Biology Chapter 18: Protists Flashcards

Protists Overview

• Eukaryotes are organisms with one or more cells, featuring a nucleus and membrane-bound organelles.
• Protists are eukaryotic organisms distinct from plants, fungi, or animals.

Importance of Protists

• Serve as the base of many aquatic food webs.
• Act as parasites, causing diseases in plants and animals, including humans.
• Assist in locating oil reserves.
• Used in various applications, such as in reflective paints and making chocolate smooth.

Evolutionary Significance

• Studying protists helps trace the evolutionary history of eukaryotic structures, such as mitochondria and chloroplasts, and the development of multicellularity.

Types of Algae

• Algae are aquatic, photosynthetic protists contributing to aquatic ecosystems.
• Euglenoids are unicellular and flagellated with elongated cells.
• Dinoflagellates have two unequal flagella and often possess cellulose plates.
• Golden algae have yellowish pigments and two flagella.
• Diatoms feature silica cell walls with ornate designs.
• Brown algae are multicellular with swimming spores and brown pigments.
• Red algae are marine and contain red or bluish pigments.
• Green algae resemble land plants in starch, pigments, and cell wall structure.

Nutrition and Classification of Algae

• Most algae are photosynthetic, although some exhibit heterotrophic behavior.
• Algal classification criteria include:
  • Types of photosynthetic pigments.
  • Composition of the cell wall.
  • Storage carbohydrates.
  • Number of flagella.
  • Cellular organization (unicellular, colonial, or multicellular).

Characteristics of Major Algal Groups

• Euglenoids: Unicellular flagellates.
• Dinoflagellates: Marine with cellulose plates and two flagella.
• Golden algae: Yellowish pigments.
• Diatoms: Silica shells with complex forms.
• Brown algae: Marine with intricate body structures.
• Red algae: Marine with unique pigments.
• Green algae: Contain chlorophylls, starch, and cellulose, exhibiting alternation of generations.

Slime Molds

• Plasmodial slime molds are massive cells with multiple nuclei during their feeding stage.
• Cellular slime molds consist of individual cells that form a multicellular structure during food scarcity.
• Both types are heterotrophic and produce spores when food is limited.

Water Molds

• Water molds, or oomycetes, are filamentous and heterotrophic with swimming spores.
• Known for their ecological roles as decomposers and plant/animal parasites, historically notable for causing the Irish potato famine and impacting the French wine industry.

Protozoa

• Protozoa are unicellular protists that are heterotrophic and motile, often characterized by flagella for movement.

Flagellated Protozoans

• Flagellated protozoans are unicellular and possess one or more flagella, aiding in mobility and feeding.

These flashcards cover key terms and definitions related to protists, as outlined in Chapter 18 of your biology textbook. Study essential concepts such as eukaryotes, protists, and the endosymbiont theory to enhance your understanding of this crucial biological group.