BIOL 108: Eukaryotes and Protists Comprehensive Review

Comprehensive vocabulary flashcards covering eukaryotic cellular foundations, endosymbiosis, metabolic strategies, life cycles, and key taxonomic supergroups.

LECA

Last eukaryotic common ancestor; the inferred most recent common ancestral organism shared by all living eukaryotes.

Synapomorphy

A shared derived character inherited from a common ancestor that distinguishes a clade from other organisms.

Monophyletic Group

An evolutionary lineage comprising an ancestor and all of its descendants.

Endomembrane System

A functionally connected internal membrane network in eukaryotic cells that includes the nuclear envelope, endoplasmic reticulum (ER), and Golgi apparatus.

Primary Endosymbiosis

An endosymbiotic event in which a eukaryotic host cell engulfs and integrates a prokaryotic organism, such as an aerobic proteobacterium or a cyanobacterium.

Secondary Endosymbiosis

An endosymbiotic event in which a eukaryotic host engulfs and integrates a photosynthetic eukaryotic cell that already possesses a plastid, such as a red alga.

Photosynthesis (Balanced Summary)

The anabolic energy-conversion process defined by the overall balanced equation: $6\text{CO}_2 + 6\text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$.

Cellular Respiration (Balanced Summary)

The catabolic pathway releasing usable energy from organic molecules, summarized as: $\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{ATP} + \text{heat}$.

Photoautotrophy

A nutritional mode in which organisms derive energy from light and obtain their carbon from carbon dioxide ($\text{CO}_2$).

Chemoheterotrophy

A nutritional mode in which organisms obtain both chemical energy and organic carbon directly from organic substances.

Mixotrophy

A flexible nutritional strategy combining photosynthetic autotrophy and heterotrophy depending on environmental conditions, as observed in some Euglena species.

Phagocytosis

The heterotrophic cellular ingestion of relatively large food particles via membrane invagination, forming a food vacuole for intracellular digestion.

Pinocytosis

The uptake of extracellular fluid and dissolved solutes into the cell via small endocytic vesicles.

Absorption

The direct transport and uptake of dissolved nutrient molecules across the cellular plasma membrane.

Contractile Vacuole

An osmoregulatory organelle found in freshwater protists that collects and expels excess water to prevent cell swelling in hypotonic environments.

Plankton

Aquatic organisms that drift or are carried primarily by water currents, encompassing both photosynthetic phytoplankton and heterotrophic zooplankton.

Alternation of Generations

A life cycle featuring alternating multicellular haploid ($n$) gametophyte and multicellular diploid ($2n$) sporophyte phases, as seen in brown algae.

Conjugation (Ciliates)

A sexual process wherein compatible ciliate partners exchange haploid micronuclei to generate genetic variation without immediately increasing the population cell count.

Micronucleus

The small, germline nucleus in ciliates that contains hereditary genetic material and participates in sexual exchange during conjugation.

Macronucleus

The somatic nucleus in ciliates that regulates ordinary daily cellular metabolism and gene expression.

Alveoli

Small membrane-bound sacs situated directly beneath the plasma membrane in Alveolata that stabilize the surface and may assist in osmoregulation.

Dinoflagellates

Alveolates characterized by cellulose plates and two flagella producing a distinct spinning locomotion; includes coral mutualists, phytoplankton, and red-tide toxin producers.

Foraminiferans

Rhizarians that produce porous shells, generally composed of calcium carbonate, through which thin, filamentous pseudopodia extend.

Radiolarians

Rhizarians characterized by delicate internal skeletons, generally fabricated from silica, and radiating threadlike pseudopodia (axopodia).

Discoba

A eukaryotic clade characterized by a spiral or crystalline rod inside their flagella; includes photosynthetic euglenids and parasitic kinetoplastids.

Kinetoplast

A dense, organized concentration of mitochondrial DNA residing within a single large mitochondrion, characteristic of kinetoplastids like Trypanosoma.

Metamonada

A group of typically anaerobic protists with secondary reduction of mitochondria into modified derivatives like mitosomes and hydrogenosomes; includes Giardia and Trichomonas.

Mitosomes

Reduced, non-aerobic mitochondrion-related organelle relics found in diplomonads such as Giardia intestinalis.

Hydrogenosomes

Modified mitochondrion-related anaerobic organelles found in parabasalids such as Trichomonas vaginalis that produce molecular hydrogen.

Opisthokonta

A eukaryotic supergroup that includes choanoflagellates, animals, and fungi, characterized by motile stages propelled by a single posterior flagellum.

Plasmodium (Slime Mould)

A large, multinucleate diploid ($2n$) cellular feeding mass formed after fertilization in plasmodial slime moulds such as Physarum.

Archaeplastida

The eukaryotic supergroup comprising red algae, green algae, and land plants, united by ancestral primary endosymbiosis of a photosynthetic cyanobacterium.

Phycobilins

Water-soluble accessory pigments present in red algae that can mask chlorophyll and assist in capturing light in marine environments.

Stramenopiles

A major eukaryotic supergroup characterized by cells possessing a distinctive hairy straw-like flagellum paired with a smooth flagellum.

Diatoms

Unicellular, photosynthetic Stramenopiles bearing two-part glassy silica shells and plastids surrounded by four membranes, which store energy as lipids or oils.

Oomycetes

Chemoheterotrophic, fungus-like Stramenopiles possessing cell walls made of cellulose that have secondarily lost photosynthetic plastids.