BI 305 Exam 4 Chp 18 and 21 Flashcards
What is a phylum?
Phylum=group of organisms with a common ancestor that diverged early from other bacteria.
What are the advantages and disadvantages of akinetes and hormogonia?
Akinetes=spores produced by cyanobacteria.
Hormogonia=mobile short chains of cyanobacteria.
Akinetes: Advantage: Can very harsher environments. Disadvantage: Not growing until germinated. Cannot move on its own.
Hormogonia: Advantage: Can continue to grow. Not a free-living cell so can work with others to survive. Allows for differentiation. Can travel. Disadvantage: Can die easier.
What is the advantage for Streptomyces to produce antibiotics?
Can kill neighboring cells and others that would kill it.
Can use dead cells for nutrients.
Destroys competition.
Why did it take so long for scientists to discover bacteria’s ability to form biofilms?
Focus on identification and pure culture played a big role.
Bias towards microbes not being complex.
May have decreased funding for looking into the function of bacteria.
Assumed that beyond E. coli, knowing how microbes worked was not important.
What are deep-branching taxa?
Deep-branching taxa=taxonomic groups that diverged early before well-known phyla were formed.
What are Gram-variable organisms?
Gram-variable organisms=organisms that do not always have the same results under Gram-staining.
What are emerging clades?
Emerging clades=recently defined or characterized clades.
What is monophyletic?
Monophyletic=one clade with a single common ancestor.
What is polyphyletic?
Polyphyletic=many clades that branch among different genera.
What are oligotrophs?
Oligotrophs=cells with unusual shapes that enhance nutrient uptake in low nutrient environments.
What are thylakoids?
Photomembranes in bacteria.
How are cyanobacteria different from other phototrophic organisms?
Many bacteria can be phototrophic but only cyanobacteria use photosystem 1 + 2, and chlorophyll a and b.
What does anoxic mean?
Anoxic=without oxygen.
What are carboxysomes?
Carboxysomes=where dark reactions take place.
What are gas vesicles?
Gas vesicles help to retain buoyancy in the water.
What are hormogonia?
Hormogonia=short mobile chains for cyanobacteria.
What are akinetes?
Spore cells for cyanobacteria.
What are baeocytes?
Spore cells for cyanobacteria that Myxosacrina produce.
What are heterocysts?
Nitrogen-fixing cells that differentiate from aerobic cyanobacteria.
What does monoderm membrane mean?
1 membrane.
What does diderm membrane mean?
2 membranes.
What are methylotrophs?
Methyltrophs can metabolize single carbon molecules.
What is leghemoglobin?
A protective compound that binds oxygen and keeps the rhizobia in an anaerobic environment.
What are nitrifers?
Nitrifiers=ammonia to nitrite or nitrite to nitrate.
What is the life cycle of a bdellovibiro?
Bdellovibrio=deltaproteobacteria.
Finds host cell by chemotaxis.
Binds to host receptors.
Invades periplasm and uses host resources to grow.
Generates enzymes to enter the cytoplasm.
Degrades host macromolecules and makes them available to them.
The entire host cell loses its shape as it becomes an incubator for these bacteria.
Bdellovibrio grows in a spiral chain and fragments and flagellated cells.
Host lyses and bdellovibrio is released.
What is the life cycle of a chlamydiae bacterium from the PVC Superphylum?
Life cycle:
The elementary body (a spore) is taken into a host.
Grows into a reticulate body.
Can grow and site for a long time.
Makes a new elementary body.
New elementary bodies lyse cell and find a new host.
What are the common characteristics of cyanobacteria?
Uses thylakoid and two photosystems.
Uses chlorophyll a and b.
Only phototrophs that can photolyze water.
Where most of Earth’s oxygen comes from.
Share a common metabolism but differ in shape and environment.
What are Nostoc?
Nostoc=cyanobacteria with thyalkoids distributed throughout the cell.
What are Prochlorococcus?
Prochlorococcus=cyanobacteria with concentric circles of thylakoids.
What is Prochlorococcus marinus?
Prochlorococcus marinus is a cyanobacteria and the smallest and most abundant oxygen producer.
What is Microcystis?
Microcystis=cyanobacterial genus that produces microcystins, a toxin.
Becomes more abundant during nitrogen and phosphorous runoffs.
What are Oscillatora?
Oscillatoria=cyanobacteria that can form hormogonia.
What are Anabaena?
Anabaena=cyanobacteria that can form spore cells called akinetes.
What are Myxosacrina?
Myxosacrina=cyanobacteria that can form large cell aggregates and release baeocytes to reproduce.
What are common characteristics of Firmicutes, Tenericutes, and Actinobacteria?
Gram-positive.
1 membrane
Except for mycobacterium.
What are common characteristics of Firmicutes?
Thick peptidoglycan cell wall.
Low GC content.
Well-developed S layer of glycoproteins.
What are Bacillus?
Bacillus=spore producing firmicutes.
What is Bacillus thuringiensis?
Bacillus thuringiensis= firmicutes of great economic importance as an insecticide.
During sporulation, it forms a diamond-shaped endotoxin.
Activated by high pH in insect tracts.
Is not activated in the human digestive tracts.
What are Clostridium?
Clostridium=spore producing firmicute.
Polyphyletic spore-forming anaerobes.
More than one ancestor.
C. tetani.
What are Clostridium botulinum?
Under Clostridium, a spore-producing firmicute.
C. botulinum is commercially and medically important for the botulinum toxin.
Botox paralyzes muscles.
What are Lactobacillales?
Lactobacillales=non-spore-producing aerotolerant firmicutes that produce lactic acid and are used to produce sauerkraut and cheese.
What are Listeria and Streptococcus?
Listeria and Streptococcus=firmicutes that are well-known human pathogens.
What is Listeria monocytogenes?
Listeria monocytogenes= firmicutes; can survive phagocytic vesicles and multiply in the cytoplasm.
Generates actin tails that project it into neighboring cells.
Uses the actin cytoskeleton of the host to move.
What are common characteristics of tenericutes?
Lack cell wall, and require an animal host.
Holds shape via the cytoskeleton.
Tenericutes=Mycoplasms=Mollicutes.
What are mycoplasma?
Mycoplasma=tenericute that can lead to human pneumonia and meningitis.
What are actinobacteria?
Thick peptidoglycan cell wall.
High GC content.
What are mycobacterium?
Mycobacterium= actinobacteria with a waxy cell covering and more than 1 membrane.
Cell covering includes mycolic acids.
Waxy outer covering.
Harder to get things across the covering.
This includes nutrients too so that’s why they are slow-growing.
Very defensive.
What is M. tuberculosis?
M. tuberculosis=actinobacteria mycobacterium that causes tuberculosis.