Questions and Answers
Are protists prokaryotic or eukaryotic?
eukaryotic
How were protists biologically classified?
Traditionally divided into plant-like and animal-like forms.
How are protists classified today?
As a diverse assemblage of plant-, animal-, and fungus-like groups.
What are some of the important functions that protists perform to contribute to human life?
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Why are protists so important to evolutionary biologists?
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Describe the endosymbiont theory.
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What are algae?
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List some of the basic characteristics of the different types of algae.
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Describe the euglenoids in terms of structure and function.
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Are euglenoids heterotrophs or autotrophs?
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Why are dinoflagellates known as whirling cells?
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Describe red tide and the connection to the dinoflagellates.
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Compare and contrast the golden algae, diatoms, and brown algae.
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Study Notes
Protists Overview
- Protists are eukaryotic organisms, distinguishing them from prokaryotic bacteria.
- They can be unicellular or multicellular and do not have highly specialized tissues.
Classification of Protists
- Traditional classification split protists into plant-like and animal-like groups.
- Current classification recognizes protists as a diverse array that includes plant-, animal-, and fungus-like organisms.
Importance of Protists
- Protists contribute to human life through various applications in medicine, including treatments for high blood pressure, digestive issues, ulcers, and arthritis.
- They play significant roles in scientific research and industrial applications.
Evolutionary Significance
- Protists are crucial for evolutionary biology, particularly the endosymbiosis theory, which explains how eukaryotic cells evolved with chloroplasts and mitochondria.
Endosymbiont Theory
- This theory posits that a large host cell and ingested bacteria formed a symbiotic relationship, leading to mutual dependence.
- Over time, mitochondria and chloroplasts became specialized and could no longer survive independently.
Algae Characteristics
- Algae are simple, non-flowering plants including seaweeds and unicellular forms.
- They contain chlorophyll and perform photosynthesis but lack true roots, stems, and leaves.
Types of Algae
- Eukaryotic organisms, algae do not have roots, stems, or leaves but possess chlorophyll for photosynthesis.
- Unicellular algae primarily exist in water environments, especially planktonic forms.
Euglenoids Structure and Function
- Euglena are mixotrophic protists capable of both photosynthesis (autotrophic) and ingestion of food (heterotrophic).
- They utilize chloroplasts for photosynthesis and exhibit locomotion through flagella and a flexible pellicle membrane.
Euglenoid Nutrition
- Euglenoids can be considered heterotrophs since they consume food but also possess the ability to photosynthesize, thanks to chloroplasts.
Dinoflagellates
- The term "dinoflagellate" signifies "whirling flagella," reflecting their motility.
- Known for significant population blooms, which can lead to phenomena like red tides.
Red Tide Phenomenon
- Red tides occur when dinoflagellate populations grow excessively, discolored due to high concentrations of cells.
- Environmental conditions driving these blooms remain only partially understood, but can reach densities of 20 million cells per liter.
Comparing Algae Types
- Diatoms are yellow or golden-brown algae, known as "Jewels of the Sea," recognized for their intricate and beautiful cell walls.
- Brown algae and golden algae also exhibit photosynthetic capabilities, with distinct characteristics differentiating them from diatoms.
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Description
Test your knowledge on the kingdom Protista with these flashcards. The quiz covers definitions, classification, and characteristics of protists, including their eukaryotic nature. Perfect for revising the key concepts from Chapter 18.