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457 Cards in this Set

  • Front
  • Back
What is a microbe?
-microscopic life-forms
-Can only be seen through a microscope
How many bacteria can fit on the head of a pin?
Approx. 1 million
Why is knowledge of microbes important?
-Food safety
-Combat disease
-Biotechnology
What didn't we know prior to the knowledge of microbes?
-Why food spoils
-Causes of infectious disease
-True cause of fermentation
-Global geochemical cycles
What features should look for when searching for life on mars?
-organization
-Reproduction
-Metabolism
-Motion
what are lithotrophs?
chemlithotrphs are bacteria that consume minerals
-cause microbial corrosion
What is the common name for Yersinia Pestis?
Bubonic Plague
The first person to observe distinct units of living material; he called them "cells"
Robert Hooke
Published Micrographia; the first publication concerning the microscopic world
Robert Hooke
Antoni van Leeuwenhoek
Cloth Merchant
--initially developed lenses for use in determining quality of fabrics

Observed bacteria with a single lens

first person to observe single celled organisms

his single lenses were stronger than Hooke's micrscope
Observed that very small animals lived between his teeth; he hypothesized that they were alive
Antoni van Leeuwenhoek
This man proved that spontaneous generation was not the cause of maggots;
Francesco Redi

-Sealed meat in a container... never developed maggots

-Meat open to air... developed maggots

-sealed meat still rotted though... unintensionally left room for the spontaneous generation of microbes; proved wrong by Spallanzani

-Life comes from life; Aristotle is wrong
Lazzaro Spallanzani
Sterilization of meat via boiling prevents meat from rotting in sealed container; microbes didn't form.

intended to show that spont gen is false... opposition said life force could not get in to the sealed container.
Florence Nightingale (1820-1910)
-First recognized the sig of disease in warfare

-Founder of professional nursing

-Founder of medical statistics
Founder of medical statistics:
Florence Nightingale
Discovered the fundamental chemical property of chirality (mirror symmetry)
Louis Pasteur
Discovered that fermentation is caused by living yeast, a single-celled fungus:
Louis Pasteur
List Louis Pasteur's scientific contributions:
- Chirality

- Fermentation (life w/o oxygen)

- Disproved spontaneous generation

- Pasteurization

- Pasteur Institute

- Transmission of Germs is the cause of many diseases

- First to recognize the significants of attenuation (weekened pathogens)
This person FULLY disproved spontaneous generation using a swan-necked flask:
Louis Pasteur
The theory that many diseases are caused by microbes:
The Germ Theory of Disease
The first person to establish a scientific basis for determining that a specific microbe causes a specific disease:
Robert Koch (german physician)
Koch's 4 Postulates:
1. The microbe is found in all cases of the disease, but is absent from healthy individuals

2. The microbe is isolated from the diseased host and grown in pure culture

3. When the microbe is introduced into a healthy susceptible host (or animal model), the same disease occurs.

4. The same strain of microbe is obtained from the newly diseased host. When cultured the strain shows the same characteristics as before.
Why did Koch benefit greatly from the development/ use of agar as a growth media?
Koch needed a pure, nutrient media to grow a pure culture.

-was the first effective medium for growth of tuberculosis bacteria
Suggested the use of agar as a pure media:
Angelina Hesse
______ showed a chain of infection via anthrax infected rodents.
Koch
________ discovered that it was possible to innoculate persons from smallpox using an attenuating form of the virus.
Lady Montagu

-observed women in Turkey
Edward Jenner is important why?
confirmed that exposure to cowpox, a mild virus, produced the same effect as exposure to the attenuated smallpox virus.
--safer form of innoculation
--developed the practice of vaccination (vacca = cow)
Developed the practice of aseptic techniques during surgery and imployed the use of antiseptics in the operatory:
Joseph Lister (1865)
Discovered Penicillin:
Alexander Flemming (1929-1941)
Define: Antibiotic
Agent that kills microbes alone leaving host unharmed
Define: Antiseptic
Agent that kills microbes (includes host)
This person used 2D gel electrophoresis to create the first protein catalog of E. Coli
Fred Neidhardt
The bacterial cell wall consists of __________, an organic polymer that constitutes nearly 1% of the cell mass.
peptidoglycan
List 3 techniques commonly used to lyse cells.
- Mild Detergent Lysis

