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What are the three basic shapes of prokaryotic cells?
What are the three basic shapes of prokaryotic cells?
Spherical cocci, rod-shaped bacilli, and spirals.
What are some of the other variations in shapes of prokaryotic cells?
What are some of the other variations in shapes of prokaryotic cells?
Vibrios, coccobacilli, and pleomorphic.
What is the shape of cocci?
What is the shape of cocci?
Spherical.
What shape do bacilli have?
What shape do bacilli have?
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How do prokaryotes reproduce?
How do prokaryotes reproduce?
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What is binary fission?
What is binary fission?
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All prokaryotes reproduce sexually.
All prokaryotes reproduce sexually.
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A bacillus is a bacterium with a slightly curved rod shape.
A bacillus is a bacterium with a slightly curved rod shape.
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If you were to view staphylococci, you should expect to see clusters of cells.
If you were to view staphylococci, you should expect to see clusters of cells.
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Initial bodies are stable resting stages that do not metabolize but will germinate when conditions improve.
Initial bodies are stable resting stages that do not metabolize but will germinate when conditions improve.
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Archaea are classified into phyla based primarily on tRNA sequences.
Archaea are classified into phyla based primarily on tRNA sequences.
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Halophiles inhabit extremely saline habitats such as the Great Salt Lake.
Halophiles inhabit extremely saline habitats such as the Great Salt Lake.
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Pigments located in thylakoids in phototrophic bacteria trap light energy for metabolic processes.
Pigments located in thylakoids in phototrophic bacteria trap light energy for metabolic processes.
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Most cyanobacteria form heterocysts in which nitrogen fixation occurs.
Most cyanobacteria form heterocysts in which nitrogen fixation occurs.
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When environmental nutrients are depleted, myxobacteria aggregate in mounds to form fruiting bodies.
When environmental nutrients are depleted, myxobacteria aggregate in mounds to form fruiting bodies.
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The definition provided is True.
The definition provided is True.
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What is Bacillus anthracis associated with?
What is Bacillus anthracis associated with?
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What is Veillonella associated with?
What is Veillonella associated with?
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What does Clostridium perfringens cause?
What does Clostridium perfringens cause?
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What is Clostridium botulinum known for?
What is Clostridium botulinum known for?
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What is Bacillus licheniformis associated with?
What is Bacillus licheniformis associated with?
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What condition is caused by Streptococcus?
What condition is caused by Streptococcus?
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What is Streptomyces associated with?
What is Streptomyces associated with?
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What does Corynebacterium diphtheriae cause?
What does Corynebacterium diphtheriae cause?
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What is Gluconobacter associated with?
What is Gluconobacter associated with?
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What disease is caused by Bordetella?
What disease is caused by Bordetella?
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What is Zoogloea associated with?
What is Zoogloea associated with?
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What role does Azotobacter play in the environment?
What role does Azotobacter play in the environment?
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What does Desulfovibrio cause?
What does Desulfovibrio cause?
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Chlamydia is associated with what condition?
Chlamydia is associated with what condition?
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What damage can Cytophaga cause?
What damage can Cytophaga cause?
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What is the name of the type of reproduction in prokaryotes that results in a palisade arrangement of cells?
What is the name of the type of reproduction in prokaryotes that results in a palisade arrangement of cells?
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What are the thick-walled reproductive spores produced in the middle of cyanobacterial filaments called?
What are the thick-walled reproductive spores produced in the middle of cyanobacterial filaments called?
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What best describes stiff, spiral-shaped prokaryotic cells?
What best describes stiff, spiral-shaped prokaryotic cells?
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Halobacterium salinarium is distinctive because it depends on what?
Halobacterium salinarium is distinctive because it depends on what?
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What type of bacteria are photosynthetic bacteria that also fix nitrogen?
What type of bacteria are photosynthetic bacteria that also fix nitrogen?
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Which genus is the most common anaerobic human pathogen?
Which genus is the most common anaerobic human pathogen?
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What is the name of the flexible, spiral-shaped prokaryotes?
What is the name of the flexible, spiral-shaped prokaryotes?
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What type of bacteria convert nitrogen gas into ammonia?
What type of bacteria convert nitrogen gas into ammonia?
