Microbiology chapter 27 & 28

Eutrophication

An increase in nutrient levels that stimulates the growth of a limited number of organisms, thereby disturbing the ecology of these aquatic ecosystems.

Parasite

An organism that feeds on a living host

epibiotic predators

Attach to their prey organisms surface Ex. Attach to the outer membrane and secrete degradative enzymes that result in lysis and the release of the prey's cytoplasmic contents.

Mineralization

Describes the decomposition of organic matter to simpler, inorganic compounds (CO2, NH2, CH4, H2)

competitive exclusion principle

Ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time

dissimilatory nitrate reduction

When respired, the nitrogen is not incorporated into cellular material, so this is called _____________

dissimilatory sulfate reduction

When sulfate diffuses into anoxic habitats, it provides an opportunity for microbial ___________________

endosymbiont

a cell that lives within a host cell

Amensalism

a relationship in which one organism is harmed and the other is unaffected

Mutualist

a type of symbiosis in which both organisms or populations are benefited

Zooxanthellae

a yellowish-brown symbiotic dinoflagellate present in large numbers in the cytoplasm of many marine invertebrates.

Environmental microbiology

branch of microbiology studying the role of microorganisms in soils, water, and other habitats

biogeochemical cycling

cycling of nutrients from abiotic to biotic sources through biological, geological, and chemical processes.

greenhouse gases

gases in the atmosphere that trap energy

Simplified Nitrogen Cycle

(The goal is to get usable nitrogen from the air into the soil so it can be absorbed by plants and enter the food chain.)

Ectosymbiont

organism located on surface of another organism (usually larger)

genomic reduction

- outcome of long-term parasitic relationship -parasite loses unused genomic information

anammox reaction

-anaerobic reaction performed by chemolithotrophs -ammonium ion (NH4+) serves as the electron donor and nitrite (NO2-) as the terminal electron acceptor; it is reduced to nitrogen gas (N2) -shortcut to N2, proceeding directly from ammonium to nitrite, without having to cycle first through nitrate

The CO2 is carried to the endosymbionts in three ways:

1. Freely in bloodstream 2. Bound to hemoglobin 3. As organic acids such as Malays and succinate

Carbon cycle influenced by 4 other factors

1. Oxidation-reduction potential 2. Availability of competing nutrients 3. Abiotic conditions such as pH, temperature, O2, and osmotic conditions 4. The microbial community present

Symbiosis

A close relationship between two species that benefits at least one of the species.

The initial product of nitrogen fixation is

Ammonia

When organic molecules are mineralized they release nitrogen in the chemical form of ________

Ammonium

redox potential

A measure of the tendency of a given redox pair to donate or accept electrons.

coral bleaching

A phenomenon in which algae inside corals die, causing the corals to turn white. Loss of either the photosynthetic pigments from the zooxanthellae or the complete expulsion of the dinoflagellates from the coral.

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

Parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

assimilatory nitrate reduction

Can be reduced and incorporated into microbial and plant cell biomass in a process known as ___________

Comammox

Complete ammonia oxidation

Denitrification

Conversion of nitrates into nitrogen gas

Which molecules represent reduced forms of carbon?

Glucose, glycine, methane

interspecies hydrogen transfer

H2 production by one partner is linked to H2 consumption by the other

Endobiotic predators

Invade the victims cytoplasm or periplasm where they consume the contents to obtain the energy and precursors needed for cell division.

Biomagnification

Methylated Mercury forms are volatile and lipid soluble, and Mercury concentrations increase with each link of the food web in a process known as ________________

The conversion of gaseous nitrogen to its organic forms is referred to as

Nitrogen fixation

Mercury Cycle

Nowadays, human activities are the most important source of mercury to the environment. Because mercury is taken up by plants and animals and stored in their tissues, they play an important role in the cycling of mercury.

Immobilization

Nutrients converted into biomass become temporarily unavailable for nutrient cycling

How would the process by which organic matter is converted into carbon dioxide be described?

Oxidative

What kind of process is sulfur oxidation?

Oxidative

Coevolution

Process by which two species evolve in response to changes in each other

nitrogen fixation

Process of converting nitrogen gas into ammonia

What kind of process is denitrification?

Reductive

What kind of process is the conversion of Fe3+ to Fe2+ in anaerobic respiration?

Reductive

What kind of process is the conversion of sulfate to hydrogen sulfide?

Reductive

mycobiont

The fungal component of a lichen

Most useful distinction between cooperation and mutualism is

The observation that cooperating organisms can grow independently, although they may not function as well.

The carbon cycle

The organic circulation of carbon from the atmosphere into organisms and back again

symbiont

The smaller participant in a symbiotic relationship, living in or on the host.

Commensal

describes an organism that lives symbiotically with a host; this host neither benefits nor suffers from the association

Microbial Interactions

more than one kind of organism interacting with each other

Lichens

represent symbiotic relationships between a fungus and a photosynthetic partner

Ruminant stomach

rumen, reticulum, omasum, abomasum

Syntrophy

some bacteria live together and supply each other with essential nutrients

Bacteriocytes

specialized aphid cells

phycobiont

the algae component of a lichen

assimilatory sulfate reduction

the reduction of sulfate for use in amino acid and protein biosynthesis

Competition

the struggle between organisms to survive in a habitat with limited resources