Protist Quiz

Dinoflagellates

("whirling flagellates") are mostly marine single-celled alveolate protists. Some are predators or parasites; others are photosynthetic members of the plankton or symbionts in corals. Blooms of certain species cause "red tides" that can sicken humans and kill aquatic organisms. Some of these toxins kill directly

Flagella

A long threadlike appendage

The Alveolates

Ciliated protozoans, dinoflagellates, and apicomplexans are single-celled photoautotrophs, predators, and parasites. Their shared trait is a unique layer of sacs under the plasma membrane

Stramenopiles

Colorless filamentous molds, photosynthetic single cells, and large seaweeds belong to the stramenopile lineage. Most are photosynthetic, with a brown accessory pigment (fucoxanthin) • Major components of phytoplankton

Cilia

Hair like projections that extend from surface of the cell

Cyclic AMP

In the cellular slime mold Dictyostelium, the nucleotide cyclic AMP is the signal that induces solitary amoeboid cells to stream together • Triggers gene expression which causes cells to differentiate into components of a stalk or spores. Also functions in signaling pathways of multicelled organisms

Single-celled

Most protists are __________________, but some are colonial or multicelled

autotrophs or heterotrophs

Protists can be _______________________, and a few can switch between modes

Chloroplasts

Red and green algae share a common ancestor with ___________ derived from cyanobacteria. Red algae and green algae are photosynthetic single cells and multicelled seaweeds.

Dormant Cyst

Some single-celled protists can develop into a nonmotile, _______________ during hard times

Pseodopod

Temporary Projection of the cytoplasm

Slug

When food runs out, thousands of cells form a "_____" that migrates, forms a fruiting body, and produces spores and new diploid amoeboid cells • Example: Dictyostelium discoideum

Most and some

________ ciliates are free-living predators that hunt bacteria, other protists, and one another in freshwater habitats and the oceans. Example: Paramecium ________ ciliates are parasites of animals • Balantidium coli is a parasite of humans

Amoebozoans

amoebas and slime molds

Slime molds

are "social amoebas" • Plasmodial and cellular slime molds

Protists

are eukaryotic organisms that are not fungi, plants, or animals. based on gene sequences, were grouped into many lineages of mostly single celled eukaryotes. no single trait is unique to them other than the presence of the nuclear envelop.

Euglenoids

are flagellated protists related to kinetoplastids that do not infect humans • Most prey on bacteria • Some have chloroplasts that evolved from green algae and can detect light with an eyespot • Most live in freshwater and have contractile vacuoles that expel excess water

Kinetoplastids

are flagellated protozoans with a single large mitochondrion

Radiolarians

are heterotrophic protists with silica (glassy) shells beneath their plasma membrane, most are part of the marine plankton - vacuoles filled with air keep them afloat. single celled and cytoplasm extends through many pores

Ciliates

are heterotrophic single cells that move about with the help of cilia, reproduce asexually by binary fission or sexually by conjugation

Red algae

are mostly multicelled marine algae that live in clear, warm waters. Red accessory pigments (phycobilins) allows them to live at greater depths than other algae. Life cycles vary and are often complex, with both asexual and sexual phases; there is no flagellated stage

Brown algae

are multicelled protists that live in temperate or cool seas; ranging from microscopic filaments to giant kelp. Some are used commercially: Thickeners (algins), food, fertilizer, herbal supplements (bladderwrack)

Apicomplexans

are parasitic alveolates that spend part of their life inside host cells. infect a variety of animals from worms to insects to humans where the lifecycle may involve more than one species

Green Algae

are photosynthetic single-celled and multicelled protists. Like land plants, they have cellulose in their cell walls, store sugars as starch, and have chloroplasts descended from cyanobacteria. Most are chlorophytes Chlorella: Single celled, grown as health food • Chlamydomonas: Single celled, freshwater alga • Volvox: Colonial, freshwater alga • Cladophora: Forms long filaments • Ulva: "Sea lettuce" • Codium fragilis: Branching marine alga

Foraminiferans

are single celled protists that make calcium carbonate shells from CO2, heterotrophic single celled and cytoplasm extends through many pores • Helps stabilize atmospheric CO2 levels and buffers pH of seawater • Shells accumulate as chalk or limestone Most live on the seafloor; others drift as part of the plankton

Diatoms

are single-celled or colonial protists that have a two-part silica shell • Shells accumulate on the seafloor (diatomaceousearth)

Flagellated protozoans

are single-celled protists covered by a pellicle. They swim in lakes, seas, and the body fluids of animals. They are typically heterotrophic and reproduce asexually by binary fission. Includes single-celled predators and some human parasites

Diatoms and Brown Algae

are stramenopiles, most of which are photoautotrophs

Plasmodium

causes malaria

Toxoplasma gondii

causes toxoplasmosis

Green Algae

chlorophyte algae, charophyte algae, and land plants

Alveolates

ciliates, dinoflagellates, apicomplexans

Flagellated Protozoans

euglenoids, diplomonads, parabasalids, and trypanosomes

Water molds or oomycotes

form a mesh of filaments made up of diploid cells with cellulose cell walls. They decompose organic matter in aquatic habitats, are aquatic parasites (Saprolegnia), or infect plants. include economically and ecologically important plant pathogens that infect a wide variety of crop plants, as well as forest trees • Phytopthora infestans ruined Irish potato crops • Phytopthora ramorum recently infected North American Forests

Sargassum

forms large floating mats • Important Atlantic habitat (Sargasso Sea)

Alternation of generations

haploid and diploid multicelled forms

Diplomonads and parabasalids

have multiple flagella and live in oxygen-poor waters (anaerobic flagellates) • Hydrogenosomes produce ATP anaerobically Some infect humans and cause disease • Giardia lamblia is an intestinal parasite • Trichomonas vaginalis causes a sexually transmitteddisease

Trypanosomes

include human pathogens that are transmitted by insects examples: • African sleeping sickness (T. brucei) is spread by tsetse flies • Chagas disease (T. cruzi) is spread by bloodsucking bugs

Chlorophyte Algae

include several lineages that form a clade with land plants • Desmids: A single-celled, freshwater group • Spirogyra: Forms long filaments • Stoneworts (Chara): Closely related to land plants

Giant kelp or Macrocystis

is the largest protist • Life cycle: alternation of generation with multicellular haploid and diploid bodies and a dominant sporophyte generation • Ecologically important kelp forests (Pacific)

Amoebas

live as single cells • Example: Amoeba proteus, a freshwater predator

Diploid-dominated life cycle

only gametes are haploid

Pellicle

proteins that help cells retain shape

Amoebozoans

send out pseudopods, move about, and capture food. Most have no cell walls, shell, or pellicles. They are the closest living protistan relatives of fungi and animals

Plasmodial slime molds

spend most of their lives as a plasmodium • A streaming multinucleated mass that feeds on microbes and organic matter • Undergoes mitosis many times without cell division • Develops into spore-bearing fruiting bodies

Cellular slime molds

spend most of their lives as individual amoeboid cells that feed on bacteria and reproduce by mitosis

Stramenopiles

water molds, diatoms, brown algae

Haploid-dominated life cycle

zygote is the only diploid cell