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What characteristic is associated with Mycobacterium due to mycolic acid in the cell wall?
What characteristic is associated with Mycobacterium due to mycolic acid in the cell wall?
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Study Notes
Prokaryotic Cell Shapes
- Three basic shapes: cocci (spherical), bacilli (rod-shaped), and spirals (stiff spirilla or flexible spirochetes).
- Variations include vibrios (curved rods), coccobacilli (intermediate), and pleomorphic (variable shapes).
Reproductive Methods in Prokaryotes
- Asexual reproduction methods: binary fission, snapping division, spore formation, and budding.
- Binary fission is the most common, where a cell replicates its DNA and divides into two cells.
Endospore Formation
- Gram-positive Bacillus and Clostridium genera can form endospores which develop into vegetative cells.
- Endospores can be formed centrally, terminally, or sub-terminally within cells.
Types of Archaea
- Lack peptidoglycan in cell walls; lipids have branched hydrocarbon chains.
- Reproduce by binary fission, budding, or fragmentation; found in moderate conditions and some in the human microbiome.
Extremophiles
- Archaea that thrive in extreme conditions, such as thermophiles (high temperatures) and halophiles (high salinity).
Thermophiles and Hyperthermophiles
- Thermophiles: require temperatures above 45ºC, used in recombinant DNA technology.
- Hyperthermophiles: require temperatures over 80ºC.
Halophiles
- Live in environments with high salinity, requiring more than 9% NaCl for cell wall integrity.
- Most studied example: Halobacterium salinarium.
Methanogens
- Largest group of Archaea; convert carbon dioxide and hydrogen to methane gas.
- Important in sewage treatment and prevalent in animal colons, particularly humans.
Deeply Branching Bacteria
- Represent some of the earliest forms of life, often autotrophic and found in extreme environments.
Phototrophic Bacteria
- Use light as an energy source through photosynthetic lamellae; most are photoautotrophs.
Cyanobacteria
- Known for nitrogen fixation, converting atmospheric nitrogen to ammonia.
Proteobacteria Overview
- Largest and most diverse group of gram-negative bacteria, classified into five classes: alpha, beta, gamma, delta, and epsilon.
Alphaproteobacteria
- Nitrogen fixers like Azospirillium and Rhizobium are important in agriculture.
- Some are human pathogens like Rickettsia (causes typhus) and Brucella (causes brucellosis).
Betaproteobacteria
- Includes pathogenic Neisseria species responsible for gonorrhea and meningitis.
- Bordetella pertussis causes whooping cough.
Gammaproteobacteria
- Largest class; includes intracellular pathogens like Legionella (causes Legionnaire's Disease) and Coxiella (causes Q fever).
- Many are part of intestinal flora, including disease-causing species like Escherichia coli and Salmonella.
Deltaproteobacteria
- Includes Desulfovibrio (reduces sulfate) and Bdellovibrio (invades gram-negative bacteria).
Epsilonproteobacteria
- Curved or spiral-shaped bacteria; Campylobacter causes gastroenteritis and Helicobacter pylori leads to gastric ulcers.
Chlamydias
- Gram-negative cocci and the most common STD in the US; cause diseases like trachoma and pneumonia.
Spirochetes
- Flexible, helical bacteria; Treponema pallidum causes syphilis, and Borrelia burgdorferi is responsible for Lyme disease.
Key Gram-Positive Bacteria
- Mycoplasmas: smallest bacteria, lack cell walls; cause infections like walking pneumonia.
- Bacillus: aerobic, soil bacteria that can produce toxins like anthrax (Bacillus anthracis).
- High G+C bacteria: include Corynebacterium and Mycobacterium (causes tuberculosis and leprosy).
Key Terminology
- Snapping division: characteristic reproduction method leading to palisade arrangement in bacilli.
- Akinetes: thick-walled spores in cyanobacterial filaments.
- Nitrogen fixers: prokaryotes that convert nitrogen gas to ammonia.
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Description
Test your knowledge on the shapes, reproduction, and unique characteristics of prokaryotic cells. This quiz covers fundamental concepts including endospore formation and the diversity of archaea. Ideal for biology students looking to understand microbial life.