- Freezing and Thawing

- Sonication
What is the equation used to determine the Svedberg Coefficient?
S = v/w^2r

v= rate of sedimentation
w= rotational velocity
r= radius at which the tube rotates
The major phospholipid of E. Coli.
phosphotidylethanolamine
A polymer of galactose that is used as a gelling agent
Agar
A molecule that can kill or inhibit the growth of selected microorganisms.
antibiotic
Winogradsky column
A tube containing a stratified environment that causes specific microbes to grow at particular levels; a type of enrichment culture for the growth of microbes from wetland environments.
An acellular particle containing a genome that can replicate only inside a cell.
virus
Exposure of an individual to a weakened version of a microbe to provoke immunity and prevent development of disease upon re-exposure.
Vaccination
Ultracentrifuge
A machine that exposes samples to high centrifugal forces and can be used to separate subcellular components.
A bacterial enzyme that cleaves double-stranded DNA within a specific short sequence, usually a palindrome. Often called a restriction enzyme.
Restriction Endonuclease
The Gain of Electrons
Reduction
recombinant DNA
DNA that has been combined with other DNA to create novel DNA sequences.
An organism or group of organisms that have multiple evolutionary origins is
polyphyletic
The metabolic ability to absorb and convert solar energy into chemical energy for biosynthesis; a precise definition includes CO2 fixation.
Photosynthesis
nitrogen fixation
The ability of some prokaryotes to reduce inorganic diatomic nitrogen gas (N2) to two molecules of ammonium ion (2 NH4+).
A group of organisms that includes an ancestral species and all of its descendents.
monophyletic
An autotrophic organism that gains energy by oxidizing inorganic compounds; also chemoautotroph.
lithotrophs
immunization
The stimulation of an immune response by deliberate inoculation with a weakened pathogen, in hopes of providing immunity to disease caused by the pathogen.
The theory that many diseases are caused by microbes
germ theory of disease
The global interconversion of various inorganic and organic forms of elements.
geochemical cycling
genome
The complete genetic content of an organism. The sequence of all the nucleotides in a haploid set of chromosomes.
The production of ATP via substrate level phosphorylation, using organic compounds as both electron donors and electron acceptors.
Fermentation
The use of selective growth media to allow only certain microbes to grow
enrighment culture
electron microscope
A microscope that obtains high resolution and magnification by focusing electron beams on samples using magnetic lenses.
A technique to determine the order of bases in a DNA sample.
DNA sequencing
chain of infection
The serial passage of a pathogenic organism from an infected individual to an uninfected individual, thus transmitting disease.
An appliance that uses pressurized steam to sterilize materials by raising the temperature above the boiling point of water at standard pressure.
Autoclave
An environment that is free of microbes is considered
aseptic
Active Transport
An energy-requiring process that moves molecules across a membrane against their electro-chemical gradien
The ability of an organism to attach to a substrate.
adherence
A protein complex that synthesizes ATP from ADP and inorganic phosphate using energy derived from the transmembrane proton potential. It is located in the prokaryotic cell membrane and in the mitochondrial inner membrane.
ATP synthase
A slippery outer layer composed of polysaccharides that surrounds the cell envelope of some bacteria.
capsule
A protein-bounded compartment containing rubisco to fix CO2.
carboxysome
cardiolipin
A double phospholipid linked by glycerol.
-Diphosphatidylglycerol
-Increases in concentration in bacteria grown to starvation or stationary phase, possibly because its extended structure stabilizes the membrane
The phospholipid bilayer that encloses the cytoplasm.
Cell Membrane
A rigid structure external to the cell membrane. The molecular composition depends on organism; composed of peptidoglycan in bacteria.
cell wall
A protein that helps other proteins fold into their correct tertiary structure.
Chaperone
The ability of organisms to move towards or away from specific chemicals.
Chemotaxis
A sterol lipid found in eukaryotic cell membranes.
Cholesterol
An organelle in eukaryotic microbes that pumps water out of the cell.
Contractile Vacuole
A sugar chain that attaches to the glucosamine of lipopolysaccharides and extends outside the cell.
Core Polysaccharide
An attachment that links parallel molecules such as the peptide link between glycan chains in peptidoglycan.
Cross-bridge
A type of potential energy formed by the combined concentration gradient of a molecule and the electrical potential across a membrane.
