LT More Protists Flashcards
What defines the group “protists”?
Eukaryotic organisms not classified as animals, plants, or fungi.
Often unicellular, but some are simple multicellular or colonial organisms.
Highly diverse in structure, nutrition, and locomotion.
What are the three major modes of nutrition in protists?
Photosynthesis: Photoautotrophs (e.g., algae, diatoms).
Absorptive feeding: Chemoheterotrophs absorb organic material.
Ingestive feeding: Use structures (e.g., pseudopodia, cilia) to engulf or sweep food into the cell.
What are the primary methods of locomotion in protists?
Amoeboid motion using pseudopodia (e.g., Amoeba).
Swimming with flagella (e.g., Euglena).
Swimming with cilia (e.g., Paramecium).
How are protists ecologically important?
Primary producers: Photoautotrophs (e.g., diatoms) form the base of aquatic food chains.
Secondary consumers: Chemoheterotrophs feed on producers and detritus.
Mutualists: Help in digestion (e.g., protozoa in termites).
Parasites: Cause diseases (e.g., Trypanosoma in humans).
Decomposers: Recycle nutrients from dead organic material.
What are key features of desmids?
Green algae, unicellular, with two symmetric semi-cells.
Found in freshwater ecosystems.
Photosynthetic with chlorophyll a and b.
Store energy as starch.
What are key features of diatoms?
Colonial green algae in freshwater.
Contains somatic cells (photosynthesis and locomotion) and reproductive cells.
Stores excess glucose as starch.
Lacks complex cellulose in cell walls, uses extracellular glycoprotein matrix.
What distinguishes Euglena?
Mixotrophic: Can photosynthesize or feed heterotrophically.
Contains chlorophyll a and b, red eyespot for phototaxis.
Has a flexible pellicle instead of a rigid cell wall.
What are characteristics of Paramecium and Stentor?
Both are ciliates with coordinated cilia movement for feeding and locomotion.
Paramecium: Intracellular digestion via food vacuoles; has macronucleus (metabolism) and micronucleus (reproduction).
Stentor: Large trumpet-shaped body, uses cilia to create feeding currents.
How does Amoeba move and feed?
Moves with pseudopodia by cytoplasmic streaming.
Engulfs prey (e.g., bacteria, other protists) into food vacuoles for intracellular digestion.
What ecological roles do diatoms play?
Primary producers in aquatic ecosystems.
Contribute to phytoplankton and oxygen production.
Dead diatoms contribute to fossil fuels and diatomaceous earth.
What do protozoa contribute to termite digestion?
Mutualistic protozoa digest cellulose in wood, producing nutrients for termites.
How are zooxanthellae important in corals?
Provide sugars through photosynthesis, supporting coral energy needs.
Corals offer a safe, stable environment for zooxanthellae.
How is red algae used in bacterial culture?
Agar, a product of red algae, is used as a growth medium in bacterial labs.
What are economic uses of diatomaceous earth?
Filtering applications, polishing agents, abrasive materials (e.g., toothpaste).
Contains fossilized diatom shells made of silica.
What causes African sleeping sickness?
Pathogen: Trypanosoma brucei gambiense.
Vector: Tsetse fly.
Symptoms: Fever, fatigue, insomnia, neurological damage in later stages.
