Podcast
Questions and Answers
What is the primary function of the pellicle in Euglena mutabilis?
What is the primary function of the pellicle in Euglena mutabilis?
What percentage of photosynthesis is carried out by Euglena?
What percentage of photosynthesis is carried out by Euglena?
Which property does NOT describe the lipid content of Euglena?
Which property does NOT describe the lipid content of Euglena?
Under which conditions does Euglena form a protective wall and become dormant?
Under which conditions does Euglena form a protective wall and become dormant?
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What role do Euglena play in ecosystems besides photosynthesis?
What role do Euglena play in ecosystems besides photosynthesis?
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What enables Euglena to survive during periods without light?
What enables Euglena to survive during periods without light?
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What characteristic is used to identify the genus Euglena?
What characteristic is used to identify the genus Euglena?
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Which aspect of Euglena's structure helps in phototaxis?
Which aspect of Euglena's structure helps in phototaxis?
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What is the primary mode of nutrition for Euglena under sufficient sunlight?
What is the primary mode of nutrition for Euglena under sufficient sunlight?
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Which of the following best describes the chloroplasts of Euglena?
Which of the following best describes the chloroplasts of Euglena?
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Euglena can survive in environments lacking light by using which of the following methods?
Euglena can survive in environments lacking light by using which of the following methods?
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What role does the paraflagellar body play in Euglena's ability to sense light?
What role does the paraflagellar body play in Euglena's ability to sense light?
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How long do Euglena cells typically range in size?
How long do Euglena cells typically range in size?
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What distinguishes Desmokonts from Dinokonts in terms of flagellar arrangement?
What distinguishes Desmokonts from Dinokonts in terms of flagellar arrangement?
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Which of the following dinoflagellates is known for producing saxitoxins?
Which of the following dinoflagellates is known for producing saxitoxins?
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What is a characteristic feature of the dinoflagellate Prorocentrum micans?
What is a characteristic feature of the dinoflagellate Prorocentrum micans?
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What type of organelle is associated with light sensitivity in some dinoflagellates?
What type of organelle is associated with light sensitivity in some dinoflagellates?
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In which structure is the prominent nucleolus typically found in most dinoflagellates?
In which structure is the prominent nucleolus typically found in most dinoflagellates?
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What is a defining physical characteristic of Dinokonts compared to Desmokonts?
What is a defining physical characteristic of Dinokonts compared to Desmokonts?
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Which structure in dinoflagellates is analogous to the eyes of metazoans?
Which structure in dinoflagellates is analogous to the eyes of metazoans?
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What type of dinoflagellate is Akashiwo sanguinea classified as?
What type of dinoflagellate is Akashiwo sanguinea classified as?
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What allows male gametes of centric diatoms to move actively?
What allows male gametes of centric diatoms to move actively?
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Which pigment is NOT found in photosynthetic diatoms?
Which pigment is NOT found in photosynthetic diatoms?
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What is a primary human use of diatomaceous earth?
What is a primary human use of diatomaceous earth?
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What characterizes dinoflagellates compared to diatoms?
What characterizes dinoflagellates compared to diatoms?
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Which of the following is a characteristic of dinoflagellate chloroplasts?
Which of the following is a characteristic of dinoflagellate chloroplasts?
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Which statement about diatoms is incorrect?
Which statement about diatoms is incorrect?
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What type of feeding behavior do dinoflagellates exhibit?
What type of feeding behavior do dinoflagellates exhibit?
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Which of the following is NOT a product derived from diatom shells?
Which of the following is NOT a product derived from diatom shells?
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What significant role do diatoms play in the environment?
What significant role do diatoms play in the environment?
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Which of the following is a common endosymbiont pigment found in some dinoflagellates?
Which of the following is a common endosymbiont pigment found in some dinoflagellates?
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What type of life cycle do haplobiontic species exhibit?
What type of life cycle do haplobiontic species exhibit?
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Which accessory pigments are found in green algae?
