Ch27 Bacteria & Archaea
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- Prokaryotic-Lack nucleus
- More resistant to heat and other extreme
- Found in moderate conditions
- Occupy habitats with very high salt content, acidity or methane levelsm or high temperatures.
- Methanopyrus grows in deep sea thermal vents at 98 C-Hyperthermophile
- Sulfolobus grows in hot springs at pH 3
- 50 or so bacterial phyla-Structural and metabolic features of half unknown
- Some are extremeophiles but many more bacteria favor moderate conditions
- Form symbiotic relationships with eukaryotes
- Photosynthetic bacteria abundant in fresh waters, oceans and wetlands and on surface of arid soils
- Named for blue-green (cyan) color
- Only prokaryotes that generate
- Gave rise to plastids of eukaryotic algae and plants
- Display greates structual diversity found among bacterial phyla
- Essential ecological roles in producing organic carbon and fixing nitrogen
Eukaryotic nucleus and cytoplasm
likely arose in an ancient archaeal organism
Mitochandria and plastids
orginated from proteobacteria and cyanobacteria by endosymbiosis
Bacteria and Archaea
- Share small size, rapid growth and simple cellular structure
- Are 1-5um in diameter
- limits the amt of materials that can be stored within cells but allows faster cell division
What are the five major shapes?
- Spheres- cocci
- Rods- bacilli
- Comma-Shaped- vibrios
- Spiral-shaped Spirochaetes r flexible & spirilli r rigid
Some occur as single cells, pairs and filaments
- Sometimes called Glycocalyx
- Composed of polysacc., protein or both
- Secreted from cells
- Fxn: Evade host defenses
- Hold colony together
- Most hv rigid cell wall outside the PM
- Maintain cell shape and help protect agant attack
- Help to avoid lysis in hypotonic soltion
Archaea and some bacteria use protein where as most bacteria use peptidoglycan
What is gram positive?
- Thick peptidoglycan layer
- Purple dye held in thick layer
- Cells are stained purple
- Vulnerable to pencillin that interferes in cell wall synethesis
What is gram negative?
- Less peptidoglycan and a thin outer envelope of lipopolysac.
- Lose purple stain but retain final pink stain
- Cells are stained pink
- Resists pencillin and requires other antibios'
What is their motility?
- Move to favorable conditions
- Respond to chemical signals
Switch, twitch, glide or adjust floatation
What is Flagella?
- Different in eukaryotic flagella
- Like an outboard boat motor
- Differ in number and location of flagella
What is Pili?
- Twitch or glide across surface
- Threadlike cell surface structures
- Play import roles in bacterial reprod and dz processes
What is binary fusion?
divide by splitting in two
What is Akinetes?
- Found in aquatic filamentous cyanbact
- Develop when winter approaches
- Survive winter and produce new filaments in spring
What is Endospores?
- Tough protein coat
- Amazingly long dormant span
- Found in some Gram-pos bacteria
IE: Bacillus antracis, Clostridium botulinum, Clostridium tetani
How they obtain their genetic material?
- Transduction: Via viral vector
- Transformation: Via uptake of DNA from environment
- Conjugation: Via mating with another cell
What is Autotrophs?
Produce all or most of their own organic compounds
What is Photoautotroph?
Use light as energy source for synthesis of organic compds frm CO2 or H2S.
What is Chemoautotrophs?
Use energy obtained from chemical modification of inorganic compds to synthesize organic compds
What is Heterotrophs?
Organisms that require at least one organic compd and often more
What is Photoheterotroph?
Able to use light energy to make ATP but they must take in organic compds from the envirnmt
What is Chemoorgantroph?
Must obtain organic molecules for both energy and carbon source.
What is Obligate?
What is Facultative aerobes?
can use oxygen or not
What is Obligate Anaerobes?
cannot tolerate oxygen
What is Aeortorlerant anaerobes?
Do not use oxygen but are not poisoned by it
What is envoles of Carbon cycle?
- Producers synthesize organic compds used by other organisms as food
- Decomposers break down dead organisms to release minerals for reuse
- Methanogens-makes methane
- Methanotrophs- consume methane
What is Symbosis
An organism that lives in close association with one or more other organisms
What is Parasitism?
One partner benefits at the expense of the other
What is Mutualism?
Association beneficial to both partners
What is Syntrophy?
Some bacteria live together and supply each other with essential nutrients
What is Consortia?
Larger community of nutrient exchangers.
IE: Marine worm with no mouth, gut, or anus depends on bacteria inside it for food and waste recycyling
Associations with Eukaryotes
- Bacteria induces normal development in Ulva
- Bioluminescent bacteria in squid and other animals
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