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Questions and Answers
Which term describes specialized cells in cyanobacteria that fix atmospheric nitrogen?
Which term describes specialized cells in cyanobacteria that fix atmospheric nitrogen?
What is the primary method of reproduction for the majority of bacteria?
What is the primary method of reproduction for the majority of bacteria?
What role do heterotrophic bacteria play in the ecosystem?
What role do heterotrophic bacteria play in the ecosystem?
What can trigger the production of spores in bacteria?
What can trigger the production of spores in bacteria?
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Which of the following diseases is caused by pathogenic bacteria?
Which of the following diseases is caused by pathogenic bacteria?
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Which type of protozoan is characterized by the presence of pseudopodia for movement and prey capture?
Which type of protozoan is characterized by the presence of pseudopodia for movement and prey capture?
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What is a common example of a parasitic flagellated protozoan that causes sleeping sickness?
What is a common example of a parasitic flagellated protozoan that causes sleeping sickness?
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Which of the following groups of protozoans actively moves using cilia?
Which of the following groups of protozoans actively moves using cilia?
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What is the major infectious agent of malaria?
What is the major infectious agent of malaria?
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Which type of organisms are classified under the kingdom Fungi?
Which type of organisms are classified under the kingdom Fungi?
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What is a significant characteristic of dinoflagellates?
What is a significant characteristic of dinoflagellates?
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How do euglenoids adapt when sunlight is not available?
How do euglenoids adapt when sunlight is not available?
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What do slime moulds produce under unfavorable conditions?
What do slime moulds produce under unfavorable conditions?
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What distinguishes protozoans from other protists?
What distinguishes protozoans from other protists?
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Which of the following is true about the pigments of euglenoids?
Which of the following is true about the pigments of euglenoids?
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What type of spores are produced endogenously in sac-like asci?
What type of spores are produced endogenously in sac-like asci?
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What is the primary structure where basidiospores are formed?
What is the primary structure where basidiospores are formed?
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Which of the following is a characteristic of deuteromycetes?
Which of the following is a characteristic of deuteromycetes?
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Which of these organisms is commonly classified under basidiomycetes?
Which of these organisms is commonly classified under basidiomycetes?
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What type of reproduction is common among basidiomycetes?
What type of reproduction is common among basidiomycetes?
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Which structure in fungi consists of long, slender thread-like structures?
Which structure in fungi consists of long, slender thread-like structures?
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What is the primary component of fungal cell walls?
What is the primary component of fungal cell walls?
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What type of hyphae have cross walls?
What type of hyphae have cross walls?
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What is the asexual reproduction process in fungi typically called?
What is the asexual reproduction process in fungi typically called?
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Which of the following is a heterotrophic lifestyle of fungi?
Which of the following is a heterotrophic lifestyle of fungi?
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What is the first step of the sexual reproduction cycle in fungi?
What is the first step of the sexual reproduction cycle in fungi?
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Which type of spores are produced during fungal sexual reproduction?
Which type of spores are produced during fungal sexual reproduction?
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What do we call fungi that live in a symbiotic relationship with algae?
What do we call fungi that live in a symbiotic relationship with algae?
