Groups of Microorganisms

Bacteria and Archaea

Smallest cells on Earth and found everywhere there is water. Reproduce asexually, and contain a cell wall that protects them from water pressure.

Classified as prokaryotes

Bacteria

Most are freely living but some will live in organisms. Very small portion of these are truly pathogenic and will cause disease

Has peptidoglycan in cell wall

Archaea

Found living in very extreme environments and do not infect or cause disease in humans

Does not have peptidoglycan in cell wall

Saprobes

Fungi are this, means that they break down decaying or dead organisms for nutrients

Fungus

These are not photosynthetic or move but are classified as eukaryotes, have a nucleus and organelles surrounded by membranes. Has a cell wall that is chemically different from other microorganisms

Some can be pathogenic

Yeasts

Unicellular fungus, generally reproduce asexually by budding

Molds

Multicellular fungus, grow as long filaments called hyphae. Can reproduce asexually or sexually

Protozoa

Unicellular eukaryotes that are similar to animals in terms of nutrient needs and cell structure. Most do not infect humans or cause disease, all live in water. Classified based on how they move with either pseudopods, cilia, or flagella

Algae

Unicellular or multicellular eukaryotes which are photosynthetic and are classified based on pigmentation and cell wall structure. Very simple reproductive structures compared to plants