BIO102: Chapter 27: Archaea and Bacteria
archaea have distinctive membrane phospholipids that are formed with _______ _______, while ester bonds make up the membrane phospholipids of bacteria and eukaryotes
- ether bonds
describe episilon proteobacteria
- examples include helicobacter pylori
describe delta proteobacteria
- examples include myxobacteria and bdellovibrios
how do aerotolerant anaerobes get their energy
- fermentation - anaerobic respiration
what are some examples of obligate anaerobes
- firmicutes genus Clostridium
prokaryotic species differ in number and location of ________. how can these structures occur
- flagella - as singly, or in tufts at one pole or may emerge from around the cell
what is a pro of biofilms
- forming them helps microbes remain in favorable locations for growth
define vertical evolution
- gene transfer occurs often from parent to progeny *no interference*
many bacteria exude a coat of slimy mucilage called.....
- glycocalyx, capsule, or extracellular polymeric substance (EPS)
bacteria having chemically different walls are called ______ _______ or ________ ________ after the staining process used to distinguish them
- gram-positive - gram-negative
what are some characteristics of the phyla Actinobacteria
- gram-positive bacteria producing branched filaments - many form spores - notable antibiotic producers(over 500 different antibioticsc known from this group) - some fix nitrogen in association with plants
how have gram negative bacteria adapted to the presence of an outer envelope
- has several types of protein systems that function in secretion
what other roles does mucilage play a part in
- holding cells together closely enough for chemical communication and DNA exchange to occur - helping aquatic species to float in water - binding mineral nutrients - repelling attack
what are some characteristics of Lokiarchaeota
- identified from deep ocean samples - closely related to eukaryotes
what are the enviromental and medical importance of biofilms
- in aquatic and terrestrial environments they stabalize and enrich sand and soil surfaces - important in formation of mineral deposits - dental plaque is an example of bad biofilm - can develop in industrial pipelines where it can corrode metal surfaces
what are some characteristics of Crenarchaeota
- includes organisms that live in extremely cold or hot habitats - some are widespread in aquatic and terrestrial habitats
what are some characteristics of the phyla Bacteroidetes
- includes representatives of diverse metabolism types, *(some are common in the human intestinal tract and others are primarily aquatic)*
what kind of effect do archaea's and bacteria's metabolic processes have on a global scale
- influence earth's climate - atmospheres - soils - water quality - human health and technology
how are endospores produced
- inside bacterial cells by the enclosure of DNA and other materials within a tough coat, and then are released when the enclosing cell dies and breaks down.
what are some characteristics of the phyla Chloroflexi
- known as the green nonsulfur bacteria - conduct photosynthesis without releasing oxygen
define akinetes
- large, food-filled cells that can survive in winter - produced by aquatic filamentous cyanobacteria
the __________ _________ outer envelope of gram negative bacteria helps them to resist the entry of some antibiotics but on the verse impedes secretions of _______from bacterial cells into the environment, a process that normally allows cells to communicate with each other
- lipopolysaccharide rich - proteins
what does Borrelia burgdorferi cause
- lyme disease
in other bacteria, plasma membrane ingrowth has generated additional intriguing adaptations like....
- magnetosomes - nucleus like bodies/bacterial organelles
in what bacteria do magnetosomes occur in
- magnetospirillum and its related genera
what are the functions of a cell wall
- maintain cell shape and help protect against attack by viruses or predatory bacteria - help microbes avoid lysing in hypotonic conditions
what are some characteristics of the phyla Spirochaetes
- motile bacteria having distinctive corkscrew shapes with flagella held close to the body - include pathogens Treponema pallidum(agent of syphilis) and Borrelia burgdorferi(causes lyme disease)
some cyanobacteria display ____________, like cellular attachment, specialized cells, intercellular chemical communication, and apoptosis
- multicellularity
define chemoheterotrophs
- must obtain organic molecules for both energy and as a carbon source
what are some characteristics of the phyla Chlamydiae
- notably tiny, obligate intracellular parasites - some cause eye disease in newborns or sexually transmitted diseases
what do the domains Archaea and Bacteria consist of?
