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92 terms

Chapter 7 Microbial Nutrition

STUDY
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microbial physiology
the study of vital life processes representative of all organisms
nutrients
chemical substances used in metabolism and growth
macronutrients
required in large amounts and is important in cell structure and metabolism
macronutrient examples
proteins, lipids, carbohydrates (basic cell structure)
micronutrients
needed in small amounts and is involved in the enzyme function and maintenance of protein structure
micronutrients examples
magnesium, zinc, nickel
essential nutrients
materials that cannot be made by an organism but necessary to sustain life and must be supplied by the diet.
essential nutrient examples
amino acids, fatty accids, vitamins
70% water
cytoplasm
96% 6 elements
CNSHOP-carbon, nitrogen, sulfur, oxygen, hydrogen, phosphorus
organic nutrients
contain carbon and hydrogen atoms and are the products of living things
organic examples
hydrocarbons- methane ; macromolecules-carbohydrates, lipids, proteins, and nucleic acid
inorganic nutrients
trace elements
inorganic examples
metals and their salts (potassium, calcium, sodium, magnesium, iron); gases (oxygen, carbon dixiode); water
enviromental sources of nutrients
Air 79% nitrogen 20% oxygen / Water- essential to metabolic processes/ Soil - minerals
saprobes
decompose dead organisms
parasites
utilize tissues and fluids of a living host and cause harm
carbon
component of all biological cells
carbon functions
energy sources/ structural components (cell building)
heterotrophs
organisms that must obtain carbon in an organic form- they feed on other organisms or the products of other organisms metabolism
autotrophs
organisms that use CO2 , an inorganic gas, as it carbon source
energy
all organisms require this to drive cellular processes
metabolism
extraction of energy from organic nutrients is a major role of this
prokaryotes
categorized by their source of carbon and source of energy
photoautotrophs
CO2 / sunlight/ Inorganic
chemoautotrophs
CO2/ simple inorganic chemical/ Inorganic
Photoheterotrophs
Organic/ sunlight
Chemoheterotrophs
Organic/ organic compounds
auto
=get food from carbon
Carbon
vital to cell structure and function
transport
movement of a substance across the plasma membrane
passive transport
does not require energy, follows concentration gradient
diffusion
O2 and CO2 are transported freely
osmosis
passive transport of water
isotonic
net zero
hypotonic
fresh water, very low solute
hypertonic
saltier water, high solute
facilitated diffusion
passive, but requires a membrane protein--protein allows channel to allow passage--polar molecules like H2O & glucose
active transport
carrier mediated active transport requires energy and membrane proteins- faster transport rates- has pump to cross conc. gradient
enviromental factors
affect the rate and amount of growth, survival depends on adaptions to changing envrioments
enviromental factors examples
temperature, oxygen, ph, electromagnetic radiation, barometric and osmotic pressures
temperature
flucuations in metabolism, morphology, transport, protein configuration
3 cardinal temperature
minimum, maximum, optimum
minimum
lowest temp. that permits a microbes growth and metabolism
maximum
highest temp. that permits a microbes growth and metabolism
optimum
best temp promotes fastest rate of growth and metabolism
phychophiles
optimum temp below 15C - like the cold enviroment
mesophiles
otimum temps 20C to 40C - most human pathogens
thermophiles
optimum tem above 45C- archeans- above boiling
oxidizing agent
some organisms can be poisoned by oxygen--cellular damage can occur
oxidizning agent examples
singlet oxygen, superoxide ion, peroxide, and hydroxide radicals are toxic
adaptions
occurs when enzymes detoxify and nuetralize the oxidizing agent
adaption examples
catalase and superoxide dismutase
aerobe
can use gaseous oxygen in its metabolism and posseses the enzymes needed to process toxic oxygen products.
obligate aerobe
cannot grow without oxygen, needs oxygen for growth
facultative anaerobe
does not require oxygen for its metabolism and is capable of growing in the absence of it. ----has growth throughout the tube
obligate anaerobe
lacks the enzymes necessary for processing oxygen; will die if exposed to oxygen
anaerobic
lacks the metabolizing enzyme system for using gas in respiration----growth only in bottom of tube
aerotolerant
do not utilize oxygen gas but can grow in its presence--some growth in tube
microaerophile
does not grow in normal atmospheric oxygen but does need a little oxygen for metabolism---these organisms live in the soil, human body, and water,,,not directly exposed to oxygen---growth in tube just below the surface.
neutral ph range
6-8 6 is more acidic, 8 is more basic
fungi
more tolerant of lower ph
bacteria
more tolerant of higher ph
acidophiles
like more acidic enviroment 0-2
alkalinphiles
like more basic enviroment up to 10 ph
osmotic pressure
determines the tonicity
halophiles
are adapted to high level of salt- Archeans, prokaryotes
baromophiles
adapted to high barometric pressure
symbiosis
close nutritional relationships between organisms-essential and beneficial to at least one member
mutualism
both members must benefit
mutualism examples
protozoa digests,cellulose for termites, bacteria breakdown cellulose for ruminates, E.coli produces vit k in large intestine
commensalism
commensal benefits, they can co-exist, other member unharmed
commensalism examples
feed on dead cells, residual food in mouth
satellitism
a dependant form of commensalism.
satellitism examples
one provides growth factors for other, or break down toxins
parastism
parasite benefits; host is harmed
non symbiotic
organisms are free-living; relationships not required for survival
synergism
members cooperate and share nutrients, non essential
synergism examples
biofilms -cooperatives of many different organisms
antagonism
one member is inhibited or destroyed by another, competition for resources
antibiosis
production of inhibitory chemicals
binary fission
one cell splits into 2
asexual
microbial growh reproduction
generation time
the time elapsed between formation of a new daughter cell and the time when it divides to form 2 new cells
double
population with each generation
normal growth curve
a graphical representation of changes in population size over time
four stages normal growth curve
lag phase, log or exponential phase, stationary phase, and death phase
lag phase
little growth-flat period of adjustment
exponential growth phase
period of maximum growth will continue to grow as long as cells have adequate nutrients and a favorable enviroment
stationary phase
rate of cell growth equals rate of cell death, caused by a depleted amount of nutrients and oxygen excretion of organic acids and pollutants
death phase
as limiting factors intensify cells die exponentially in their own wastes ...these cells are not supported by their enviroment
measurement of bacterial growth
direct total counts by counting dead cells along w/ viable cells, flow cytometer- automated, turbity