increases and the nucleus and other organelles divide repeatedly which eventually ruptures producing tiny cells
what is a schizont
a type of cell formed as a result of schizogony
what mitchondrion related organelles to anaerobic protists have
1) mitosomes= have no ATP
2) hydrogenosomesw = produce ATP by reactions which generate hydrogen by-product
what mitchondrion related organelles to anaerobic protists have
1) mitosomes= have no ATP
2) hydrogenosomesw = produce ATP by reactions which generate hydrogen by-product
true or false: mitosomes and hydrogenosomes contain DNA
false - they fully rely on proteins transported from cytosol
give the names of the protists which are apart of the phytoplankton
1) coccolithophores
2) diatoms
3) dinoflagellates
what is a coccolithophore
unicellular algae which uses co2 for photosynthesis to make calcium carbonate coccolith shells which shed as it grows
they are hihgly reflective
how do coccolithophores make their calcium carbonate coccoliths
1) atmospheric co2 enters ocean and converted to organic carbon
2) reacts with sea water forming H2CO3 which dissociates to form carbonate and bicarbonate
how do coccolithophores form clouds
1) produce dimethylysulfuniopropionate (DMSP which is converted to dimethylsulfide (DMS)
2) sulphate atcs as a nucleating agent for water vapour which forms droplets and clouds
what is a diatom
a unicellular algae which is photosynthetic and abudant in aquatic environments
outline the structure of the cell wall of diatoms
made of silicon dioxide which are very tough and resistant
cotains pores to facilitate expsoure to water and co2
outline asexual reproduction in diatoms
1) the top shelf of the cell acts as a template for the bottom
2) the new bottom becomes a top and is a template for another bottom
3) the new new bottom becomes a top and another bottom is made, each divison making cell smaller
4) when shell is too small the ell exits the shell undergoes meiosis forming gametes which fuse to form a zygote which grows a new shell
what are dinoflagellates
protists with a shell made of cellulose, some of which are photosynthetic and others heterotrophs
what is paramecia
a ciliate which use cilia to move around and inhabit pond waters, lakes and soils which also prey on other organisms
how do paramecia use cilia
1) cilia aligned in rows and move like whips to propell cell = MOVEMENT
2) use to sweep food into gullet where food is digested in vacuoles and waste leaves via anal pore
how can paramecia become toxic to predators
bacterial symbiosis
- swallowing bacteria which produce toxins which the paramecia are resistant to but other species are not
what is a plasmodium
a type of protist in the apicomplexa and is the main cause of malaria
- five species
- alternates between two life stages in the vector and host
outline the life cycle of the plasmodium in the vector
1) female mosquito feeds o a host infected with malaria and aquires the parasite and exit RBC
2) male and female gametes form zygotes which invade the gut
3) zygotes differenciate into n oocytes which enter the hemolymph
4) oocytes develop into sporozoites and travel to salivary glands
outline the plasmodium life cycle in the host
1) sporozoites travel to liver
2) here it can remain dormant or multiply
3) sporozoites mature into schizonts (multinuclated cells)
4) cells enter RBC where they mature into ring shaped forms
how do plasmodium parasites avoid being destroyed in the host
1) form knob like structures causing infected cells to adhere to blood vessels to avoid destructin by the spleen
2) RBC dont have lysosomes so cant be digested
what are labyrinthulomycetes
aquatic microorganisms which produce a network of filaments which act as tracks for nutients to glide to them
what are the two main groups of labyrinthuylomycetes
1) slime nets= grow network of slime tubes containing motile cells
2) thraustochytrids= grow as zoospore producing thalli
