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Questions and Answers
What is the primary way pathogenic bacteria cause disease?
What is the primary way pathogenic bacteria cause disease?
What is the role of horizontal gene transfer in pathogenic bacteria?
What is the role of horizontal gene transfer in pathogenic bacteria?
Which bacterium is commonly used in gene cloning?
Which bacterium is commonly used in gene cloning?
What is bioremediation primarily used for?
What is bioremediation primarily used for?
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Which statement about endotoxins is true?
Which statement about endotoxins is true?
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What distinguishes prokaryotes from eukaryotes?
What distinguishes prokaryotes from eukaryotes?
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Which of the following best describes the size of most prokaryotic cells?
Which of the following best describes the size of most prokaryotic cells?
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In what environments can prokaryotes thrive?
In what environments can prokaryotes thrive?
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What is the primary function of a capsule in prokaryotes?
What is the primary function of a capsule in prokaryotes?
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What are the two primary lineages of prokaryotes?
What are the two primary lineages of prokaryotes?
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Which of the following is NOT a common shape of prokaryotes?
Which of the following is NOT a common shape of prokaryotes?
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Which structures are primarily responsible for the motility in prokaryotes?
Which structures are primarily responsible for the motility in prokaryotes?
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What type of DNA structure do prokaryotes possess?
What type of DNA structure do prokaryotes possess?
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What is the primary method of reproduction for prokaryotes?
What is the primary method of reproduction for prokaryotes?
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How do fimbriae assist prokaryotes?
How do fimbriae assist prokaryotes?
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Which process involves a prokaryotic cell taking up foreign DNA from its environment?
Which process involves a prokaryotic cell taking up foreign DNA from its environment?
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What term describes the movement of genes between bacteria through viruses?
What term describes the movement of genes between bacteria through viruses?
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What is a characteristic of endospores in prokaryotes?
What is a characteristic of endospores in prokaryotes?
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What is one of the main contributors to genetic diversity in prokaryotes?
What is one of the main contributors to genetic diversity in prokaryotes?
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What type of movement does positive taxis refer to in prokaryotes?
What type of movement does positive taxis refer to in prokaryotes?
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What defines the presence of a nucleus in eukaryotic cells compared to prokaryotic cells?
What defines the presence of a nucleus in eukaryotic cells compared to prokaryotic cells?
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Which of the following accurately describes prokaryotic generation times?
Which of the following accurately describes prokaryotic generation times?
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Which of the following organisms is likely to be antibiotic resistant?
Which of the following organisms is likely to be antibiotic resistant?
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In prokaryotes, what is the effect of rapid reproduction on mutations?
In prokaryotes, what is the effect of rapid reproduction on mutations?
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Which of these accurately describes the process of conjugation in prokaryotes?
Which of these accurately describes the process of conjugation in prokaryotes?
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What is the primary reason prokaryotes evolve rapidly?
What is the primary reason prokaryotes evolve rapidly?
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What is a common pathogenic parasite mentioned in the content?
What is a common pathogenic parasite mentioned in the content?
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What role do chemoheterotrophic prokaryotes primarily serve in ecosystems?
What role do chemoheterotrophic prokaryotes primarily serve in ecosystems?
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Which type of ecological interaction is characterized by one organism benefiting while the other is neither helped nor harmed?
Which type of ecological interaction is characterized by one organism benefiting while the other is neither helped nor harmed?
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Which group of bacteria is known for their role in antibiotic production?
Which group of bacteria is known for their role in antibiotic production?
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What significant impact do prokaryotes have on plant growth?
What significant impact do prokaryotes have on plant growth?
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Which characteristic distinguishes cyanobacteria from other bacteria?
Which characteristic distinguishes cyanobacteria from other bacteria?
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What is one way that mutualistic bacteria in human guts benefit their host?
What is one way that mutualistic bacteria in human guts benefit their host?
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Which of the following correctly describes proteobacteria?
Which of the following correctly describes proteobacteria?
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What is the primary function of a sex pilus in bacteria?
What is the primary function of a sex pilus in bacteria?
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Which type of prokaryote is poisoned by oxygen and relies on fermentation?
Which type of prokaryote is poisoned by oxygen and relies on fermentation?
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What significant classification change occurred due to molecular systematics?
What significant classification change occurred due to molecular systematics?
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Which of the following statements is true about methanogens?
Which of the following statements is true about methanogens?
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What characteristic is NOT associated with chlamydias?
What characteristic is NOT associated with chlamydias?
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What environment do extremophiles most likely inhabit?
What environment do extremophiles most likely inhabit?
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Which prokaryotic group includes organisms that predominantly rely on fermentation?
