Viruses are obligate parasites

Some viruses can incorporate their genome into a host's genome

Viruses direct anabolic pathways of host cells

Viruses are not composed of cells

Gram-positive cocci in clusters that cause skin infections

Unicellular, moves by cilia, causes intestinal infections

Thrives in very salty environments, lacks peptidoglycan, produces methane

Multicellular filaments with chitin cell walls, causes athlete’s foot

Staphylococcus and Escherichia coli

Halobacterium and Staphylococcus

Cyanobacteria and Green algae

Halobacterium and Sulfolobus

A taxon composed of one or more species and a classification level lying below family

A taxon composed of classes

A taxon composed of families

A taxon belonging to a species

Plasmodium falciparum – uses flagella for motility

Amoeba – uses an apical complex to penetrate cells

Balantidium coli – uses cilia for movement

Trichomonas vaginalis – uses pseudopodia to engulf host cells

Plasmodium falciparum

Green algae

Trichomonas vaginalis

Blue-green algae

They evolved from bacteria

Some are thermoacidophiles; others are extreme halophiles

They are prokaryotes

They lack peptidoglycan in their cell walls

Eukaryotic cells with membrane-bound organelles

Prokaryotic cells that lack peptidoglycan in their cell walls

Prokaryotic cells with peptidoglycan in their cell walls

Cells with a true nucleus and linear chromosomes