Lecture 22 - Prokaryotes 2 Flashcards
What is the most diverse domain?
bacteria
What are the two domains of prokaryotes?
- bacteria
2. archaea
Where did chloroplasts come from?
cyanobacteria
What has allowed for more rapid sequencing of prokaryote genomes?
The use of polymerase chain reaction (PCR)
What obscures the root of the tree of life?
horizontal gene transfer between prokaryotes
What are the 3 domains of life?
- Bacteria
- Archaea
- Eukarya
Bacteria include the vast majority of _______ species
prokaryotic
What are proteobacteria?
- gram-negative bacteria
- include photoautotrophs, chemoautotrophs, heterotrophs
- some anaerobic, others aerobic
What are the 5 subgroups of proteobacteria?
- alpha
- beta
- gamma
- delta
- epsilon
Many species of alpha proteobacteria are closely associated with __________
eukaryotic hosts
What are 2 examples of alpha proteobacteria?
- Rhizobium
2. Agrobacterium
What do scientists hypothesize about mitochondria?
evolved from aerobic alpha proteobacteria through endosymbiosis
What is an example of a beta proteobacteria?
Nitrosomonas (soil bacterium)
What is nitrification?
converting NH4+ to NO2-
What is an example of a gamma proteobacteria?
- sulfur bacteria Thiomargarita namibiensis
2. pathogens Legionella, Salmonella, Vibrio cholerae, E. Coli
What are examples of a delta proteobacteria?
- myxobacteria
2. bdellovibrios
What are examples of epsilon proteobacteria?
- pathogens Campylobacter, Helicobacter pylori
What are Chlamydias
- parasits
- causes blindless
- sexual transmission
What are Spirochetes?
- helical hetertrophs
- some are parasites (Treponema pallidum, causes syphilis)
What are cyanobacteria?
- photoautogrophs that generate O2
- evolved into chloroplasts by endosymbiosis
What is the chem. reaction for photosynthesis?
CO2 + H2O —> CH2O + O2
When did stromatolites die out?
When eukaryotes evolved
What are 5 examples of gram-positive bacteria?
- Actinomycetes
- Bacillus anthracis
- Clostrdium botulinum
- Staphylococcus, Streptococcus
- Mycoplasms
What is the smallest organism?
fibroblast
Some archaea are ________
extremophiles
What are extremophiles?
archaea that can live in extreme enviornments
Where do extreme halophiles live?
highly saline environments
Where do extreme thermophiles live?
in very hot environments
What are methanogens?
- make methane as waste product from CO2
- keep earth heated or unheated
What are 2 qualities of methanogens?
- live in swamps and marches
2. strict anaerobes
Prokaryotes play a major role in the recycling of _______
chemical elements between living and nonliving components of ecosystems
What do decomposers do?
break down dead organisms and waste products
Which prokaryotes function as decomposers?
chemoheterotrophic prokaryotes
Prokaryotes can sometimes increase the availability of ____, _____, and _____ for plant growth
-nitrogen, phosphorus, potassium
What is symbiosis?
- an ecological relationship
- two species live in close contact (host, symbiont)
What happens in mutualism?
both symbiotic organisms benefit
What happens in commensalism?
- one organism benefits
- neither harming nor helping the other
What happens in parasitism ?
organism (parasite) harms but does not kill its host
What are pathogens?
parasites that cause disease
How do pathogenic prokaryotes typically cause disease?
-releasing exotoxins or endotoxisn
What are exotoxins?
- secreted
- cause disease even if prokaryotes that produce them are not present
What are endotoxins?
-released only when bacteria die, and cell walls break down
What can horizontal gene transfer spread?
genes associated with virulence EX: E. Coli
What kind of important advances have experiments using prokaryotes led to?
DNA technology
EX: E. coli used in gene cloning
EX: agrobacterium tumefaciens used to produce transgenic plants
-plastics
what is bioremediation?
use of organisms to remove pollutants form teh environment
What are 3 things that bacteria can be engineered to produce?
- vitamins
- antibiotics
- hormones