Which accessory pigments are found in green algae?
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What leads to the phenomenon known as red tide?
What leads to the phenomenon known as red tide?
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What is true about the mitochondria of green algae?
What is true about the mitochondria of green algae?
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Which of the following best describes the reproduction method of oogamy?
Which of the following best describes the reproduction method of oogamy?
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What feature contributes to the green color of green algae?
What feature contributes to the green color of green algae?
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Which reproductive strategy is exhibited by green algae?
Which reproductive strategy is exhibited by green algae?
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What characteristic of green algae aids in their movement?
What characteristic of green algae aids in their movement?
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What do typical protists primarily exhibit in terms of cellular structure?
What do typical protists primarily exhibit in terms of cellular structure?
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In the alternation of generations in protists, what form is the sporophyte?
In the alternation of generations in protists, what form is the sporophyte?
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What is the type of cell division that produces haploid reproductive cells in protists?
What is the type of cell division that produces haploid reproductive cells in protists?
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Which of the following is true about the environment in which protists thrive?
Which of the following is true about the environment in which protists thrive?
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What term describes the multicellular form of protists that produces spores?
What term describes the multicellular form of protists that produces spores?
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Which statement accurately reflects the complexity of protist cell structures?
Which statement accurately reflects the complexity of protist cell structures?
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What type of gametes results from the mitotic division in haploid multicellular organisms?
What type of gametes results from the mitotic division in haploid multicellular organisms?
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What is the primary reproductive strategy for protists during adverse conditions?
What is the primary reproductive strategy for protists during adverse conditions?
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Study Notes
BGY3100: Biology of Microorganism (Protists) - Part 2
- Course: BGY3100 Biology of Microorganism
- Semester: 1, 2024/2025
- Topic: Protists (part 2)
- Speaker: Dr. Edward Entalai Besi, Department of Biology, Faculty of Science, UPM, Malaysia, IUCN Species Survival Commission (SSC) member
Content
- General characteristics of protists
- Importance of protists in the ecosystem
- Diseases and interaction with host
Topic Learning Outcomes
- List general characteristics that describe protists
- Discuss protists' importance in the ecosystem
- Explain protist diseases and interactions with hosts
Plant-like Protists (autotrophs)
- Euglena (single-celled, flagellate)
- Widely studied member with 54 genera and at least 800 species
- Found in freshwater and saltwater
- Used as a model organism
- Feed through phototrophy (like plants)
- Chloroplast with three membranes
- Contains Chlorophyll a and b (like green algae)
- Chloroplast contains pyrenoid, a structure for starch storage, allowing survival in low-light conditions
- Pyrenoid is used to identify Euglena species
- Can also take nourishment heterotrophically (like animals), absorbing nutrients through osmotrophy
- Diet includes organic matter (e.g., beef extract, peptone, acetate, ethanol)
- Euglena also has:
- A red eyespot (stigma) that filters specific wavelengths of light useful for phototaxis (moving towards light)
- Two flagella; one short, one long
- Some Euglena species lack flagella, with both flagella completely inside the cell's reservoir
- Possess a pellicle (protein layer) supported by a microtubule substructure
- Euglena mutabilis is an example
- Diatoms (unicellular, solitary cells or in colonies)
- Major group of microalgae, type of phytoplankton
- Abundant in oceans and waterways attached to benthic substrates, floating debris and macrophytes