- of microorganisms whose cells have a prokaryotic structure - ex: lack nuclei with porous envelopes and other structures that eukaryotes have
define autotrophs
- organisms that are able to produce all or most of their own organic compounds from inorganic sources
define extremophiles
- organisms that occur primarily in extreme habitats
define heterotroph
- organisms that require at least one organic compound and often more from their environment
what are some characteristics of the phyla Cyanobacteria
- oxygen producing photosynthetic bacteria (some capable of anoxygenic photosynthesis) - photosynthetic pigments include chlorophyll a and phycobilins - can occur as unicells, colonies, unbranched filaments, and branched filaments - in waters having excess nutrients, blooms may be produced and may release toxins harmful to the health of humans and wild domesticated animals
the domain archaea and bacteria are termed a _______ group
- paraphyletic
what are injectosomes
- pathogenic bacteria have developed needle-like systems made of components found in flagella that inject proteins into animal or plant cells as part of the infection process *type III secretion systems*
bacterial cell walls occur in two major forms that differ in ________ ______, _________ ________, and response to __________
- peptidoglycan thickness - staining properties - antibiotics
the outer envelope of gram negative bacteria is a _________ ________, but distinct from the plasma membrane
- phospholipid bilayer
what two categories can autotrophs be broken down into
- photoautotroph - chemoautotroph
what are two subcategories of heterotrophs
- photoheterotrophs - chemoheterotrophs
define obligate anaerobes
- poisoned by molecular oxygen
what are some characteristics of Korarchaeota
- primarily known from DNA sequences found in samples from hotsprings
what key ecological roles do bacteria and archaea play
- producing and breaking down organic carbon - acting as beneficial symbionts in plants and animals - act as disease agents
some archael cells lack cell walls most possess a wall composed of _______
- protein
give some examples of organisms that do nitrogen fixation
- proteobacteria of the genus Rhizobium
what are the categories of extremophiles
- psychrophiles - thermophiles - radioresistant microbes - alkaliphiles - acidophiles - halophiles - xerophiles - barophiles - endoliths
what are some characteristics of the phyla Planctomycetes
- reproduce by budding rather than binary fission - cell wall lacks peptidoglycan - cytoplasm may contain nucleus-like bodies - endocytosis may occur
define obligate aerobes
- require oxygen gas (molecular oxygen) in order to survive
what are some characteristics of ether bonds
- resistant to damage by heat and other extreme conditions
describe archaeal flagella
- rotate but are much thinner than bacterial flagella - powered by hydrolysis of ATP
diverse archaea occupy habitats with very high _______ ________, ________, _________ _________ or __________ that would kill most bacteria and eukaryotes
- salt content - acidity - methane levels - temperatures
what is another name for decomposers
- saprobes
describe gamma proteobacteria
- some examples include neisseria gonorrhoeae, vibrio cholerae, salmonella enterica, and escherichia coli
how is FtsZ used in binary fission
- squeezes dividing cells into two progeny cells
where do methanogens live
- swampy wetlands - deep sea habitats - subsurface arctic deposits
what research is behind the human microbiome
- that humans have inherited gut microbes from primates through extensive horizontal gene transfer
describe beta proteobacteria
- the genus is nitrosomonas, a soil inhabitant important in the global nitrogen cycle is a prime example
what does the endosymbiosis theory propose
- the mitochondria and chloroplasts of eukaryotic cells originated from alpha proteobacteria and cyanobacteria respectively by endosymbiosis. *in this case, endosymbiosis resulted in the horizontal transfer of many genes from bacterial genomes to eukaryotic nuclei* - chloroplasts and mitochondria cannot reproduce outside the host eukaryotic cells
what do archaea help biologist understand....
