Protists

Protists: Eukaryotic Microorganisms

• Protists are eukaryotic microorganisms with cells containing a nucleus and membrane-bound organelles like chloroplasts and mitochondria.
• Living organisms are classified as eukaryotes (with a nucleus) or prokaryotes (without a nucleus).
• Prokaryotes, such as bacteria and cyanobacteria, lack a membrane-bound nucleus or other organelles.
• Protozoans, a type of protist, are single-celled, animal-like microorganisms found in freshwater or saltwater.
• Protozoans are heterotrophic, free-moving, and can be parasitic, consuming other organisms for energy.
• Ciliates, a group of protozoans, have cilia to hunt for prey, move quickly through water, feed, attach to other organisms, and feel sensations.
• Flagellates, another type of protozoan, have flagella and can be plant-like (autotrophs) or animal-like (heterotrophs).
• Heliozoans are freshwater, unicellular protozoans recognized by their spherical shape and silica shell, using pseudopods to capture prey.
• Amoebas are eukaryotic, single-celled protozoa that can alter their cell shape, forming pseudopods to move and capture prey through phagocytosis.
• Algae, found in the kingdom Protista, range from unicellular to giant kelp and are typically autotrophs using photosynthesis for energy.
• Euglenophytes are unicellular organisms using flagella to move, being mixotrophs that can capture energy from the sun or ingest prey.
• Diatoms, single-celled algae with a glass-like silica shell, form the base of the food chain in aquatic environments and are autotrophs using chloroplasts for energy.