- Range in size from 2 to 200 µm, with some larger species
- Two distinct shapes:
- Centric diatoms (radially symmetric)
- Pennate diatoms (bilaterally symmetric), often ribbons, fans, zigzags, or stars
- Cell wall (frustule) made of hydrated silicon dioxide (silica), creating a highly patterned and intricate structure
- Has structural colors due to photonic nanostructure
- Described as "jewels of the sea" and "living opals"
- Reproduce both sexually and asexually (repeated mitotic divisions)
- Crucial for biological production from the modern oceanic silicon cycle
- Movement
- Mostly passive, driven by water currents and wind
- Male gametes in centric diatoms have flagella
- Dense cell walls make some types readily sink
- Photosynthetic diatoms
- Contain chloroplasts with four membranes, similar to red algae
- Chloroplasts contain chlorophylls a and c
- Contain pigments like beta-carotene, fucoxanthin, diatoxanthin, and diadinoxanthin
Dinoflagellates
- Single-celled
- Considered algae, a major group of marine eukaryotes, but smaller than diatoms
- Mostly marine plankton but are common in freshwater & brackish habitats
- Population distribution depends on sea surface temperature, salinity, or depth
- Many are photosynthetic but largely mixotrophic
- Possess chloroplast with three membranes like other red algae
- Contain chlorophylls a and c2 and additional pigments like beta-carotene, xanthophylls
- Some have acquired other pigments through endosymbiosis, including fucoxanthin
-Two main groups:
- Desmokonts (uneven flagella)
- Dinoknts (equal flagella)
- Have a longitudinal and transverse flagellum resulting in a spinning or whirling motion
- Some produce saxitoxins (e.g., Alexandrium catenella)
- Prorocentrum micans are known for toxic algal blooms causing red tides.
- Some have light-sensitive organelles: ocelli or eyespots (e.g., Winowia and Erythropsidinium)
- Some have larger nuclei with prominent nucleoli
- Some have dinokaryon nuclei (in most but not all)
Other Protist groups:
-
Green algae:
- Unicellular, colonial, or multicellular (22,000+ species)
- Many live as single cells but some form filaments or macroscopic seaweeds (e.g., Volvox, Spirogyra)
- Have chloroplasts with two membranes and stacked thylakoids containing chlorophyll a and b
- Accessory pigments include beta-carotene & xanthophylls
- Cell walls often contain cellulose
- Have paired flagella for movement
-
Fungi-like protists:
- Slime molds (900+ species)
- Live as single amoeba-like cells that can aggregate to form multicellular reproductive structures or plasmodium
- Commonly decomposers, feeding on bacteria, yeasts, and fungi
- Play a role in molecular biology & genetics, possibly showing the ancestral mechanisms for multicellularity
- Cell walls composed of cellulose
- Water molds (Oomycetes)
- Cellular or acellular forms, often found in moist soil & surface waters
- Cell walls contain cellulose
- Heterotrophic (saprophytic, parasitic) - Some can destroy crops (e.g., Phytophthora infestans)
- Have complex life cycles, including asexual and sexual reproduction
- Often produce motile zoospores
- Slime molds (900+ species)
-
Brown Algae:
- Multicellular algae (1500-2000 species)
- Live in marine environments & important as food and habitat
- Body is a thallus, lacks complex xylem and phloem
- Have holdfast, stipe, and blade structures
- Have chloroplasts with 4 membranes containing fucoxanthin (pigment causing brown colors)
- Often form leafy, free-floating mats
- The simplest forms are filamentous (some species can grow very large and complex)
-
Red Algae:
- Multicellular (over 7,000 species), mostly marine
- Typically reproduce sexually, many are macroscopic
- Lack flagella and centrioles, store starch as floridean starch
- Chloroplast with two membranes, containing chlorophyll like some cyanobacteria, additionally contains chlorophyll a, along with accessory pigments like beta-carotene, lutein, & zeaxanthin
- Have a double cell wall, the outer layers containing the polysaccharides agarose & agaropectin, while internal walls are made predominantly of cellulose
- Used in industrial applications
Quizzes & Other information
- Questions and answers regarding different protist groups; e.g., which group Sargassum (brown algae) belongs to, origin of agar, process of meiosis, etc.
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Description
Test your knowledge on the biology and ecology of Euglena mutabilis. This quiz covers aspects like photosynthesis, lipid content, and unique adaptations of Euglena. Challenge yourself to understand the significance of this organism in its ecosystem and its survival mechanisms.