electrochemical potential
A technique to separate charged proteins and nucleic acids based on how rapidly they migrate in an electric field through a gel.
electrophoresis
Lipopolysaccharides in the outer membrane of gram negative bacteria that become toxic to the host after the bacterial cell has lysed are considered
endotoxins
Structures external to the cell membrane such as a cell wall or outer membrane.
Envelope
A filamentous structure for motility. In prokaryotes, a helical protein filament attached to a rotary motor; in eukaryotes, an undulating cell membrane-enclosed complex of microtubules and ATP driven motor proteins.
Flagellum (plural, flagella)
An organelle that traps gasses to increase buoyancy of aquatic microbes.
gas vesicle
Determination of the function of cell RNAs and proteins based on the phenotype of cells in which the gene encoding the RNA or protein is mutated.
Genetic Analysis
A glucose modified with an amine group
glucosamine
A protein that unwinds the DNA helix.
helicase
Adhesion factors secreted by the tip of a stalk to firmly attach an organism to a substrate.
holdfast
Five-ringed hydrocarbon lipids found in bacterial cell membranes.
Hopane (Hopanoid)
In gram-negative bacteria, the membrane in contact with the cytoplasm, equivalent to the cell membrane.
Inner Membrane
A technique that separates proteins based on their charge.
Isoelectric Focusing
Structurally unique phospholipids found in the outer leaflet of the outer membrane in gram-negative bacteria. Many are endotoxins.
LPSs
The contents of broken cells; may include virus particles.
Lysate
An organelle containing the mineral magnetite that allows microbes to sense a magnetic field.
Magnetosome
The ability to direct motility along magnetic field lines.
Magnetotaxis
An acid that exists in charged and uncharged forms such as acetic acid. The uncharged form can cross the membrane.
membrane-permeant weak acid
A base that exists in charged and uncharged forms such as methylamine. The uncharged form can dissolve in the membrane.
membrane-permeant weak base
The ability of a microbe to generate self-directed movement.
motility
The major lipoprotein that connects the outer membrane of gram-negative bacteria to the peptidoglycan cell wall.
murein lipoprotein
The looped coils of a bacterial chromosome.
nucleoid
A sugar chain that connects to the core polysaccharide of lipopolysaccharides.
O Polysaccharides
A DNA sequence at which DNA replication initiates. In a bacterial chromosome this site is also attached to the cell envelope.
Origin of Replication (ori)
Exerted by the flow of water through a semipermeable membrane.
Osmotic Pressure
Outer Membrane
A membrane external to the cell wall in gram-negative bacteria.
Net movement of molecules across a membrane without energy expenditure by the cell.
Passive Transport
A thick, flexible cell covering found in protists.
Pellicle
A polymer of peptide-linked chains of amino sugars; a major component of the bacterial cell wall.
peptidoglycan
A temperature at which a temperature sensitive mutation in a gene is masked, permitting growth of the organism.
permissive temperature
A negatively charged phosphate head group of a phospholipid.
phosphatidate
A type of phospholipid with a positively charged ethanolamine attached to the phosphate group
phosphatidylethanolamine
A type of phospholipid with a glycerol attached to the phosphate group.
phosyphatidylglycerol
A protein complex that captures light in photosynthetic bacteria.
phycobilisome
The protein monomer that polymerizes to form a pilus.
pilin
A straight protein filament composed of a tube of protein monomers that extend from the bacterial cell envelope.
Pilus (plural, pili)
A positively charged molecule containing multiple amine groups.
polyamine
A cell structure consisting of multiple ribosomes performing translation on the same mRNA molecule.
polysome
A transmembrane protein complex that allows movement of specific molecules across the cell membrane or the outer membrane.
porin
All the proteins expressed in a cell at a given time. The "complete" includes all the proteins the cell can express under any condition. The "expressed" represents the set of proteins made under a given condition.
proteome
The loss or mutation of DNA encoding unselected traits.
reductive evolution
The single covalent molecule that comprises the bacterial cell wall.
sacculus
The rate at which particles of a given size and shape travel to the bottom of a tube under centrifugal force. The rate depends on the particle's mass and cross-sectional area.
sedimentation rate
The formation of a septum, a new section of cell wall and envelope to separate two prokaryotic daughter cells.
septation
A pilus specialized for DNA transfer between bacteria.
sex pilus
