Bio 1B Protists

Protists are the informal name for

unicellular eukaryotes

Protists are the most […] of any other group of eukaryotes

Structurally and functionally diverse

Characteristics of protists include

[multiple choice]

Protists’ diversity is due to

endosymbiosis

Mitochondria is a result of endosymbiosis and was engulfed by

an alpha proteobacterium

Plastids are a result of endosymbiosis and were engulfed by

a photosynthetic cyanobacterium

Plastids later evolved into

red and green algae, which respectively evolved into dinoflagellates + stramenophiles and euglenids + chlorarachniophytes

The four supergroups of protists are

Excavata, SAR (stramenophiles, alveolates, rhizarians), archaeplastida, unikonta

The main protists of the excavata supergroup are

Diplomonads, parabasalids, and euglenozoans

The main characteristics of both diplomonads and parabasalids are

A lack of plastids and modified mitochondria

Diplomonads and parabasalids primarily live in

Anaerobic environments

Euglenozoans are characterized by

A spiral or crystalline rod inside their flagella

Within the euglenozoa clade, there are two groups:

Kinetoplastids and euglenids

Do kinetoplastids include parasitic species?

Yes, examples include Trypanosoma brucei, which causes the African sleeping sickness, and Trypanosoma cruzi, which causes American trypanosomiasis

The main stramenophiles (from the SAR supergroup) are:

diatoms, golden algae, and brown algae

The main characteristic of stramenophiles is

the presence of both hairy and smooth flagella.

What is the ecological significance of golden and brown algae?

Golden and brown algae contain some of the most important photosynthetic organisms on the planet

What is the significance of diatoms?

Diatoms are a major component of phytoplankton and transport carbon dioxide from the atmosphere to the ocean floor

Do diatoms include parasitic species?

No, but some species produce biotoxins, an example is Pseudonitzchia, found in shellfish, anchovies, and sardines, and it produces domoic acid and can cause amnesiac shellfish poisoning

What is the origin of the name of golden algae?

Their yellow and brown carotenoids

What are some characteristics of brown algae?

It is the largest and most complex algae, it is multicellular, it includes what we commonly think of as seaweeds

Define alternation of generations

A variety of life cycles characterized by part of their life being diploid, usually after zygote formation and lasts a relatively short time, and the remaining majority of their life being haploid

The main protists of alveolates include

Dinoflagellates, apicomplexans, and ciliates

The main characteristic of alveolates are

Alveoli (as the name suggests), which contribute to maintaining the shape of the cell

Dinoflagellates are characterized by… and are abundant components of

cellulose plates, marine and freshwater plankton

What role do dinoflagellates have in coral reefs?

Dinoflagellates (specifically zooxanthellae) are symbionts of corals, and they maintain coral health and prevent coral bleaching

Apicomplexans are

Parasites of animals

Apicomplexans’ mode of infection involves

Using their apex, which consists of a special complex of organelles, to penetrate a host cell and their tissues, then propagating as sporozoites

Ciliates are characterized by… and have the ability to

Cilia (which they use to move and feed), genetically differentiate through conjugation

The main protists of rhizarians are

Radiolarians, foraminifera (forams), and cercozoans

The main characteristic of rhizarians is

Thread-like pseudopodia (bodily extensions used for feeding and moving)

Radiolarians are characterized by

A delicate, symmetrical internal skeleton composed of silica

The name for forams originated from… and contain…

Their porous, multichambered shells called tests (through which their pseudopodia extend), endosymbiotic algae