- the origin of life - origin of eukaryotes - how life on earth has evolved in extreme environments - what kinds of extraterrestrial life might exist
what does the koch postulates states and what is the reason for its use
- the presence of suspected pathogen must correlate with occurrence of symptoms - pathogen must be isolated from infected cell and grown in pure culture if possible - cells from pure culture show cause disease when inoculated into a healthy host - same pathogen show be isolatable from the second infected host *used to determine whether a particular organism causes a specific disease*
define horizontal gene transfer
- the process in which an organisms receives genetic material from another organism without being the offspring of that organism
define nitrogen fixation
- the removal of nitrogen from the gaseous phase is called fixation
if a bacteria is gram-positive they will have walls that are relatively _________ _______ __________. what phyla(s) of bacteria are gram positive
- thick peptidoglycan layer - firmicutes and actinobacteria
if a bacteria is gram-negative they will have walls with a ________ ______ of ________ enclosed by a thin, outer envelope whose outer leaflet is rich in ___________
- thinner layer of peptidoglycan - lipopolysaccharides
what is an example of a facultative anaerobe
- thiomargarita namibiensis
what are magnetosomes
- tiny crystals of an iron mineral known as magnetite, each surrounded by a membrane - help bacteria orient themselves in space and thereby locate the submerged, low oxygen habitats that they prefer
horizontal gene transfer can occur between two different bacterial species via _________, ___________, and ____________
- transduction - transformation - conjugation
what is another way to detect and count prokaryotic cells
- treat samples with a stain that binds bacterial DNA causing cells to glow brightly when illuminated with UV light *called the fluoresence method*
define chemoautotroph
- use energy obtained by chemical modification of inorganic compounds to synthesize organic compounds - ex: nitrification, oxidation of sulfur, iron or hydrogen
define photoautotroph
- use light as a source of energy for the synthesis of organic compounds from CO2 and H2O or from H2S
describe bioremediation
- used to reduce levels of harmful materials in the environment
what are some characteristics of the phyla proteobacteria
- very large group of gram-negative bacteria(collectively having high metabolic diversity) - include many species important to medicine, agriculuture and industry -
what are some characteristics of Thaumarchaeota
- widespread in terrestrial and aquatic environments - has species that oxidize ammonia (important in global nitrogen cycling)
what are some examples of bacteria with injectosomes that allow them to attack human cells
- yersinia pestis (agent of bubonic plague) - salmonella enterica (food poisoning called salmonellosis) - burkholderia pseudomallei (cause of meliodosis)
what does Treponema pallidum cause
agent of syphilis
what are methanogens
anaerobic archaea that convert CO2, methyl groups or acetate to methane and release methane from their cells into the atmosphere
the chloroplasts of eukaryotic algae and plants were derived from _____________
cyanobacteria
what is the only bacteria known to generate oxygen as a product of photosynthesis
cyanobacteria
_________ __________ determine cell shape
cytoskeletal proteins
what kind of movement does a pili provide
directional movement toward food materials
what are aerotolerant anaerobes
do not use oxygen but are not poisoned by it either
________ can remain alive, although in a dormant state for long periods of time and reactivate when conditions are suitable
endospores
horizontal gene transfer can also occur via _____________
endosymbiosis
organisms classified in the domain archaea share a number of features with those classified in ______________, suggesting a common ancestry
eukarya
small cell size limits the amount of materials that can be stored within cells but will allow ______ cell division
faster
define halophiles
species able to grow in higher than usual salt concentrations
many bacteria form __________ __________ with eukaryotes and are thus of concern in medicine and agriculture
symbiotic associations
what is Mycobacterium tuberculosis in reference to humans
the agent of tuberculosis
define endosymbiosis
the process in which one species lives in the body of another species
define horizontal gene transfer
the transfer of genes between different species
some other gram-negative bacteria pathogens used a _________ _________ secretion system to deliver toxins or DNA into cells
type IV
