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process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities
must be provided to an organism.
2.micronutrients or trace elements
required in large quantities;play principal roles in cell structure and metabolism(proteins, carbohydrates, nucleic acid)
(trace elements)-required in small amts; involved in enzyme function and maintenance of protein structure(manganese, zinc, nickel)metals
C & H atoms-usually products of living things.(methane, carbohydrates, lipids, proteins, nucleic acids)
NO C & H - atom or molecule that contains a combination of atoms other than carbon and hydrogen(metals,and their salts-magnesium sulfate, ferric nitrate, sodium phosphate), gases (oxygen, carbon dioxide) and water.
chemical analysis of cell contents
proteins-main macromolecule/most abund. in cell
96% other elements
source of essential nutrient-carbon source
1.Heterotroph-obtain by an organic form made by other living organism(proteins, carbohydrates, lipids, and nucleic acids.
2. Autotroph- photosynthesis,uses CO2(from atmoshpere), an inorganic gas as carbon source
ex. archaea- use inorganic chemicals coming out of vents
obtain CARBON SOURCE by an organic form made by other living organism(proteins, carbohydrates, lipids, and nucleic acids.
obtain CARBON SOURCE by;photosynthesis,uses CO2(from atmoshpere), an inorganic gas as carbon source
ex. archaea- use inorganic chemicals coming out of vents
Essential organic nutrients:
organic compounds that cannot be synthesized by an organism because they lack the genetic and metabolic metabolic mechanisms to synthesize them.
-must be provided as a nutrient(essential amino acids, vitamins)
source of essential nutrient-energy source
1.Chemotroph-gain energy from chemical compounds(humans)
2.Phototrophs-gain energy through photosynthesis
autotrophs and their energy source
2.anoxygenic photosynthesis-green & purple sulfur
2.chemoautotrophs-(lithoautotrophs) survive totally on inorganic substances(methanogens, a kind of chemoautotroph, produce methane gas under anaerobic conditions.
heterotrophs and their energy source
majority are chemoheterotrophs
1. saprobes-free living microorganisms that feed on
organic detritus from dead organisms(decomposers)
-facultative parasite/not obligate
2.parasites-derive nutrients from host(living host)
-some are obligate parasites
simple inorganic chemicals, only certain bacteria, such as methanogens, deep-see vent bacteria
metabolic conversion of the nutrients from other organisms,protozoa, fungi, many bacteria, animals
1. saprobe-organic matter of dead organisms (decomposers)
2. parasite- tissues fluids of living host(various parasites & pathogens;can be bacteria, fungi,protozoa, animals
2 types of movement of chemicals across the cell membrane
1. passive transport-NO ATP, moves in gradient areas of higher concentration-areas of lower conc.
2. osmosis-diffusion of water
3.facilitated diffusion-requires carrier(protein channel)
2. active transport-ATP and carrier proteins(gradient INDEPENDENT)
1.group translocation-transported molecule chemically altered as enter cell.
2.bulk transport-endocytosis,exocytosis,pinocytosis, bring in a lot of substance at one time
3.carrier mediated active transport-membrane proteins (permeases) have attachment sites for essential nutrient molecules. (ex.ATP or PROTON MOTIVE FORCE)
bringing substances into the cell through a vesicle or phagosome
1.phagocytosis-ingests substances or cells(when vacuole fuses w/ lysosome)
Factors that influence microbes
1.minimum temperature-lowest temp that permits a microbe's growth and metabalism
2.maximum temperature-highest temp that permits a microbe's growth and metabalism
3.optimum temperature-promotes the fastest rate of growth and metabolism
categories of oxygen requirments
Aerobe,obligate aerobe,facultative anaerobe,microaerophilic, anaerobe, obligate anaerobe, aerotolerant anaerobes
grows best at higher CO2 tensions than normally present in the atmosphere(less oxygen more CO2)
effects of Ph
acidophiles-grow in extreme acid pH
alkalinophiles-grow in extreme alkaline pH
can survive under extreme pressure and will rupture if exposed to normal atmospheric pressure
symbiotic-organisms live in close nutritional relationships;required by one or both members
nonsymbiotic-organisms are free-living;relationships not required for survival
3 types of symbiotic associations
1.mutualism-obligatory, dependent;both members benefit (both benefit)
2.commensalism-commensal benefits;other member not harmed (1 gains/other not harmed)
3.parasitism-obligate,parasite is dependent and benefits;host harmed (1 gains/other harmed)
2 types of nonsymbiotic associations
1.synergism-members cooperate and share nutrients,produce result that none of them could do alone.
2.antagonism-some members are inhibited or destroyed by others(competition) antibiosis
interrelationship between microbes and humans
human body is a rich habitat for symbiotic bacteria, fungi, and a few protozoa-NORMAL MICROBIAL FLORA
NORMAL MICROBIAL FLORA
human body is a rich habitat for symbiotic bacteria, fungi, and a few protozoa
result when organisms attach to a substrate by some form of extracellular matrix that binds them together in complex organized layers
communicate and cooperate in the formation and function of biofilms(use chemical signals) cooperate to produce enzymes
in quorum sensing-stimulates expression of a particular gene and synthesis of a protein product, such as an enzyme
(transverse)-parent cell enlarges, duplicates its chromosome, and forms a central transverse septum dividing the cell into 2 daughter cells
-doubles each time(exponential generation time)
Nf=total # cells in population
ni=starting # cells
n=denotes generation time(specific for organism)
2n=number of cells in that generation
population growth curve
1.lag phase-flat,period of adjustment,enlargement, little growth
2.exponential growth phase
methods of analyzing population growth
1.viable plate count
3.enumeration of bacteria-viable colony count,direct cell count
2 types of chemical reactions
2.anabolism-needs energy,biosynthesis(making building)
energy of activation
enzymes are biological catalyst that increase the rate of a chemical reaction by lowering the ___________.
nonprotein portion of enzyme (INORGANIC ION)
act as carriers to assist the enzyme in its activity.
1.metallic cofactors-INORGANIC ION; iron,copper, magnesium(trace elements)
2.coenzymes-ORGANIC MOLECULES;vitamins(growth factors)
a temporary enzyme-substrate union occurs when substrate moves into active site
-appropriate reaction occurs;product is formed and released
transported extracellularly, where they break down large food molecules or harmful chemicals
always present, always produced in equal amounts or at equal rates, regardless of the amount of substrate
not constantly present;production is turned on (induced)or turned off(repressed)in response to changes in the substrate concentration
synthesis or condensation reactions
release water,anabolic reactions to form covalent bonds between smaller substrate molecules, require ATP, release 1 molecule of water for each bond formed
need water, catabolic reactions that break down substrates into small molecules;requires the input of water to break bonds
chemically UNstable enzymes
changes to temperature, pH, osmotic pressure of organisms habitat
Ex. denaturation-weak bonds that maintain the shape of the apoenzyme are broken
product of substrate input=substrate for next enzyme
substance that resembles the normal substrate competes with the substrate for the active site
enzymes are regulated by the binding of molecules other than the substrate away from the active site
energy released in temporarily stored in high energy ______molecules.
the energy of these molecules is used in endergonic cell reactions.
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