Chapter 7 Microbial Nutrition

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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

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