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Study Notes
Cyanobacteria
- Unicellular, colonial, or filamentous organisms
- Found in freshwater, marine, or terrestrial environments
- Colonies often surrounded by a gelatinous sheath
- Can form blooms in polluted water bodies
- Some can fix atmospheric nitrogen in specialized cells called heterocysts, e.g., Nostoc and Anabaena
Chemosynthetic Autotrophic Bacteria
- Oxidize inorganic substances (nitrates, nitrites, ammonia)
- Use energy released from oxidation for ATP production
- Play a key role in recycling nutrients like nitrogen, phosphorus, iron, and sulfur
Heterotrophic Bacteria
- Most abundant bacteria
- Majority are important decomposers
- Have various impacts on human affairs, including:
- Curd production
- Antibiotic production
- Nitrogen fixation in legume roots
- Some are pathogens causing diseases like cholera, typhoid, tetanus, and citrus canker
- Reproduce mainly by fission
- Can produce spores under unfavorable conditions
- Can reproduce by a primitive type of DNA transfer
Mycoplasma
- Lack a cell wall
Dinoflagellates
- Mostly marine and photosynthetic
- Appear in various colors (yellow, green, brown, blue, red) depending on pigments
- Have a cell wall with stiff cellulose plates
- Possess two flagella (one longitudinal, one transverse)
- Some can cause red tides (rapid multiplication)
- Toxins released during red tides can kill marine animals
Euglenoids
- Mostly freshwater organisms
- Have a protein-rich layer called a pellicle instead of a cell wall
- Have two flagella (one short, one long)
- Photosynthetic in the presence of sunlight, but can behave like heterotrophs in its absence
- Have pigments similar to higher plants
- Example: Euglena
Slime Moulds
- Saprophytic protists
- Move along decaying materials engulfing organic matter
- Form an aggregation called a plasmodium under suitable conditions
- Form fruiting bodies with spores during unfavorable conditions
- Spores are resistant and can survive for years
Protozoans
- All heterotrophic
- Live as predators or parasites
- Believed to be primitive relatives of animals
- Four major groups:
Amoeboid Protozoans
- Found in freshwater, seawater, or moist soil
- Move and capture prey using pseudopodia (false feet)
- Some are parasites (e.g., Entamoeba)
Flagellated Protozoans
- Free-living or parasitic
- Possess flagella
- Some parasitic forms cause diseases (e.g., sleeping sickness caused by Trypanosoma)
Ciliated Protozoans
- Aquatic and actively moving due to cilia
- Have a gullet for feeding
- Example: Paramoecium
Sporozoans
- Have an infectious spore-like stage in their life cycle
- Example: Plasmodium (malaria parasite)
Kingdom Fungi
- Heterotrophic organisms
- Diverse in morphology and habitat
- Can be found in air, water, soil, on animals, and plants
- Prefer warm and humid places
General Features of Fungi
- Mostly filamentous (with the exception of yeasts)
- Consists of long, slender threads called hyphae
- Network of hyphae is called mycelium
- Can have coenocytic hyphae (continuous tubes with multinucleated cytoplasm) or septate hyphae (cross walls between cells)
- Cell walls composed of chitin and polysaccharides
- Heterotrophic and absorb soluble organic matter
Nutritional Modes of Fungi
- Saprophytes: Feed on dead substrates
- Parasites: Feed on living plants and animals
- Symbionts: Live in association with other organisms
- Lichens: Association with algae
- Mycorrhiza: Association with roots of higher plants
Reproduction in Fungi
- Vegetative Reproduction: Fragmentation, fission, budding
- Asexual Reproduction: Spores (conidia, sporangiospores, zoospores)
- Sexual Reproduction: Spores (oospores, ascospores, basidiospores) produced in fruiting bodies
Sexual Reproduction in Fungi
- Involves three steps:
- Plasmogamy: Fusion of protoplasms
- Karyogamy: Fusion of nuclei
- Meiosis: Haploid spores produced from zygote
Ascomycetes
- Produce ascospores endogenously in asci (sac-like structures)
- Asci are arranged in ascocarps (fruiting bodies)
- Examples: Aspergillus, Claviceps, Neurospora
- Some are edible (e.g., morels, truffles)
Basidiomycetes
- Include mushrooms, bracket fungi, and puffballs
- Found in soil, on logs, and living plant bodies
- Mycelium is branched and septate
- Generally lack asexual spores, but vegetative reproduction by fragmentation is common
- Lack sex organs, plasmogamy occurs by fusion of vegetative cells
- Resultant structure is dikaryotic and gives rise to basidium
- Karyogamy and meiosis occur in the basidium, producing basidiospores
- Basidiospores are exogenously produced on the basidium
- Basidia are arranged in basidiocarps (fruiting bodies)
- Examples: Agaricus (mushroom), Ustilago (smut), Puccinia (rust fungus)
Deuteromycetes
- Imperfect fungi because only the asexual or vegetative stages are known
- Sexual forms were later discovered and placed in other fungal classes
- Some fungi may have asexual and sexual stages named differently and placed in different classes
- Once linkages were established, they were moved out of deuteromycetes
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Description
Explore the diverse world of bacteria through this quiz that covers cyanobacteria, chemosynthetic autotrophic bacteria, and heterotrophic bacteria. Learn about their characteristics, roles in ecosystems, and importance in human affairs. Perfect for students of microbiology and environmental science.