what way do bacteria and archaeal species reproduce
via binary fission
what is anoxygenic photosynthesis
when an organism photosynthesizes but no oxygen is released
what are some characteristics of euryarchaeota
- early diverging euryarchaeota include some hyperthermophiles, diverse methane producers, and extreme halophiles
what are some examples of Proteobacteria
- Agrobacterium tumifaciens - Escherichia coli - Haemophilus influenzae
the phyla's ________ and _________ are particulary diverse and relevant to eukaryotic cell evolution, global ecology and human affairs
- Cyanobacteria - Proteobacteria
what are the three domains of life
- Eukarya - Archaea - Bacteria
name 10 major phyla's of the domain bacteria
- Firmicutes - Bacteroidetes - Chlamydiae - Planctomycetes - Spirochaetes - Actinobacteria - Chloroflexi - Deinococcus and Thermus - Cyanobacteria - Proteobacteria
name some phyla of the domain archaea
- Lokiarchaeota - Korarchaeota - Thaumarchaeota - Crenarchaeota - Euryarchaeota
what is an example of the phyla Actinobacteria
- Mycobacterium tuberculosis
what is myxococcus xanthus
- a gram negative bacterium that is able to glide across surfaces, forming swarms of thousands of cells - this behavior aids feeding by concentrating digestive enzymes secreted by the bacteria and when food is scarce the swarms form tiny tree-shaped structures from which tough spores disperse, by this means cells move to new, food rich places - part of the phyla Proteobacteria
what are some characteristics of a methanopyrus
- a methane producer - an example of an hyperthermophile( a subcategory of extremophile) - grows best at deep sea vents (98 degrees celsius) - cannot grow in temperature less than 84 degress celsius
define quorum sensing
- a process that fosters biofilm formation - individual microbes secrete small molecules having the potential to influence the behavior of nearby microbes, if enough present signalling molecules build up to cause a collective behavior
what are photoheterotrophs
- able to use light energy to generate ATP but they must take in organic compounds from the environment as a source of carbon
what does neisseria gonorrhoeae cause
- agent of disease gonorrhea
describe biofilms
- aggregations of microorganisms that secrete adhesive mucilage, thereby gluing themselves to surfaces
genera of the phyla proteobacteria can be broken down into five major subgroups, what are they?
- alpha - beta - gamma - delta - epsilon
define symbiosis
- an organism that lives in close association with one or more other organisms
describe alpha proteobacteria
- ancestors of mitochondria - Rhizobium and other related genera of this category form mutually beneficial associations with the roots of legume plants - agrobacterium
what does the domain Eukarya consist of
- animals, plants, fungi, and protists
what is an example of chemoautotroph
- archaea of the genus sulfolobus
what are some characteristics of the phyla Deinococcus and Thermus
- are extremophiles - the genus Deinococcus is known for high resistance to ionizing radiation and the genus thermus means inhabits hot springs
cyanobacteria display the greatest body of diversity found among the bacterial phyla, name some forms they occur in.
- as single cells called unicells - as colonies of cells held together by thick, gluey substance called mucilage - form filaments of cells that are attached end-to-end (including filaments that branch)
what is an example of photoheterotrophs
- bacteria in the phyla chloroflexi
describe Gemmata obscuriglobus
- bacteria with nucleus like bodies/bacterial organelles
why are cyanobacteria named as such
- because they have photosynthetic pigments called phycobilins that help chlorophyll absorb light energy giving cyanobacteria a blue-green hue
describe bacterial flagellum
- built of about 30 proteins - lack plasma membrane covering - internal cytoskeleton of microtubules made of tubulin - lack motor protein dynein - spin, propelled by molecular machines composed of a filament, hook and motor - powered by the movement of hydrogen ions (electron transport chain)
how do pathogenic bacteria attack cells
- by binding to the surface of healthy cells and injecting substances that help them utilize cellular components
describe what bacterial organelle/nucleus like body is?
- can isolate DNA in a simplistic membrane
define facultative anaerobes
- can use oxygen via aerobic respiration, obtain energy via anaerobic fermentation, or use inorganic chemical reactions to obtain energy
what does agrobacterium tumifaciens do
- causes destructive cancer-like tumors called galls to develop on susceptible plants - caused by injecting its DNA into the plant cells
what does helicobacter pylori do?