Which prokaryotic group includes organisms that predominantly rely on fermentation?
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What is the role of facultative anaerobes in relation to oxygen?
What is the role of facultative anaerobes in relation to oxygen?
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Study Notes
Prokaryotes - Monera - Biodiversity
- Prokaryotes are the first organisms on Earth
- They lack a nucleus and are mostly unicellular
- Most prokaryotic cells are 0.5-5μm in diameter, much smaller than eukaryotic cells (10-100μm) — exception: Thiomargarita namibiensis (750μm)
- Prokaryotes are smaller and simpler than eukaryotes, but make up for it in numbers
- They thrive in almost all environments, including extreme conditions (acidic, salty, cold, hot) that are unsuitable for most other organisms
- Divided into two lineages: Bacteria and Archaea
- Both are prokaryotes, belonging to Kingdom Monera
Features of Prokaryotes
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Shape:
- Spherical (cocci): single, pairs, chains, clusters
- Rod-shaped (bacilli): single, chains
- Spiral: comma-like, loose coils, corkscrew-shaped -Exceptions: Flat and square-shaped Haloquadratum walsbyi
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Cell-surface structure:
- Cell wall maintains cell shape, protects from bursting in hypotonic environments for nearly all prokaryotes
- Eukaryotic cell walls are made of cellulose or chitin
- Bacterial cell walls contain peptidoglycan, a network of sugar polymers cross-linked by polypeptides
- Archaeal cell walls contain a variety of polysaccharides and proteins but lack peptidoglycan
- Gram-staining differentiates bacteria based on the amount of peptidoglycan in the cell wall: -Gram-positive bacteria have a thick peptidoglycan layer and stain purple -Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane and stain red
- Capsule: sticky layer of polysaccharide or protein around the cell wall for protection and adherence
- Slime layer: a less organized, sticky layer, which also helps with adherence.
- Endospores: tough, multi-layered resistant cells formed by some when nutrients are scarce
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Motility:
- Some prokaryotes use flagella for movement
- Flagella are motor, hook, and filament parts
-
Internal organization and DNA:
- Simpler than those of eukaryotes
- No membrane-enclosed organelles
- Less DNA (circular chromosome with few proteins)
- Often possess plasmids (small rings of DNA)
- DNA lies in a nucleoid area within the cell.
- Specialised metabolic membranes (infoldings of the plasma membrane) for different functions
-
Reproduction:
- Binary fission: a single cell divides into two identical cells
- Rapid reproduction rates allow for quick adaptations
-
Mode of Nutrition:
- Autotrophs make their own food: -Photoautotrophs use light -Chemoautotrophs use inorganic molecules,
- Heterotrophs consume organic compounds as food: -Photoheterotrophs use light -Chemoheterotrophs consume organic molecules.
Factors Influencing Genetic Diversity
- Prokaryotes show substantial genetic variation
- Main factors:
- Rapid reproduction
- Mutation
- Genetic recombination
Genetic Recombination
- Combining DNA from different sources
- Key methods include: -Transformation -Transduction -Conjugation
Roles of Prokaryotes in the Biosphere
-
Chemical Recycling:
-Decomposers break down dead organisms and waste products
- Increase the availability of nitrogen, phosphorus, and potassium for plant growth
- Ecological Interactions: -Symbiosis (live in close contact) -Mutualistic: both benefit -Commensalism: one benefits, the other is unaffected -Parasitic: one benefits, the other is harmed, but not killed; Pathogens are parasitic microorganisms that cause disease
- Impact on humans: -Mutualistic: live in the human gut, aid in digestion -Pathogenic: cause disease; many diseases are caused by prokaryotes; Toxins cause disease (exotoxins released by the organism even if it is dead, endotoxins released by cell lysis)
Prokaryotes in Research & Technology
- Used for DNA technology like gene cloning
- Produce enzymes like Taq DNA polymerase for PCR
- Bioremediation: clearing pollutants
- Produce vitamins, antibiotics, and hormones
- Produce bio-plastics
Archaea
- Some live in extreme environments
- Include extreme halophiles (salt-loving), extreme thermophiles (heat-loving), and methanogens (methane-producing organisms)
Bacteria
- Wide diversity, including: -Chlamydias (live within animal cells) -Spirochetes (spiral-shaped bacteria) -Cyanobacteria (photosynthetic bacteria) -Gram-positive bacteria (thick peptidoglycan layer) -Proteobacteria (diverse, includes aerobes and anaerobes)
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Description
Explore the fascinating world of prokaryotes, the first organisms on Earth. Learn about their unique characteristics, classification, and environments they thrive in, including extreme conditions. This quiz covers essential aspects of Monera and their diverse shapes and structures.
