Section 24.2 (Exam 1) Flashcards
Prokaryote Diversity Reflects the Ancient Origins of Life
What are the 8 groups of bacteria that have received the most study?
Hadobacteria, Hyperthermophilic bacteria, Firmicutes, Actinobacteria, Cyanobacteria, Spirochete, Chlamydias, Proteobacteria
Define extremophiles.
Extremophiles thrive in extreme conditions that would kill most other organisms.
Hadobacteria are _________. Name some examples of hadobacteria.
Thermophiles; Deinococcus and Thermus aquaticus
Describe some characteristics of the hadobacteria Deinococcus
Resistant to radiation, consume nuclear waste, survive in both extreme cold and heat
Describe some characteristics of the hadobacteria Thermus aquaticus.
found in a hot spring, source of thermally stable DNA polymerase, critical for development of PCR (Polymerase chain reaction, used to amplify DNA sequences)
What is DNA polymerase?
an enzyme that copies DNA strands
Hyperthermophilic bacteria are extreme thermophiles. They live in hot springs, near volcanic vents, deep oil deposits, and other hot environments. Name two hyperthermophilic bacteria.
Aquifex and Thermotoga
Where do Aquifex live?
Volcanic vents
Where do Thermotoga live?
Oil reserves
What does it mean to be low or high-GC?
Low-GC means a low ratio of G-C to A-T base pairs in DNA. High-GC means more G-C than A-T.
Firmicutes are low or high GC? Are they Gram-positive or negative?
low-GC; Gram-positive
Some firmicutes produce ___________, heat resistant resting structures with tough cell walls and spore coats that can survive harsh conditions because they are dormant.
endospores
Name some firmicutes.
Clostridium, Bacillus, Staphylococcus, Streptococcus, and Mycoplasmas
What can Clostridium (a type of firmicute) cause?
botulism and tetanus
When do bacillus anthracis (anthrax, also a type of firmicute) endospores activate?
When they sense the presence of macrophages in mammal blood.
Staphylococcus bacteria (a type of firmicute) can cause what kinds of problems?
Boils and skin problems.
What does Staphylococcus aureus cause?
Skin diseases, respiratory infections, and intestinal infections.
What are some characteristics of mycoplasmas?
They have no cell wall, they are extremely small, and they have less than half as much DNA as other prokaryotes.
Actinobacteria are low or high GC? Are they Gram-positive or negative?
high-GC; Gram-positive
What are some characteristics of actinobacteria?
Elaborately branching filaments, some reproduce by forming chains of spores at filament tips, most antibiotics come from actinobacteria
What are some examples of actinobacteria?
Mycobacterium tuberculosis and Streptomyces (produce streptomycin).
What are some characteristics of cyanobacteria?
blue-green, photosynthetic, use chlorophyll a, many species fix nitrogen, have internal membrane system
What are photosynthetic lamellae?
The internal membrane system of cyanobacteria that performs photosynthesis.
What are eukaryote chloroplasts derived from?
Endosymbiotic cyanobacteria
Are cyanobacteria free-living or colonial?
They can be either!
Some colonies of cyanobacteria differentiate. What can they differentiate into?
Vegetative cells, spores, or heterocysts
What do vegetative cells do?
Perform photosynthetic functions.
What is the purpose of spores in cyanobacteria?
To endure harsh conditions and environments. The cells can lie dormant, and activate whenever they reach an environment they can survive in.
What are heterocysts and what do they do?
Heterocysts are specialized cyanobacteria cells that can fix nitrogen from nitrogen gas (N2) into a usable form like ammonia (NH3)
Name some characteristics of spirochetes.
Gram-negative, motile, unique axial filaments (modified flagella) resulting in corkscrew-like movement, many human parasites and pathogens
Name some types of spirochetes.
Syphillis and Borrelia burgdorferi (Lyme disease)
Name some characteristics of chlamydia.
Very small, Gram-negative cocci, pathogens, take up ATP from host using translocase, complex life cycle with two forms
What are the two forms of the complex life cycle of chlamydia, and how does chlamydia cycle between them?
Elementary bodies grow into reticulate bodies, which multiply into elementary bodies.
What problems can chlamydias cause?
They are pathogens that can cause eye infections, STDs, and some forms of pneumonia.
Proteobacteria is the ___________ group of bacteria, meaning high diversity,
largest
Eukaryote mitochondria are derived from an endosymbiotic _____________.
proteobacterium
What are some examples of proteobacteria?
E. coli, Rhizobium (rhizobacteria, nitrogen-fixers), Yersinia pestis, salmonella typhimurium, Vibrio cholerae, agrobacterium tumefaciens
What is Yersinia pestis, a proteobacterium, commonly known as?
bubonic plague
What is salmonella typhimurium, a proteobacterium, commonly known as?
Salmonella, a type of gastrointestinal disease
What is Vibrio cholerae, a proteobacterium, commonly known as?
Cholera
Some proteobacterium do photosynthesis using __________________ as an electron donor, producing sulfur as a byproduct.
hydrogen sulfide (H2S)
Agrobacterium tumefaciens causes a type of plant tumor called ____________. It also has a plasmid used as a vector in recombinant DNA technology.
Crown gall
Archaea being a separate domain was originally based on _________________.
rRNA gene sequencing
Archaea are famous for living in __________________, such as high salinity, high temperatures, high or low pH, and low oxygen.
extreme conditions
Not all Archaea are extremophiles. True or False?
True
Archaea do not have _______________ in their cell walls, but Bacteria do.
peptidoglycan
Bacterial and eukaryotic membrane lipids have fatty acids connected to glycerol by ________ linkages.
ester
Archaea membrane lipids have fatty acids linked to glycerol by _________ linkages.
ether
Archaea have lipids with _______________________ chains.
branched hydrocarbon
Like bacteria and eukaryotes, some archaea have cell membranes that consist of a _________________.
lipid bilayer
Unlike bacteria and eukaryotes, some archaea have long-chain hydrocarbons that span the cell membrane, which is formed by a ________________.
lipid monolayer
What are the 5 lineages of prokaryote archaea?
Euyarchaeota, Crenarchaeota, Thaumarchaeota, Korarchaeota, Lokiarchaeota
What are some types of euryarchaeotes?
Some are methanogens and some are halophiles.
What are methanogens?
They produce methane by reducing CO2, and are obligate anaerobes. They live in the guts of grazing mammals (cows), termites, and cockroaches.
What are obligate anaerobes?
They can only survive without oxygen. Thus, the anaerobic aspect of them is obligatory.
What are extreme halophiles?
They love salt, and have pink carotenoid pigments. They also live in extremely alkaline (basic) environments.
Some halophiles have a unique system for using light to form ATP using the light-absorbing molecule ________________.
bacteriorhodopsin
Thermoplasma is a type of euryarchaeote. Name some of its characteristics.
Thermophilic and acidophilic, aerobic metabolism, no cell wall, lives in coal deposits, smallest genome of archaea (like mycoplasma)
Most crenarchaeotes are _____________________.
thermophilic, acidophilic, or both
Example of a crenarchaeote that lives in hot sulfur springs that have a pH of 2-3.
Sulfolobus
Korarchaeotes and thaumarchaeotes are only known from DNA isolated directly from __________________. None of these have been grown in pure culture.
hot environments
Thaumarchaeotes oxidize __________ and may play an important role in the nitrogen cycle.
ammonia (NH3)
Lokiarchaeotes were discovered in 2015 by sequencing environmental samples from a hydrothermal vent. They are very similar, and the closest known prokaryotic relative of _____________.
eukaryotes
Which firmicutes produce endospores?
Bacillus and Clostridium
