Heterotrophic Protists

How do you define protists?

Eukaryote that isn't a plant, animal, or fungi.

What are the five supergroups protists are in?

Excavata, SAR, Archaeplastida, Amoebozoa, and Opisthokonta

What feature(s) unite members of supergroup Excavata?

Cytoskeletal features, DNA sequences, groove along cell surface.

What three organisms are included in the supergroup Excavata?

Diplomonads, parabasalids, euglenozoans

What is the key feature of diplomonads?

2 haploid nuclei

What is the key feature of parabasalids?

Undulating membrane

What is the key feature of euglenozoans?

Pellicle (protein strips)

What makes kinetoplastids, a group of euglenozoans, unique?

Single mitochondrion that contains most complex mitochondrial DNA (kinteoplast)

Species from genus Trypanosoma cause disease in humans. What are examples of this?

Human african trypanosomiasis (sleeping sickness): acute or chronic; American trypanosomiasis (Chagas disease): chronic

Why are Trypanosoma hard to control?

Able to adapt rapidly (i.e. change glycoprotein coat on surface of cells)

What feature(s) unite members of Alveolata (part of supergroup SAR)?

Flattened vesicles, alveoli

What groups make up group Alveolata?

Dinoflagellates, apicomplexans, ciliates

What is a red tide?

When dinoflagellate populations bloom rapidly and release dinotoxins harmful to marine life

Why are red tides biologically significant?

Biomagnification: more and more toxin ingested as you go up the food chain

What feature(s) unite members of Apicomplexa (part of the Alveolata)?

Spore-forming parasites of animals. Have an apical complex, which is an arrangement of organelles that enables a parasite to invade a host.

What are examples of apicomplexans?

Plasmodium and toxoplasma

What disease does Plasmodium cause?

Malaria

During its life cycle, what hosts does Plasmodium require?

Asexual reproduction: humans; sexual reproduction: mosquitoes

What is a definitive host?

Organism where parasite can reproduce sexually

What is the definitive host in Toxoplasma?

Cat

What is an intermediate host?

Parasite can live inside host, but does not reach sexual maturity

What is the intermediate host in Toxoplasma?

Rats

What is an end-stage intermediate host?

Larval stage of the parasite remains trapped in tissue and cannot complete life cycle

What is the end-stage intermediate host in Toxoplasma?

Humans

What feature(s) unite members of Ciliata (the ciliates, part of the Alveolata)?

Mostly free-living. Move with cilia. Have a pellicle.

How many nuclei do ciliates have?

Two - micronuclei and macronuclei

What is the role of the micronuclei?

Only for sexual reproduction

What is the function of the macronucleus?

DNA used for a daily function

What are the two types of vacuoles in ciliates?

Food vacuoles and contractile vacuoles (regulate water balance)

What is the sexual reproduction process in ciliates?

Conjugation

What happens during conjugation?

Two cells attach, trade micronuclei.

What unites members of ameboid organisms?

Move with pseudopodia

What are the two supergroups of ameboid organisms?

Rhizaria and Amoebozoa

What do some ameboid organisms have around their cell?

Test (shell) made of silica

What two groups of organisms have tests?

Radiolarians and foraminiferans

Why is it important that tests can fossilize?

Have very long, detailed fossil records.

What are characteristics of a plasmodial slime mold?

Nonwalled, multinucleate mass of cytoplasm; feeding phase (ingest bacteria and other organic material); if food is scarce, produce sporangia and spores

What are characteristics of cellular slime molds?

Behave as separate amoebas, move through soil, feeding on bacteria; If food is scarce, organisms aggregate into a "slug", which can produce spores

Why are cellular slime molds biologically important?

Have simple development, important to the study of cell differentiation

What is the evolutionary significance of the choanoflagellates in the supergroup Opisthokonta?

Closest relatives of animals

What type of cellularity can choanoflagellates have?

Unicellular or colonial

What does a choanoflagellate look like?

Single flagellum surrounded by a funnel-like collar (sponges look very similar).