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104 terms

Microbiology Ch7,Ch8,Ch11

Foundations of Microbiology 8th ed
process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities
Essential nutrients
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
2 types of nutrients
1. organic nutrients
2. inorganic nutrients
organic nutrients
C & H atoms-usually products of living things.(methane, carbohydrates, lipids, proteins, nucleic acids)
inorganic nutrients
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
70% water
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
Growth factors
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)
nutritional types
Carbon source-heterotroph,autotroph
Energy source-chemotroph,phototroph
source of essential nutrient-energy source
1.Chemotroph-gain energy from chemical compounds(humans)
2.Phototrophs-gain energy through photosynthesis
gain energy from chemical compounds(humans)
gain energy through photosynthesis
autotrophs and their energy source
1.oxygenic photosynthesis-algae,plants
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
-aerobic respiration
1. saprobes-free living microorganisms that feed on
organic detritus from dead organisms(decomposers)
-opportunistic pathogen
-facultative parasite/not obligate
2.parasites-derive nutrients from host(living host)
-some are obligate parasites
sunlight or organic matter (purple and green sulfur photosynthetic bacteria)
sunlight-photosynthetic organisms, such as algae, plants, cyanobacteria
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) 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)
2.pinocytosis-ingests liquids
totality of adaptions organisms make to their habitat
Environmental factors affect the function of
metabolic enzymes (proteins)
Factors that influence microbes
2.oxygen requirements
4.Osmotic pressure
5.Barometric pressure
3-cardinal temperatures
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
3-temperature adaption groups
psychrophiles-cold, freezing
mesophiles-most humans
toxic products of oxygen
singlet oxygen,superoxide ion,peroxide, hydroxyl radicals
enzymes that neutralize toxic products of oxygen
superoxide dismutase, catalase
categories of oxygen requirments
Aerobe,obligate aerobe,facultative anaerobe,microaerophilic, anaerobe, obligate anaerobe, aerotolerant anaerobes
utilizes oxygen and can detoxify it
obligate aerobe
cannot grow without oxygen
facultative anaerobe
utilizes oxygen but can also grow in its absence
requires only a small amount of oxygen
does not utilize oxygen
obligate anaerobe
lacks the enzymes to detoxify oxygen os cannot survive in an oxygen environment
aerotolerant anaerobes
do not utilize oxygen but can survive and grow in its presence
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
grow at a pH between 6-8
grow at extreme acid pH
grow at extreme alkaline pH
require a high concentration of salt
do not require high concentration of solute but can tolerate it when it occurs
can survive under extreme pressure and will rupture if exposed to normal atmospheric pressure
microbial asssociations
symbiotic-organisms live in close nutritional relationships;required by one or both members
nonsymbiotic-organisms are free-living;relationships not required for survival
organisms live in close nutritional relationships;required by one or both members
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
-commensal, parasitic,synergistic
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
quorum sensing
communicate and cooperate in the formation and function of biofilms(use chemical signals) cooperate to produce enzymes
inducer molecule
in quorum sensing-stimulates expression of a particular gene and synthesis of a protein product, such as an enzyme
2 levels of microbial growth
cellular level-increase in size
division of bacterial cells occurs mainly through
binary fission(transverse)
binary fission
(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)
exponential generation time
the doubling of cells each time in binary fission
generation or doubling time
time required for a complete fission cycle
minutes or days
exponential growth
each new fission cycle increases the population by a factor of 2
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
3.stationary phase
4.death phase
methods of analyzing population growth
1.viable plate count
3.enumeration of bacteria-viable colony count,direct cell count
growth curve
in laboratory studies, populations typically display a predictable pattern over time
all chemical and physical workings of a cell
2 types of chemical reactions
1.catabolism-release energy,degredation
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 ___________.
simple enzyme
consist of protein ALONE
conjugated enzyme
holoenzyme-contain protein and nonprotein molecules
protein portion of enzyme
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)
coenzyme cofactors
ORGANIC MOLECULES;vitamins (growth factors)
metallic cofactors
INORGANIC ION; iron,copper, magnesium(trace elements)
catalase enzyme
breaks down hydrogen peroxide
metallic cofactor required-iron
oxidase enzyme
adds electrons to oxygen
metallic cofactor required-iron,copper
hexokinase enzyme
transfers phosphate to glucose
metallic cofactor required-magnesium
urease enzyme
splits urea into an ammonium ion
metallic cofactor required-nickel
nitrate reductase enzyme
reduces nitrate to nitrite
metallic cofactor required-molybdenum
DNA poymerase complex
synthesis of DNA
metallic cofactor required-zinc and magnesium
active site
catalytic site-site for substrate binding
induced fit
a temporary enzyme-substrate union occurs when substrate moves into active site
-appropriate reaction occurs;product is formed and released
location of enzyme action
transported extracellularly, where they break down large food molecules or harmful chemicals
retained intracellularly and function there (majority)
regularity of enzyme action
1.constitutive enzymes
2.regulated enzymes
constitutive enzymes
always present, always produced in equal amounts or at equal rates, regardless of the amount of substrate
regulated enzymes
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
hydrolysis reactions
need water, catabolic reactions that break down substrates into small molecules;requires the input of water to break bonds
chemically UNstable enzymes
caused by;
changes to temperature, pH, osmotic pressure of organisms habitat
Ex. denaturation-weak bonds that maintain the shape of the apoenzyme are broken
weak bonds that maintain the shape of the apoenzyme are broken
multienzyme systems
metabolic pathways
product of substrate input=substrate for next enzyme
competitive inhibition`
substance that resembles the normal substrate competes with the substrate for the active site
noncompetitive inhibition
(allosteric inhibition)
enzymes are regulated by the binding of molecules other than the substrate away from the active site
enzyme repression
inhibits at the genetic level by controlling synthesis of the enzymes
enzyme induction
enzymes are made only when suitable substrates are present
the capacity to do work or to cause change
endergonic reactions
(anabolic)-consume energy
energy + A + B--enzyme--C
exergonic reactions
(catabolic)-release energy
X + Y--enzyme--Z + energy
energy released in temporarily stored in high energy ______molecules.
the energy of these molecules is used in endergonic cell reactions.
redox reactions
-always occurs in pairs
-electron acceptor and electron donor
-process salvages electrons & their energy
-released energy can be captured to phosphorylate ADP or another compound