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microbial physiology

the study of vital life processes representative of all organisms


chemical substances used in metabolism and growth


required in large amounts and is important in cell structure and metabolism

macronutrient examples

proteins, lipids, carbohydrates (basic cell structure)


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


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


decompose dead organisms


utilize tissues and fluids of a living host and cause harm


component of all biological cells

carbon functions

energy sources/ structural components (cell building)


organisms that must obtain carbon in an organic form- they feed on other organisms or the products of other organisms metabolism


organisms that use CO2 , an inorganic gas, as it carbon source


all organisms require this to drive cellular processes


extraction of energy from organic nutrients is a major role of this


categorized by their source of carbon and source of energy


CO2 / sunlight/ Inorganic


CO2/ simple inorganic chemical/ Inorganic


Organic/ sunlight


Organic/ organic compounds


=get food from carbon


vital to cell structure and function


movement of a substance across the plasma membrane

passive transport

does not require energy, follows concentration gradient


O2 and CO2 are transported freely


passive transport of water


net zero


fresh water, very low solute


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


flucuations in metabolism, morphology, transport, protein configuration

3 cardinal temperature

minimum, maximum, optimum


lowest temp. that permits a microbes growth and metabolism


highest temp. that permits a microbes growth and metabolism


best temp promotes fastest rate of growth and metabolism


optimum temp below 15C - like the cold enviroment


otimum temps 20C to 40C - most human pathogens


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


occurs when enzymes detoxify and nuetralize the oxidizing agent

adaption examples

catalase and superoxide dismutase


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


lacks the metabolizing enzyme system for using gas in respiration----growth only in bottom of tube


do not utilize oxygen gas but can grow in its presence--some growth in tube


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


more tolerant of lower ph


more tolerant of higher ph


like more acidic enviroment 0-2


like more basic enviroment up to 10 ph

osmotic pressure

determines the tonicity


are adapted to high level of salt- Archeans, prokaryotes


adapted to high barometric pressure


close nutritional relationships between organisms-essential and beneficial to at least one member


both members must benefit

mutualism examples

protozoa digests,cellulose for termites, bacteria breakdown cellulose for ruminates, E.coli produces vit k in large intestine


commensal benefits, they can co-exist, other member unharmed

commensalism examples

feed on dead cells, residual food in mouth


a dependant form of commensalism.

satellitism examples

one provides growth factors for other, or break down toxins


parasite benefits; host is harmed

non symbiotic

organisms are free-living; relationships not required for survival


members cooperate and share nutrients, non essential

synergism examples

biofilms -cooperatives of many different organisms


one member is inhibited or destroyed by another, competition for resources


production of inhibitory chemicals

binary fission

one cell splits into 2


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


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

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