Overview of Protists, Fungi, and Bacterial Classification

Euglena

Excavata supergroup; Unicellular; Mixotroph; Moves via flagella; Has green chloroplasts, red eyespot (stigma), and pellicle

Trypanosoma

Excavata supergroup; Unicellular; Heterotroph; Moves via flagella; Causes sleeping sickness, transmitted by tsetse fly, has undulating membrane

Paramecium

Chromalveolata supergroup; Unicellular; Heterotroph; Moves via cilia; Has oral groove for feeding, contractile vacuoles, two nuclei (macro and micro)

Diatom

Chromalveolata supergroup; Unicellular; Autotroph; Non-motile (some can glide); Has silicon dioxide cell wall (frustule), glass-like appearance, important phytoplankton

Foraminifera

Rhizaria supergroup; Unicellular; Heterotroph; Moves via pseudopodia (reticulopodia); Has calcium carbonate shells (tests), marine organisms, important in fossil record

Chondrus

Archaeplastid supergroup; Multicellular; Autotroph; Non-motile; Red algae, source of carrageenan, flattened branching thallus

Volvox

Archaeplastid supergroup; Colonial; Autotroph; Moves via flagella; Hollow sphere of cells, shows division of labor between somatic and reproductive cells

Amoeba

Unikont supergroup; Unicellular; Heterotroph; Moves via pseudopodia (lobopodia); Amorphous shape, engulfs food by phagocytosis

Excavata

Protist supergroup including Euglena and Trypanosoma; characterized by asymmetrical cells, often with flagella, many with modified mitochondria

Chromalveolata

Protist supergroup including Paramecium and Diatoms; includes alveolates with membrane sacs under cell surface and stramenopiles

Rhizaria

Protist supergroup including Foraminifera; characterized by threadlike pseudopodia, many with shells or tests

Archaeplastida

Protist supergroup including Chondrus and Volvox; includes all photosynthetic organisms with primary plastids derived from cyanobacteria

Unikonta

Protist supergroup including Amoeba; characterized by single flagellum when present; includes animals and fungi as well

Chytridiomycota (Allomyces)

Fungal phylum with gametophyte (haploid phase that produces gametes) and sporophyte (diploid phase that produces spores); only fungi with motile spores (zoospores), aquatic, flagellated

Zygomycota (Rhizopus)

Fungal phylum with sporangium (produces asexual spores) and gametangia (fuse during sexual reproduction); fast-growing mold, coenocytic hyphae (no septa), black bread mold

Ascomycota (Peziza)

Fungal phylum with asci (sac-like structures containing ascospores) and ascospores (sexual spores); cup-shaped fruiting bodies, includes yeast, most lichens, penicillin

Basidiomycota (Coprinus)

Fungal phylum with basidium (club-shaped structure producing basidiospores) and basidiospores (sexual spores); includes mushrooms, bracket fungi, rusts, smuts, septate hyphae

Gram Positive Bacteria

Thick peptidoglycan layer; retain crystal violet dye (purple); no outer membrane; teichoic acids present; examples: Staphylococcus, Streptococcus; more susceptible to penicillin, vancomycin

Gram Negative Bacteria

Thin peptidoglycan layer with outer membrane; appear pink/red with counterstain; outer membrane contains lipopolysaccharides; no teichoic acids; examples: E. coli, Salmonella; resistant to many antibiotics due to outer membrane barrier

Why do some antibiotics work on Gram positive but not Gram negative bacteria?

Gram-negative bacteria have an outer membrane barrier that prevents many antibiotics from reaching targets; some antibiotics are too large to pass through porins in the outer membrane; antibiotics like penicillin target cell wall synthesis, which is more accessible in Gram-positive bacteria