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Gram positive vs gram negative vs archaea?
- Gram positive: Will stain with crystal violet dye, thick wall made of peptidoglycan
- Gram negative: Will not stain with crystal violet dye, thin wall of peptidoglycan surrounded by additional
- Archaea cell walls do not contain peptidoglycan
3 “structures” of bacteria with brief function
- Fimbriae: short, spikey “hairs” that provide anchorage
- Flagella: movement for cell, different than eukaryotic flagella
- Pili: Bridge connecting two bacteria for conjugation
- Bacillus: stick
- Coccus: sphere
- Spirillum: squiggly/spiral
Cyanobacteria evolutionary/ecological imp.
- Ecological: Involved in carbon cycle (photosynthesis) and nitrogen cycle (N-fixation)
- Evolutionary: believed to be precursor to chloroplasts in eukaryotes. Major group that changed the earth’s atmosphere.
Cyanobacteria photosynthesis information.
- Use chlorophyll a and b + unique accessory pigments called PHYCOBOILINS [phycoerythrin and phycocyanin]
- Thykaloids: photosynthetic membrane layers similar to plants
Types of cyanobacteria anatomy with vague description
- Filamentous: collection of bacteria cells that DON’T SEPARATE after binary fission
- -hormogonia are broken filaments that may start a new filament strand
- Colonial: secrete mucilaginious sheath to bind cells together
What’s a stromatolite?
- Stacked pattern of Ca2+ rich sediment created by cyanobacteria.
- Lime extracted from H2O and secreted around the filaments caused their creation
Describe cyanobacterial blooms
Part of Plankton (basis of food chain), but can explode in # (a bloom / red tide), and can release toxic compounds which affect the food chain.
In cyanobacteria where does N-fixation occur? What is the “endospore-like” cell called?
- Heterocysts are specialized cells that carry enzymes for N-fixation. VERY THICK WALL and darker center.
- Akinetes are “hibernating” cells that form in response to a harsh env. BIG OVAL CELLS.
2 Given endosymbyotic relationships
- Azolla can complex w/ cyanos for N-fixation
- Lichens are ½ cyano and ½ fungi