- causes stomach ulcers
describe methotrophs
- certain bacteria that consume methane, thereby reducing its concentration in the atmosphere
what does vibrio cholerae cause
- cholera epidemics through contaminated water
what are the five common shapes that prokaryotic cells can occur in?
- cocci (spheres) - bacilli (elongated rods) - vibrios (comma shaped cells) - spirochaetes (spiral shaped cells that are either flexible) - spirilli (spiral shaped cells that are rigid)
what is peptidoglycan
- composed of carbohydrates that are cross-linked by peptides
describe mucilage
- composed of hydrated polysaccharides and proteins as well as lipids and nucleic acids
what is an example of photoautotrophs
- cyanobacteria
give some examples of producers
- cyanobacteria - autotrophic bacteria
what are some phyla(s) of bacteria that are gram negative
- cyanobacteria - proteobacteria
what are some characteristics of the phyla Firmicutes
- diverse gram-positive bacteria, some of which produce endospores - an example is the disease causing Clostridium difficile
many filamentous species produce specialized cells like....
- dormant akinetes and heterocytes in which nitrogen fixation occurs
what do myxobacteria and bdellovibrios proteobacteria do
- drill through the cells walls of other bacteria in order to consume them
bacterial binary fission generally requires a protein known as _________, which is related to the tubulin that make up eukaryotic microtubules
FtsZ
many bacteria are able to break down __________ for use as a source of organic carbon
antibiotics
horizontal gene transfer is common among _________ and _________
archaea and bacteria
what domain(s) are the most abundants and smallest known cells found on earth
archaea and bacteria
______ _______ is the basis of a widely used method for detecting and counting bacteria in food, water samples, or patients' body fluids
binary fission
a ________ helps some disease bacteria evade the defensive system of their host
capsule
most prokaryotic cells have a _______ _______
cell wall
______ _________ is an important component of bacterial function in nature
cellular shape
horizontal gene transfer affects __________ __________
genetic diversity
the ability to produce endospores allows some ______ _______ bacteria in the phylum firmicutes to cause serious diseases
gram positive
many cyanobacteria generate low oxygen conditions in specialized cells known as ________, allowing nitrogen fixation to occur in these cells
heterocytes
archaea use __________ chains instead of fatty acid chains in their membranes
isoprene
oxygen can poison nitrogenase, so most nitrogen fixers conduct nitrogen fixation in _____ ______ _______
low oxygen conditions
what is meant by gram negative bacteria?
mean they have a thinner layer of peptidoglycan and won't stain as much
what is meant by gram positive bacteria?
means it has a thicker layer of peptidoglycan thus penicillin(or any strong antibiotic) can kill it more than it could a gram negative.
define pathogens
microorganisms that cause disease in one or more types of host organism
although some members of domain bacteria live in extreme conditions, most favor ___________ conditions
moderate
if symbiotic association is beneficial to both partners the interaction is known as __________
mutualism
most prokaryotes are _______ _______
obligate aerobes
define paraphyletic group
one that does not include all the descendants of a single common ancestor
define acidophiles
organisms capable of surviving in highly acidic environments (pH of below 2)
define radioresistant microbes
organisms that can survive extreme exposure to radiation
define barophiles
organisms that can survive in highly pressurized environments
define xerophiles
organisms that can survive in very dry environments
define alkaliphiles
organisms with the ability to survive in environments capable of neutralizing strong acids (base environments with a pH from 9-11)
define psychrophiles
organisms with the ability to survive in extreme cold temperatures (starting below -4 degrees farenheit)
define thermophiles
organisms with the ability to survive in extreme heat temperature (above 140 degrees farenheit)
define endoliths
organisms with the ability to survive within solid rocks or deep in the earths' crust
if one partner in symbiosis benefits at the expense of the other the association is termed ______
parasitism
bacterial cells wall are made of ____________
peptidoglycan
_________ ________ ________ coat some bacterial filaments helping to prevent UV damage
pigmented slime sheaths
what do phycobilins give to cells
pigments them a blue-green color
some prokaryotic species have ______
pili
archaea and eukarya share more than 30 __________ _________ that are not present in bacteria
ribosomal proteins