A receptor that recognizes the signal sequence of peptides undergoing translation. The complex attaches to the cell membrane of prokaryotes (or the rough endoplasmic reticulum of eukaryotes), where it docks the protein-ribosome complex to the membrane for protein membrane insertion or secretion.
signal recognition particle (SRP)
A crystalline protein surface layer replacing or external to the cell wall in many species of archaea and bacteria.
S-Layer
An extension of the cytoplasm and envelope that attaches a microbe to a substrate.
Stalk
A hexagonal arrangement of cells formed by septation in random orientations.
staphylococcus
A procedure to separate cell components; often includes ultracentrifugation
subcellular fractionation
An extra twist or turn found in DNA, either positive (increases DNA winding) or negative (decreases DNA winding).
supercoil
A measure of particle size based on the particle's sedimentation rate in a tube subjected to a high g force.
Svedberg coefficient
Chains of phosphodiester-linked glycerol or ribitol that thread through and reinforce the cell wall in gram-positive bacteria.
teichoic acid
A branched lipid derived from isoprene that is found in hydrocarbon chains of archaeal membranes.
Terpenoid
A chlorophyll-containing membrane folded within a phototrophic bacterium or a chloroplast.
Thylakoid
A procedure to separate cell components; often includes ultracentrifugation
subcellular fractionation
A membrane protein that moves specific molecules across a membrane.
Transport Protein (transporter)
An extra twist or turn found in DNA, either positive (increases DNA winding) or negative (decreases DNA winding).
supercoil
A technique to separate proteins based on differences in charge and molecular weight.
two-dimensional polyacrylamide gel electrophoresis
A measure of particle size based on the particle's sedimentation rate in a tube subjected to a high g force.
Svedberg coefficient
Chains of phosphodiester-linked glycerol or ribitol that thread through and reinforce the cell wall in gram-positive bacteria.
teichoic acid
A branched lipid derived from isoprene that is found in hydrocarbon chains of archaeal membranes.
Terpenoid
A chlorophyll-containing membrane folded within a phototrophic bacterium or a chloroplast.
Thylakoid
A membrane protein that moves specific molecules across a membrane.
Transport Protein (transporter)
A technique to separate proteins based on differences in charge and molecular weight.
two-dimensional polyacrylamide gel electrophoresis
An ATP powered transport system that contains an ATP binding cassette
ABC transporter
A transport protein in which the molecules being transported move in opposite directions across the membrane.
antiport
An organism that can reduce carbon dioxide to produce organic carbon for biosynthesis.
autotroph
The ability of an organism to grow in the absence of any other species, as, for example, in a pure culture
axenic growth
The growth of bacteria in a closed system without inputs of nutrients.
Batch Culture
The process of replication in which one cell divides to form two daughter cells of equal size.
Binary Fission
A community of microbes growing on a solid surface.
Biofilm
An organism that oxidizes inorganic compounds to yield energy and reduce carbon dioxide.
chemoautotroph
The oxidation of inorganic compounds to yield energy used to reduce carbon dioxide.
chemoautotrophy
An organism that oxidizes organic compounds to yield energy.
chemoheterotroph
The oxidation of organic compounds to yield energy without the use of light.
chemoheterotrophy
A continuous culture system in which the introduced media contains a limiting nutrient.
chemostat
Metabolism that yields energy from oxidation-reduction reactions without using light energy.
Chemotrophy
A metallic ion or a coenzyme required by an enzyme to perform normal catalysis.
cofactor
A nutrient-rich growth solution including undefined chemical components such as beef broth.
complex medium
A lawn of organisms that have completely covered a surface.
confluent
A culture system in which new medium is continually added to replace old medium.
Continuous Culture
A device to count cells based on increasing electrical resistance as cells pass through a small hole
Coulter counter
The movement of a substance against its electrochemical gradient (from lower to higher concentration, or from opposite charge to like charge) using the energy provided by the simultaneous movement of a different chemical down its electrochemical gradient.
coupled transport
The period of cell culture following stationary phase, in which cells die faster than they replicate.
death phase
The rate at which cells die; exponential during the death phase
death rate
A solution of known compounds for organismal growth that contains only the minimal components required for growth
defined minimal medium
Energy-yielding metabolism that involves the reduction of nitrate (NO3 -) to nitrite (NO2 -), diatomic nitrogen, N2, and in some cases ammonia (NH3).
