Bacteria and Archaea

direct sequencing

A new technique for documenting the presence of bacteria and archaea that have never been seen because they cannot be grown in pure culture. Specific genes fromt he sample are isolated using PCR. these genes are sequences and compared with sequences in existing databases. If the sequences are markedly different, then the sample probably contains previously undiscovered organisms.

lateral gene transfer

A process in which organisms that reproduce asexually pass genes from one individual to another, or even from individuals of one species to another. 1) transformation; what happens when bacteria takes up DNA from the environment.

extremophiles

Bacteria or archaea that live in high-salt, high-temperature, low-temperature, or high-pressure habitats. Understanding them may help explain how life on Earth began. Astrobiologists use them as model organisms in the search for extraterrestrial life. Enzymes that function at extreme temperatures and pressures are useful in industrial processes.

eukarya

Domain of all organisms whose cells have nuclei, including protists, plants, fungi, and animals.

bacteria

Domain of unicellular prokaryotes that have cell walls containing peptidoglycan.

proteobacteria

Forms five major subgroups and are very diverse in morphology and metabolism. Alpha-proteobacteria are the organisms that we know evolved to become mitochondria. Thiomargarita namibiensis is sulfur-metabolizing gamma proteobacteria and is one of the largest known bacteria (it is macroscopic). Some proteobacteria can form colonies, which can produce a structure called a fruiting body. Pathogenic proteobacteria cause Legionnaire's disease, cholera, dysentery, and gonorrhea.

obligate

HAS to infect

archaea

Live in virtually every habitat, including extreme environments; However, there are no known parasitic archaea (one recently discovered achaean causes periodontitis). Domain Archaea is composed of at least two major lineages. The domain was discovered so recently that major groups are still being discovered and described; two additional lineages may exist (Korarheota and Nanoarcheota). Most often categorized as extremophiles.

biogeochemical cycle

Process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another. Some aspect of life on earth in the nonliving atmosphere

anaerobic respiration

Respiration that does not require oxygen

aerobic respiration

Respiration that requires oxygen

heterocysts

Some cyanobacteria have specialized N-fixing cells called heterocysts. fixes nitrogen.

fruiting body

Some proteobacteria can form colonies, which can produces these structures. The reproductive structure of a fungus that contains many hyphae and produces spores.

cyanobacteria

These were formerly known as "blue-green algae." They are found as independent cells, chains, or colonies. All perform oxygenic photosynthesis; they produce oxygen, nitrogen, and organic compounds that feed other organisms in aquatic environments. Some have specialized N-fixing cells called heterocysts.

Koch's postulates

This confirms a causative link between a specific infectious disease and a specific microbe. The microbe must be present in individuals suffering from the disease and absent from healthy individuals. The organism must be isolated and grown in a pure culture away from the host organism. If organisms from the pure culture are injected into a healthy experimental animal, the disease symptoms should appear. The organism should be isolated from the diseased experimental animal, again grown in pure culture, and demonstrated to be the same as the original organism.

universal tree (tree of life)

This shows that domain Bacteria was the first lineage to diverge from the common ancestor of all living organisms. It also shows that the archaea and Eukarya are more closely related to each other than they are to the bacteria.

spirochaeles (spirochetes)

are distinguished by their corkscrew shape and unusual flagella. most spirochetes produce ATP via fermentation. these bacteria produce ATP via fermentation. these bacteria are very common in aquatic habitats. spirochetes cause the diseases syphilis and lyme disease.

actinobacteria

are gram positive and shape varies from rods to filaments. many of the soil-dwelling species are found as chains of cells that form extensive branching filaments called mycelia. many species are heterotrophs. some species live as decomposers in soil; some live in association with plant roots and fix nitrogen. Tuberculosis and leprosy are caused by members of this group. Species from genus Streptomyces produce over 500 distinct antibiotics. They are group that are have fungus like growth habits.

morphological diversity

bacteria and archaea show extensive morphological diversity in terms of size, shape, and motility.

pathogenic

bacteria that cause disease. only a tiny fraction of the bacterial species living on and in the human body are pathogenic. pathogenic bacteria come from many lineages.

gram positive

bacteria that has a thick cell wall containing an extensive amount of carbohydrates called peptidoglycan. very think layer so they can hold onto the stain better- looks purple

transformation

bacteria will take up genes and make it a part of their own genome.

crenarchaeota

can be shaped like filaments, rods, discs, or spheres. They are metabolically diverse, although some make ATP only through fermentation. They are the only life-forms present in certain extreme environments, such as high-pressure, very hot, cold, or acidic environments.

gram-negative

cells that have a cell wall with two components, a thin layer containing peptidoglycan and an outer phospholipid bilayer. dont retai the stain well so they look pink.

morphology

extreme diversity in this and metabolism allows bacteria and archaea to live in a wide array of environments

metabolism

extreme diversity in this and morphology allows bacteria and archaea to live in a wide array of environments

peptidoglycan

gram positive cells have a cell wall containing an extensive amount of this carbohydrate.

enrichment cultures

growing them in cultures of growth media to form colonies. This is one way that we are able to detect bacteria.

facultative

it can infect but it doest have to

ecosystem services

living things in the ecosystem do things that that benefit humans. Important environmental benefits, such as clean air to breathe, clean water to drink, and fertile soil in which to grow crops, that ecosystems provide

mycelia

many of the soil dwelling species are found as chains of cells that form extensive branching filaments

endosymbionts

necessary relationship where they have to infect the cells of a living things. they live as parasites inside animal cells and get almost all of their nutrition from their hosts.

methanogens

one of the many shapes of a euryarochaeota. This controbutes about 2 billion tons of methane to the atmosphere each year.

rhizobial bacteria

root microbacteria, fixing nitrogen

antibiotics

the discovery of this in 1928 and their widespread use starting in the 1940s allowed physicians to effectively combat most bacterial infections. Overuse of antibiotics since the late twentieth century has lead to antibiotic-resistant strains of bacteria.

germ theory of disease

the experiments of Robert Koch in the late 1800s became the basis for this, which holds that infectious diseases are caused by bacteria ad viruses. Koch postulates confirm a causative link between a specific infectious disease and a specific microbe.

nitrogen fixation

the only organisms capable of converting molecular nitrogen to ammonia are specific bacteria.

bioremediation

the use of bacteria and archaea to degrade pollutants. metabolic diversity that the bacteria has allows for this to happen. Metabolic diversity that the bacteria has allows for this to happen.

firmicutes

these are gram positive and most are rod shaped or spherical. they are metabolically diverse, species in this group are important components of soil, some species in this group cause diseases, yet we use some to ferment milk into yogurt. They are the most ancestral bacteria, most like the original ancestor.

chlamydiae

these are spherical and very tiny. they are endosymbionts- they live as parasites inside animal cells and get almost all of their nutrition from their hosts.

gram stain

this is a treatment with a dye that distinguishes two general types of cell wall.

euryarchaeota

this is an archaea. they live in every conceivable habitat, including high-salt, high-pH, and low-pH environments. they include the methanogens, whihc contribute about 2 million tons of ethan to the atmosphere each year.