Exam 3 Flashcards by Karisa Martinez

What are ubiquitous microbes?

microbes that colonize all habitats; they are everywhere and can be a variety of species

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What are resilient microorganisms?

microorganisms that grow under different physical conditions

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What are some factors that affect microbial growth

oxygen, light, temperature, pH, osmotic pressure

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Where can microorganisms be found?

everywhere

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What are ecosystems?

combination of biotic and abiotic factors that all interact as a functional unit

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What are habitats?

the physical part of an ecosystem best suited for a population

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What is a population?

multiple individuals of same species that live and thrive in the same habitat

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What is a community?

one or multiple populations of the same or different species

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What is species richness?

absolute number of species present

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What is species abundance?

the relative abundance of each species in that community; aka, number of individuals per species

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What is a microenvironment?

surrounding, small scale, environment of a microorganism

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What is a niche?

range of resources and conditions allowing the species to maintain a viable population

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What is a fundamental niche?

all possible situations where an organism can thrive with a stable population

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What is a realized niche?

the most successful niche

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What determines the growth rate of microorganisms?

nutrient availability and how efficiently they can break down nutrients

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In nature, are exponential growth rates common or rare?

rare, bc
1. resources & growth rates are rare
2. distribution of nutrients in microenvironment are not uniform
3. mixed populations

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What are biofilms?

large masses of bacteria, highly organized

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Define symbiosis?

stable associations between microbial populations and their microenvironment

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Define microbial ecology

the study of symbiotic associations between microbial populations and their microenvironment

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Cooperative relationships

benefit populations

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Competitive relationships

occur when populations compete for resources

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Define mutualism

both species benefit from and need each other; meaning they co-evolved

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Define cooperation

both species benefit from each other, but they do not need each other(obligatory)

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Define commensalism

one organism benefits, while the other is unaffected

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Define syntrophy

cross feeding

Define amensalism

one organism harmed, while the other is unaffected

Define predation

one species kills the other; not obligatory

Define parasitism

one microorganism benefits, the other is harmed

Define competition

two different species competing for the same nutrient

What are the antagonistic relationships?

predatin, parasitism, and competition

Produces are

autotrophs; have unlimited energy

Where do consumers derive their nutrients from?

derive nutrients from producers

Where do decomposers derive their nutrients from?

derive nutrients from consumers

Why does energy decrease as it goes up the food chain?

energy decreases as it goes up the food chain because of entropy and the law of thermodynamics(II)

What is mineralization?

recycling of material to be used by primary consumers

The cooler the water, the _______ the oxygen concentration.

higher

What are some examples of gradients?

sunlight, nutrient availability, aeration, temperature

What is the microbial loop?

a close community of microbes that maintain nutrient flow and cycling

Define oligotrophic

nutrient deficient; thrive in dilute environments; ie: dilute environments

What is eutrophic

nutrient rich

Define Eutrophication

oligotrophic environment made eutrophic; ie: sewage, agriculture

What is potable water?

water safe to drink; still has microorganisms, but nonpathogenic

How is water monitored?

using indicator bacteria

What are indicator bacteria?

coliforms and enterococci

What are assays?

standard plate count and membrane filter tests

Who started the process of pasteurization?

Louis Pasteur, using milk

Who began the development of canning?

the French military

What are the beneficial effects of microorganisms?

fermentation; good microorganisms(ie: spirulina)

What the detrimental effects of microorganisms?

food spoilage and food poisoning

Define food spoilage

a change in appearance, smell, or taste, making it undesirable

What are intrinsic factors?

parameters of plant/animal tissues that are an inherit part of tissues

What are some examples of intrinsic factors?

pH, physical structure, proteins

What are extrinsic factors?

factors that influence from the outside

What are some examples of extrinsic factors?

temperature, humidity, and the atmosphere food is stored in

How can we reduce microbes?

filtration, canning, pasteurization, radiation

How can we prevent growth?

-maintenance of temperature -preservatives/additives

Define pasteurization

controlled heat to reduce the microbial load, including pathogens and spoilage organisms

What are the different types of pasteurization?

-low temp. holding -high temp. holding -ultra high temp.

Define canning

canned goods undergo commercial sterilization via steam under pressure; intended to destroy Clostridium botulinum

Define radiation

short wavelength light kills microorganisms

Define non-ionizing radiation

good for surfaces of food and utensils; UV light

Ionizing radiation

very effective and safe; -x rays -electron beams -gamma radiation

What temperature slows down microbial growth?

5 C

Why is food stored in freezer temperatures?

long term storage

What temperature is used to reduce microbial growth?

60C

What is nitrite?

a preservative that inhibits Clostridium botulinum endospore germination

What two ways of reducing water prevents growth?

-desiccation -high osmolarity(high sugar/salt concentration)

How does osmolarity work?

water flows out of the microorganisms due to high sugar concentration

Define food poisoning

disease caused by ingested food -poisonous plants/animals -microbial food borne disease

Define food intoxication

bacterial exotoxin is ingested -caused by the toxin, not bacteria

Define food infection

ingested bacteria whose growth in humans causes disease -associated with diarrhea and abdominal distress

What are alfatoxins

-grow and release toxins in moist grains/nuts -carcinogen: DNA intercalating molecule that promotes frameshift mutations -primarily affects the liver

What are fumonisins?

-grow and release toxins in moist corn -carcinogen: esophageal cancer -inhibit ceramide synthase, disrupting the synthesis and metabolism of sphingolipids, which shows altered cellular signaling

What are starter cultures?

added pure or mixed samples of known bacteria, molds, or yeasts

Describe the food production of bread

-baker's yeast -oxigenic conditions