denitrification
A growth medium that can distinguish between various bacteria based on metabolic differences.
differential medium
A method of spreading of bacteria on a plate in order to obtain colonies arising from an individual bacterium.
dilution streaking
The generation time of bacteria in culture. The amount of time it takes for the population to double.
doubling time
A transport system that results in a net movement of charged molecules across a membrane.
electrogenic
A transport system that does not result in any net change in charge across the membrane.
electroneutral
A vesicle formed from the pinching in of the cell membrane.
endosome
A growth solution for fastidious bacteria, consisting of complex media plus additional components.
enriched medium
A compound that an organism cannot synthesize and must acquire from the environment in order to survive.
essential nutrient
A thick extracellular matrix of polysaccharides and entrapped materials that forms around the microbes in a biofilm.
exopolysaccharide (EPS)
A phase in bacterial cell culture when bacteria are growing at their maximal possible rate given the conditions, usually exponentially.
exponential phase
A device that can count cells and sort them based on differences in fluorescence.
fluorescence-activated cell sorter (FACS)
In sporulation of gram-positive bacteria, the smaller cell compartment formed through asymmetrical cell division; it develops into the endospore.
forespore
The species-specific time period for doubling of a population (for example, by bacterial cell division) in an given environment, assuming no depletion of resources.
generation time
The activation of a dormant spore to generate a vegetative cell.
germination
The movement of cells individually or as a collective over surfaces using pili
gliding motility
A form of active transport in which the transported molecule is modified after it enters the cell, thus keeping a favorable inward concentration gradient for the unmodified extracellular molecule.
group translocation
A compound needed for the growth of only certain cells.
growth factor
The rate of increase in population number or biomass.
growth rate
An organism that relies on external sources of organic carbon compounds for biosynthesis.
heterotroph
A phase of slow growth or no growth right after bacteria are inoculated into new media.
lag phase
A differential, selective medium that selects for gram-negative bacteria and can differentiate between lactose fermenters and non-fermenters.
MacConkey medium
A nutrient an organism needs in large quantities.
macronutrient
The number of organismal generations per unit time, k.
mean growth rate constant
Energy stored as an electrical voltage difference across a membrane.
membrane potential
A small colony of bacteria only visible with the aid of a microscope.
microcolony
A nutrient that an organism needs in small quantity, typically a vitamin or a mineral.
micronutrient
The orderly replication and segregation of eukaryotic chromosomes, usually prior to cell division.
mitosis
An organism that can switch among metabolic strategies, such as heterotrophy and phototrophy, depending on the environmental conditions.
mixotrophic
The larger cell that forms during the asymmetric cell division leading to spore formation. The mother cell will engulf the forespore.
mother cell
A fungal hypha that projects into the air (aerial mycelium) or into the growth substrate (substrate mycelium).
mycelium
The oxidation of reduced nitrogen compounds to nitrite or nitrate
nitrification
A bacterium that can reduce diatomic nitrogen gas, N2, into ammonium ion (NH4+) .
nitrogen-fixing bacterium
A measure of how many particles are suspended in a solution based on light scattering by the suspended particles .
optical density
A substrate-specific carrier protein in the membrane.
permease
A form of endocytosis in which large extracellular particles are brought into the cell.
phagocytosis
A large intracellular vesicle that forms as a result of phagocytosis .
phagosome
A group translocation system that uses phosphoenol pyruvate to transfer phosphoryl groups onto the incoming molecule.
phosphotransferase system (PTS)
Organisms that perform photosynthesis, using light energy to reduce carbon dioxide.
photoautotroph
The reduction of carbon dioxide using light as an energy source.
photoautotrophy
The production of energy by the photolysis of organic compounds.
photoheterotrophy
Obtaining energy from chemical reactions triggered by the absorption of light.
phototrophy
A form of endocytosis in which only extracellular fluid and small molecules are brought into the cell.
pinocytosis
Isolated cells, growing individually in a liquid without connections to other cells
planktonic cells
Also known as a Petri dish, a round, shallow-sided container into which molten agar is poured and subsequently cooled
