protists structure and environment Flashcards
protozoan
single celled microscopic animal of a group of phyla of the kingdom protista, such as an amoeba, flagellate, ciliate or sporozoan
definition of a protist
is any eukaryotic organism that is not an animal, plant or fungus. The protists do not form a natural group, or clade, but are often grouped together for convenience, like algae or invertebrates.
microtubules are known as
conserved structures
what are microtubules made up of
alpha and beta tbuln
investigation of alpha tubular phylogeny shows that eukaryotic organisms can be divided into three classes:
1) animal parabasalids, plant-protists, and the diplomonads
role of microtubules
1) cell shape
2) chromosome movement and cell division
3) cell motility (cilia and flagella)
difference between flagella in bacteria and protists
in bacteria: energy from proton pump in membrane
in protists: energy rom ATPase dynein
microfilaments
another cytoskeletal structure
- 7nm in diameter
- polymers of actin
- maintaining and chasing cell shape
6 main groups of protists
Opisthokonts Excavates Archaeplastids Amoebozoa CCTH SAR (stramenopiles, alvolates, rhizaria)
mitochondria in Opisthokonts
flattened cristae
mitochondria in Excavates
mitochondria discoba- lacking ‘classical’ mitochondria
mitochondria in Archeoplastids
plastids
mitochondria in Amoebozoa
mitochondria with irregular cristae
two ways in which protists feed
pinocytosis and phagocytosis
pinocytosis
- the uptake of nutrients present in solution
- characteristic of protists without a differential oral cavity
- unlikely that dissolved nutrients are utilised by free-living protozoans
which organisms rely on diffusive transport of essential compounds across their plasma membrane- pinocytosis
parasitic protists
pinocytosis vesicles
pinosomes
phagocytosis
three strep: food capture, phagosome formation and digestion
organelles required for phagocytosis
cytosome, oral funnel, pharyngeal basket
two types of phagocytosis
filter feeders and gulpers
filter feeders
paramecium and vorticella
two types of gulpers
vegetarians and predators
vegetarian gulpers
Chilodonella and Pseudomicrothorax
predator gulpers
Actinophrys and Homalozoon
filter feeding
suspended particles are concentrated through the actin of flagella or cilia in areas where endocytosis can take place.
how are flagella and cilia useful during filter feeding
direct a current of water to the cell and especially in ciliated towards a filter device
what special organelles allow ‘gulper’ protists to obtain food
extrusomes