Microbiology - Chapter 7 Microbial Nutrition, Ecology, And Growth (For Test 2)

Front 1

Essential nutrient

Back 1

any substances that must be provided to an organism

Front 2

Macronutrients

Back 2

Macronutrients: Required in relatively large quantities, play principal roles in cell structure and metabolism (ex. C, H, O)

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micronutrients

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Micronutrients: aka trace elements, present in smaller amounts and involved in enzyme function and maintenance of protein structure (ex. Mn, Zn, Ni)

Front 4

How are nutrients categorized according to Carbon content?

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Inorganic nutrients: A combination of atoms other than C and H
Organic nutrients: Contain C and H, usually the products of living things

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define heterotroph

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Heterotroph: Must obtain C in organic form (nutritionally dependent on other living things)

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define autotroph

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Autotroph: Uses inorganic CO2 as its carbon source (not nutritionally dependent on other living things)

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what is the main source of atmospheric nitrogen (N2)?

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The air we breathe

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in order for N2 to be used, it must be:

Back 8

converted to NH3 (ammonia) (the only form that can be directly combined with C to synthesize amino acids and other compounds)

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O2 is a major component of ______ ______ and makes up ______% of the atmosphere.

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organic compounds
20%
(also a common component of inorganic salts)

Front 10

H is a major element in ____ organic and ______ inorganic compounds

Back 10

all
several

Front 11

what are three things H does in the biochemistry of cells

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Maintaining pH
Forming hydrogen bonds between molecules
Serving as the source of free energy in oxidation-reduction reactions of respiration

Front 12

phosphorus in a key component in ___________ ________ and is also found in _____________ and _____________

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nucleic acids
ATP
Phospholipids in cell membranes and coenzymes

Front 13

Describe sulfur sources

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Widely distributed throughout the environment in mineral form
Essential component of some vitamins
Amino acids- methionine and cysteine

Front 14

what role does calcium play in microbial life?

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stabilizer of cell walls and endospores

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potassium is important in

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protein synthesis and membrane function

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what is a growth factor?

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Growth factor: An organic compound such as an amino acid, nitrogenous base, or vitamin that cannot be synthesized by an organism and must be provided as a nutrient
i.e. some amino acids

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what are phototrophs

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Phototrophs- Microbes that photosynthesize

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what are chemotrophs?

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Chemotrophs- Microbes that gain energy from chemical compounds

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describe photoautotrophs

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Photosynthetic
Form the basis for most food webs

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what are the three types of chemoautotrophs

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chemoorganic autotrophs
lithoautotrophs
methanogens

Front 21

what are chemoorganic autotrophs?

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Chemoorganic autotrophs- use organic compounds for energy and inorganic compounds as a carbon source

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what are lithoautotrophs

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Lithoautotrophs- rely totally on inorganic minerals
"rock eaters"

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what are methanogens

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produce methane from hydrogen gas and carbon dioxide
Archae
Some live in extreme habitats

Front 24

Most pathogenic organisms that we see are:

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chemoheterotrophs - they like organic carbon sources
i.e. lipids, carbs

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Is it likely that a phototroph would be a pathogen?

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No

Front 26

what are two examples of chemoheterotrophs?

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saprobes
parasites

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Saprobes are _______ micro-organisms
they feed primarily on _____________

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free-living - like fungi
organic detritus from dead organisms
Decomposers of plant litter, animal matter, and dead microbes

Front 28

how do most saprobes get their nutrition?

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they release enzymes to the extracellular environment and digest food particles into smaller molecules

Front 29

define obligate saprobe

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Obligate saprobes- exist strictly on dead organic matter in soil and water

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define facultative parasite

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Facultative parasite- when a saprobe infects a host, usually when the host is compromised (opportunistic pathogen)

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what are the three types of parasites? Define

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Ectoparasites- live on the body
Endoparasites- live in organs and tissues
Intracellular parasites- live within cells

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what is an obligate parasite?

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Obligate parasites- unable to grow outside of a living host

Front 33

define autotroph

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Autotroph: Uses inorganic CO2 as its carbon source (not nutritionally dependent on other living things)

Front 34

what is the main source of atmospheric nitrogen (N2)?

Back 34

The air we breathe

Front 35

in order for N2 to be used, it must be:

Back 35

converted to NH3 (ammonia) (the only form that can be directly combined with C to synthesize amino acids and other compounds)

Front 36

O2 is a major component of ______ ______ and makes up ______% of the atmosphere.

Back 36

organic compounds
20%
(also a common component of inorganic salts)

Front 37

H is a major element in ____ organic and ______ inorganic compounds

Back 37

all
several

Front 38

what are the three cardinal temperatures of a given microbial species?

