Bio Ch 21 Flashcards
Protists
simplest but most diverse of the eukaryotes
Endosymbiosis
process by which eukaryotic cells acquired mitochondria and plastids, including chloroplasts, by engulfing a free-living bacterium that developed a symbiotic relationship within the host cell
Mixotrophic
able to combine autotrophic and heterotrophic nutritional modes (some protozoans)
Cysts
protists can form spores or these that are dormant phases of the life cycle that can survive until favorable conditions return
Plankton
organisms that are suspended in the water and serve as food for heterotrophic protists and animals
Monophyletic
not all belonging to the same evolutionary lineage
Supergroup
high-level taxonomic group below domain and above kingdom; each one represents a separate evolutionary lineage
Archaeplastids
supergroup including land plants and other photosynthetic organisms such as green and red algae that have plastids derived from endosymbiotic cyanobacteria
Green Algae
protists that contain both chlorophylls a & b; inhabit a variety of environments, including oceans, fresh water, snowbanks, the bark of trees, and the backs of turtles; 17000 species
Chlorophytes
Subgroup of green algae; ex = chlamydomonas (tiny, photoautotrophic, inhabits still freshwater pools)
Charophytes
Subgroup of green algae most closely related to land plants; filamentous algae
Zoospores
haploid flagellated spores that grow to become adult vegetative cells, thus completing the life cycle
Colony
loose association of independent cells; ex Volvox
Filaments
end-to-end chains of cells
Conjugation
temporary union during which the cells exchange genetic material
Red Algae
multicellular seaweeds that possess red and blue accessory pigments that transfer energy from absorbed light to the photopigment chlorophyll during photosynthesis
Accessory Pigments
transfer energy from absorbed light to the photopigment chlorophyll during photosynthesis
Chromalveolates
supergroup with 2 large subgroups - the stramenopiles and the alveolates
Stramenopiles
brown algae, diatoms, golden brown algae, water molds
Brown Algae
have chlorophylls a & c in their chloroplasts and an accessory carotenoid pigment that gives them their characteristic brown color
Diatom
tiny, single-celled stramenopile with an ornate silica shell
Golden Brown Algae
derive their distinctive color from yellow-brown carotenoid accessory pigments; typically have 2 flagella with tubular hairs, a characteristic of stramenopiles
Water molds
form furry growths when they parasitize fishes or insects and decompose remains; most are saphrotrophic; AKA oomycetes
Alveolates
have alveoli (small air sacs) lying just beneath their plasma membranes that are thought to lend support to the cell surface; unicellular
Dinoflagellates
unicellular, photoautotrophic algae encased by protective cellulose and silicate plates; typically have 2 flagella; 4000 species, some bio-luminescent; ex = zooxanthellae; one of most important groups of primary producers in the marine ecosystem
Red Tides
colorful algal blooms; sometimes so extensive they can be seen from space
Ciliates
unicellular protists that move by means of cilia; most structurally complex and specialized of all protozoa; ex = paramecium; 8000 species
Trichocysts
oval capsules that lie just beneath the pellicle contain these; upon mechanical or chemical stimulation, these discharge long, barbed threads that are useful for defense and for capturing prey; some release poisons
Apicomplexans (sporozoans)
nearly 3900 species of nonmotile, parasitic, spore-forming protozoans; possess a unique organelle called an apicoplast, which is used to penetrate a host cell; ex = plasmodium (responsible for malaria)
Vector
intermediate organism that transmits a disease between the host and other organisms
Excavates
supergroup that include zooflagellates that have atypical or absent mitochondria and distinctive flagella and/or deep (excavated) oral grooves; includes euglenids, parabasalids, diplomonads, & kinetoplastids
Euglenids
small, freshwater, unicellular organisms; 1000 species; very diverse; some mixotrophic, some photoautotrophic, some heterotrophic; 1/3 have chloroplasts, rest do not; produce an unusual type of carbohydrate called paramylon
Parabasalids
have a unique, fibrous connection between the Golgi apparatus and flagella; causes most common STD, trichomoniasis
Diplomonad
cell with 2 nuclei and 2 sets of flagella
Kinetoplastids
single-celled, flagellated protozoans named for distinctive kinetoplasts, large masses of DNA found in their mitochondria; ex = trypanosomes (cause of African Sleeping Sickness; vector = tsetse fly; also causes Chagas disease)
Amoebazoans
Supergroup of protozoans that move by pseudopods
Pseudopods
“false foot”; form when an amoebazoan’s microfilaments contract and extend as the cytoplasm streams toward a particular direction
Amoeboids
protists that move and ingest their food with pseudopods; hundreds of species identified
Phagocytosis
amoeboids feed this way; engulf their prey with a pseudopod; digestion occurs within a food vacuole
Plasmodial slime molds
these usually exists as a plasmodium, a diploid, multinucleated, cytoplasmic mass enveloped by a slime sheath (not the same as the genus plasmodium from the alveolate group); 700 species
Sporangium (plural sporangia)
reproductive structure that produces spores; aggregate of these = fruiting body
Cellular slime molds
exist as individual amoeboid cells; common in soil; feed on bacteria and yeasts; 70 species
Opisthokonts
Supergroup made up of animals and fungi along with some closely related protists
Choanoflagellates
opisthokont; animal-like protozoans closely related to sponges; filter feeders
Nucleariids
Opisthokonts with a rounded or slightly flattened cell body and threadlike pseudopods called filopodia
Rhiazarians
Supergroup consisting of foraminiferans and the radiolarians
Foraminiferans & Radiolarians
organisms with fine, threadlike pseudopods; have a skeleton called a test made of calcium carbonate
