Ch 20 The Protists

protist

eukaryote that is not a fungus, animal, or plant

flagellated protozoan

protist belonging to an entirely or mostly heterotrophic lineage with no cell wall and one or more flagella

plasmodial slime mold

protist that feeds as a multinucleated mass; forms a spore-bearing structure when environmental conditions become unfavorable

water mold

protist that grows as nutrient-absorbing filaments

sporophyte

spore-forming diploid body that forms in the life cycle of land plants and some protists

what are protists?

-a collection of eukaryotic lineages. most are single-celled but there are some multi-celled species -some are autotrophs, others are heterotrophs, some can switch between modes -most reproduce sexually and asexually

what are amoebozoans?

-heterotrophic protists with cells that lack a cell with wall or pellicle, and so can constantly change shape -amoebas live as single cells, usually in fresh water -slime molds live on forest floors, plasmodial slime molds feed as a big multinucleated mass. cellular slime molds feed as single cells, but come together as a multi-celled mass when conditions are unfavorable. both types of slime molds form fruiting bodies that release spores

what are stramenopiles?

-include diverse lineages that are united on the basis of their genetic similarity rather than any visible traits -water molds are filamentous decomposers and parasites -diatoms are silica-shelled cells, brown algae are multi-cellular. Both groups have a brown accessory pigment in chloroplasts that evolved from a red alga

what are flagellated protozoans?

-parabasalids and diplomonads are heterotrophs that lack mitochondria, some are important human pathogens -trypanosomes are parasites with a large mitochondrion, biting insects transmit some that cause human disease -euglenoids include heterotrophs and photoautotrophs with chloroplasts that evolved from green algae

what are red algae and green algae?

-red and green algae are protists that belong to the same clade as the land plants. all members of this clade deposit cellulose in their cell wall and store excess sugars as starch -red algae mostly multicellular and marine, have red accessory pigments that allow them to live at greater depths than other algae -green algae include single-celled, colonial, and multi-celled species. one subgroup, the charophyte algae, includes closest living relatives of land plants

what are alveolates?

-single cells with an array of membrane-bound sacs (alveoli) beneath the plasma membrane -Dinoflagellates are common in plankton, flagellated heterotrophs of photoautotrophs have cellulose plates and move with a whirling motion -the ciliates are heterotrophs. cilia cover all or part of the cell surface and function in locomotion and feeding -apicomplexans are intracellular parasites with a special host-piercing device

cellular slime mold

amoeba-like protist that feeds as a single predatory cell; joins with others to form a multicellular spore-bearing structure when conditions are unfavorable

toxin

chemical that is made by one organism and harms another

euglenoid

flagellated protozoan with multiple mitochondria; may be heterophic or have chloroplast descended from algae

gametophyte

gamete-producing haploid body that forms in the life cycle of land plants and some protists

contractile vacuole

in freshwater protists, an organelle that collects and expels excess water

pellicle

layer of proteins that gives shape to many unwalled, single-celled protists

alveolate

member of protist lineage having small sacs beneath the plasma membrane; dinoflagellate, ciliate, or apicomplexan.

brown alga

multi-celled marine protist with a brown accessory pigment in its chloroplasts

alternation of generations

of land plants and some protists, a life cycle in which haploid and diploid multi-celled bodies form

trypanosome

parasitic flagellate with a single mitochondrion and a membrane-encased flagellum

green alga

photosynthetic protist that deposits cellulose in its cell wall, stores sugars as starch, and has chloroplast containing chlorophylls a and b

red alga

photosynthetic protist that deposits cellulose in its cell wall, stores sugars as starch, and has chloroplast containing chlorophylls a and red pigments called phycobilins

algal bloom

population explosion of tiny aquatic producers

amoebozoan

shape-shifting heterotrophic protist with no pellicle or cell wall; and amoeba or slime mold

dinoflagellate

single-celled aquatic protist with cellulose plates and two flagella; may be heterotrophic or photosynthetic

diatom

single-celled photosynthetic protist with brown accessory pigments in its chloroplasts and a two-part silica shell

amoeba

single-celled protist that extends pseudopods to move and to capture prey

apicomplexan

single-celled protist that lives as a parasite inside animal cells

ciliate

single-celled, heterotrophic protist with many cilia