Back 38

Minimum temperature: the lowest temperature that permits a microbe’s continued growth and metabolism
Maximum temperature: The highest temperature at which growth and metabolism can proceed
Optimum temperature: A small range, intermediate between the minimum and maximum, which promotes the fast rate of growth and metabolism

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define psychrophile

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A microorganism that has an optimum temperature below 15°C and is capable of growth at 0°C.
True psychrophiles are obligate with respect to cold and cannot grow above 20°C.

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describe psychrotrophs or facultative psychrophiles

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grow slowly in cold but have an optimum temperature above 20°C.

Front 41

describe mesophile

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An organism that grows at intermediate temperatures
Optimum growth temperature of most: 20°C to 40°C
Temperate, subtropical, and tropical regions

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most human pathogens are:

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mesophiles
with optimum temperature between 30°C and 40°C

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describe thermophile

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A microbe that grows optimally at temperatures greater than 45°C
Vary in heat requirements
General range of growth of 45°C to 80°C
Hyperthermophiles- grow between 80°C and 120°C

Front 44

what are the two atmospheric gases that most influence microbial growth? Which one has the greatest impact of the two?

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O2 and CO2

O2 has greatest impact

Front 45

Define aerobe

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Aerobe: can use gaseous oxygen in its metabolism and possesses the enzymes needed to process toxic oxygen products

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define obligate aerobe

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Obligate aerobe: cannot grow without oxygen

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define facultative anaerobe

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Facultative anaerobe: an aerobe that does not require oxygen for its metabolism and is capable of growth in the absence of it

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define microaerophile

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Microaerophile: does not grow at normal atmospheric concentrations of oxygen but requires a small amount of it in metabolism

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define anaerobe

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Anaerobe: lacks the metabolic enzyme systems for using oxygen in respiration

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define strict, or obligate anaerobe

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Strict, or obligate, anaerobes: also lack the enzymes for processing toxic oxygen and cannot tolerate any free oxygen in the immediate environment and will die if exposed to it.

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define aerotolerant anaerobes

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Aerotolerant anaerobes: do not utilize oxygen but can survive and grow to a limited extent in its presence

Front 52

what type of O2 descriptor applies to us?

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obligate aerobe

Front 53

what type of O2 descriptor applies to orgs that die in the presence of any O2?

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strict or obligate anaerobe

Front 54

what type of O2 descriptor applies to orgs that like a lower concentration of O2?

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microaerophile

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what type of O2 descriptor applies to orgs that uses O2 in it metabolism but doesn't require it and can grow without it?

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facultative anaerobe

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what type of O2 descriptor applies to orgs that have the fastest growth rate?

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aerobes

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what are capnophiles?

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organisms that grow best at a higher CO2 tension than is normally present in the atmosphere

Front 58

Majority of organisms live or grow in habitats between pH ___ and ___

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6 and 8

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define halophiles

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Halophiles- prefer high concentrations of salt

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define osmophiles

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Osmophiles- live in habitats with a high solute concentration

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describe barophiles

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deep-sea microbes that exist under hydrostatic pressures ranging from a few times to over 1,000 times the pressure of the atmosphere

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All cells require ___________

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water
(only dormant, dehydrated cell stages tolerate extreme drying)

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Most microbes live in _____ ____
They often involve _____ _____

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shared habitats

nutritional interactions

Front 64

define symbiosis
symbionts

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A general term used to denote a situation in which two organisms live together in a close partnership
Members are termed symbionts

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what are the three main types of symbionts?

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mutualism
commensalism
parasitism

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define mutualism

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Mutualism: when organisms live in an obligatory but mutually beneficial relationship

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define commensalism

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the member called the commensal receives benefits, while its coinhabitant is neither harmed nor benefited

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define parasitism

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Parasitism: a relationship in which the host organism provides the parasitic microbe with nutrients and a habitat

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what is satellitism?

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at type of commensalism when one member provides nutritional or protective factors needed by the other

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define nonsymbiotic

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Organisms are free-living and relationships are not required for survival

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what are the two types of nonsymbiotic relationships?

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synergism
antagonism

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define synergism

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Synergism: an interrelationship between two or more free-living organisms that benefits them but is not necessary for their survival

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define antagonism

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an association between free-living species that arises when members of a community compete

Front 74

Interrelationships Between microbes and Humans can be what type of relationship (s)

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commensal, parasitic, and synergistic relationships

Front 75

describe the two levels of mircrobial growth

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Cell synthesizes new cell components and increases in size
The numer of cells in the population increases

Front 76

what is the basis of microbial population growth?

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binary fission (basically mitosis)

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define generation or doubling time

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The time required for a complete fission cycle

Front 78

Each new fission cycle or generation increases the population by a factor of ____
As long as the environment is favorable, the doubling effect continues at a ____ _____

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2

constant rate

Front 79

what can be a limiting factor in the growth rate of microbes?

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nutrients and waste products