Questions and Answers
What type of organisms are the majority of bacteria classified as?
Which of the following types of archaebacteria are known to thrive in extremely salty environments?
What is a primary byproduct of methanogens found in the gut of ruminants?
Which of the following diseases is known to be caused by pathogenic eubacteria?
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How do bacteria primarily reproduce?
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What is a characteristic feature of mycoplasmas?
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What is the primary characteristic of eubacteria?
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Which of the following describes heterotrophic bacteria?
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What structure do cyanobacteria possess that allows them to perform photosynthesis?
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Which of the following is a function of chemosynthetic bacteria?
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Which of these shapes correctly identifies Spirillum bacteria?
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Where can bacteria typically be found?
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What is a unique feature of cyanobacteria compared to other bacteria?
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What role do nitrogen-fixing bacteria, like Nostoc and Anabaena, play in the ecosystem?
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Study Notes
General Overview of Bacteria
- Bacteria belong to the Kingdom Monera, the sole members of this kingdom.
- They are the most numerous microorganisms, found almost everywhere, including vast numbers in soil.
- Capable of surviving in extreme environments like hot springs, deserts, snow, and deep oceans.
Bacterial Classification by Shape
- Bacteria are classified into four major shapes:
- Coccus (spherical)
- Bacillus (rod-shaped)
- Vibrio (comma-shaped)
- Spirillum (spiral)
Eubacteria
- Thousands of eubacteria, or "true bacteria," are characterized by a rigid cell wall and flagella when motile.
- They are vital for various ecological processes, including nutrient recycling and decomposition.
Cyanobacteria
- Also known as blue-green algae, they contain chlorophyll a and are photosynthetic autotrophs.
- Can be unicellular, colonial, or filamentous; they thrive in freshwater, marine, or terrestrial habitats.
- Form gelatinous colonies and can cause blooms in polluted waters.
- Capable of nitrogen fixation in specialized cells called heterocysts (e.g., Nostoc, Anabaena).
Metabolic Diversity
- Bacteria exhibit extensive metabolic diversity; some are autotrophic, producing food from inorganic materials, while most are heterotrophic, relying on other organisms or dead organic matter.
- Chemosynthetic autotrophic bacteria oxidize inorganic substances (nitrates, nitrites, ammonia) to produce ATP, playing a critical role in nutrient cycles, including nitrogen and sulfur.
Heterotrophic Bacteria
- Most abundant in nature, with many functioning as decomposers.
- Important to human activities: they aid in milk curdling, antibiotic production, and nitrogen fixation in legumes.
Archaebacteria
- Thrive in extreme conditions, including saline (halophiles), hot springs (thermoacidophiles), and marshy environments (methanogens).
- Different cell wall structure enables survival in harsh habitats.
- Methanogens produce methane from the dung of ruminant animals, contributing to biogas production.
Eubacteria Specifics
- Some eubacteria can survive without oxygen and include pathogenic mycoplasma.
- Pathogenic bacteria can cause human and animal diseases, e.g., cholera, typhoid, tetanus, citrus canker.
- Bacteria primarily reproduce by fission and can produce spores under adverse conditions.
- Engage in primitive sexual reproduction through DNA transfer between individuals.
Mycoplasma
- Unique for lacking a cell wall; considered the smallest living cells.
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Description
Test your knowledge about Bacteria, the unique members of the Kingdom Monera. This quiz covers their characteristics, habitats, and classification based on their shapes. Challenge yourself to understand the diversity and significance of these microorganisms.
