lec 4 Flashcards
what is the taxonomic group protists
-unranked, paraphyletic groupings of eukaryoties
-not plants, animals, or fungi
what are the two reasons kingdom protista given up on?
1) taxon not monophyletic
2) molecular divergencea
how many recognized phyla of protists
6 to 50
how are protists classified
-general morphology, modes of movement, modes of reproductions
-groupings of convenience
how many known species protists
73000
what is predicted true richness of protists
140000 to 1.6 millski
what is cellularity of protists
vast majoroty are unicellular or colonial
what protists are multicellular
most red algae and some green algae
asexual reproduction methods protists
binary fission
multiple fission
plasmotomy
binary fission
cell nucleus duplicates mitotically and then cell splits
multiple fission
nucleus undergoes several mitotic divisions before dividing into multiple
daughter cells with their own nucleus
plasmotomy
multinucleate (but still single-celled) individual splits into two
or more multinucleate daughter cells
similar to budding or fragmentation
opalinid symbionts of amphibians life cycle
both sexual and asexual plasmotomyreproduction
size of most protists
100-200 μm
skeletal structure created by protists metabolic activity
autogenic skeleton
skeleton made of other materials glued together
by the protist
allogenic skeleton
endosymbiosis
does it happen in protists
many instances among protists
-capture of aerobic proteobacterium by pre eukaryotic cell w membrane bound nucleus
bacterium–> mitochondrion
primary endosymbiosis
capture of free-living
bacteria by eukaryotes
secondary endosymbioses
capture of a eukaryotic cell by a eukaryotic
cell
photosynthetic plastid origin
ancient primary endosymbiosis bw heterotrophic
eukaryote and a photosynthetic cyanobacterium
what are the remenants of endosymbiosis by cryptomonads and chlorarachniophytes
-nucleus and nuclear genome of
their eukaryotic algal endosymbionts
-retain a total of four cell membranes around the
photosynthetic plastid
another word for nucleus
nucleomorph
types of locomotion in protists
some sessile
most are either sedentary or mobile
planktonic
float without much control over
their lateral direction
pseudopodia
temporary
cytoplasm-filled extensions of
the cell used for locomotion
and prey
pseudopodia most common in
Amoebozoa
2 main types of
pseudopodia
lobopodia
axopodia
lobopodia
blunt, thick extensions
axopodia
thin, rigid, supported by microtubules
what can cytoplasm in cell be like? (2)
fluid endoplasm
thick and gel-like ectoplasm
Ciliata has a distinct
abundance of cilia
photoautotrophic protists feeding
sunlight, water and carbon dioxide to make
their own carbohydrates
heterotrophic protists
feed on other
organisms
mixotrophic protists
can feed on others or make their own carbohydrates
in feeding, ____move water and particulate matter
towards the _____
cillia, cytostome
phagocytosis
solid food particles are surrounded by a
vacuole in
which they are digested
pinocytosis
dissolved material via very
small vesicles that open at the cell membranes
surface
food vacuole
digestion of solid
particles
contractile vacuoles
accumulate and
expel excess water
contractile vacuoles are more prominent
in
freshwater protists
solute
concentrations in their cytoplasm is often
higher than in the surrounding water(prolly dont have 2 know)
Phyla Diplomonadida and
Parabasalida unique features
- lack mitochondria, but had them originally(no use in anoxic enviro)
- anoxic habitats such as
stinky substrates and animal guts
what phyla and genus causes beaver fever
diplomonad, Giardia
parabasalids include
hypermastigote protists, some endosymbionts of insects
what help hypermastigotes swim
ectosymbiotic spirochaete
bacteria associated w cell membrane
Phylum Euglenida distinct features
-pellicle
-move using their flagella
-red light detecting eyespot for finding areas for photosynthesis
phylum Kinetoplastida
move using flagella that create broad undulating membrane
-kinetoplast
kinetoplast
single, large mitochondrion with a high concentration of mtDNA
what cause sleeping sickness? what phyla
trypanosomes, kinetoplastida
ciliata distinctive features
complex, directed, animalike movement
(even though single celled)
macro and micronucleus
micronucleus
diploid involved in sexual reproduction
macronucleus
hyperpolyploid
many copies of the genome that is involved in metabolism
Phylum Choanoflagellata distinctive features
cell has a collar of interconnected
microvilli surrounding single flagellum
Choanoflagellata collar and flagellum function
beating of the flagellum draws water in
through the collar, which acts as a filter, removing food to be later phagocytosed
how are choanoflagellata related to animals (3)
-look like the collar
cells of sponges
-colonial tendencies suggests origin of multicellularity
-molecularly fall out near base of metazoa
newly discovered choanoflagellate movement
-move by flexing an entire
sheet of cells up and down
-response to light levels