pour plate
A culture containing only a single strain or species of microorganism. A large number of microorganisms all descended from a single individual cell.
pure culture
The ability of bacteria to sense the presence of other bacteria via secreted chemical signals called autoinducers.
quorum sensing
A medium that allows the growth of certain species or strains of organisms but not others .
selective medium
A high-affinity iron binding protein used to scavenge iron from the environment and deliver it to the siderophore-producing organism.
siderophore
A method to grow separate bacterial colonies by plating serial dilutions of a liquid culture.
spread plate
A period of no net increase in replication that follows the exponential growth phase.
stationary phase
An extra-cytoplasmic protein that binds specific substrates and delivers them to their cognate uptake ABC transporters.
substrate-binding protein
A transport protein where the molecules being transported move in the same direction across the membrane.
symport
A bacterial growth solution that contains defined, known components
synthetic media
A continuous culture device that can measure optical density and through changing culture flow rates, maintain a specific cell density.
turbidostat
A type of bacterial movement on solid surfaces where a specific pilus extends and retracts.
twitching motility
An organism that can replicate, for instance by forming a colony on an agar plate.
viable
An organism that is metabolically active but can not replicate to form a colony on a plate by current means of culture. Also called a dormant cel
viable but nonculturable
An organism that grows fastest in acid (generally defined as below pH 5).
acidophile
The use of oxygen as the terminal electron acceptor in an electron transport chain. A proton gradient is generated and used to drive ATP synthesis.
aerobic respiration
An organism with optimal growth in alkali (generally defined as above pH 9).
alkaliphile
The use of a molecule other than oxygen as the final electron acceptor of an electron transport chain.
anaerobic respiration
A molecule that can kill or inhibit the growth of selected microorganisms.
antibiotic
The removal of pathogens from living tissues.
antisepsis
An agent that kills bacterial cells.
bactericidal
An agent that inhibits the growth of bacterial cells.
bacteriostatic
An organism that requires high pressure to grow.
barophile
The use of microbes to detoxify environmental contaminants.
bioremediation
The length of time it takes for a treatment to kill 90% of a microbial population, and hence a measure of the efficacy of the treatment.
decimal reduction time (D-value)
The removal of pathogenic organisms from inanimate surfaces.
disinfection
A microchip containing short DNA sequences corresponding to all the open reading frames in an organism affixed to specific locations. It can be used to measure the amount of specific mRNA molecules transcribed in cells.
DNA Microarray
A collection of membrane proteins that converts the energy of redox reactions into a proton potential.
Electron Transport System (ETS)
A sudden increase of a formerly limiting nutrient in an aquatic environment, leading to overgrowth of algae and grazing bacteria and subsequent oxygen depletion.
Eutrophication
An organism that only grows in an extreme environment; that is, an environment including one or more conditions that are "extreme" relative to the conditions for human life.
Extremophile
An organism that can grow in the presence or absence of a given environmental factor, such as oxygen.
facultative
An organism that can grow either in the presence or absence of oxygen.
facultative aerobe
The production of ATP via substrate level phosphorylation, using organic compounds as both electron donors and electron acceptors.
fermentation
A substance that kills cells but not spores.
germicidal
An organism that requires a high extracellular sodium chloride concentration for optimal growth.
halophile
A coordinated response of cells to higher than normal temperatures. It includes changes in the membrane and expression of heat shock genes.
heat shock response
An organism with optimum growth at extremely high temperatures (generally considered as above 80°)
hyperthermophile
An air filtration appliance that removes pathogenic microbes from within the cabinet.
laminar flow biological safety cabinet
A method to freeze-dry microbes or food for long term storage.
lyophilization
An organism with optimal growth between 20°C and 40°C.
mesophile
An organism that requires oxygen at a concentration lower than that of the atmosphere, and can not grow in high oxygen environments
microaerophilic
An organism with an optimal growth range in environments between pH 5 and 8.
neutralophile
An organism that can only grow in environments containing extremely low concentrations of organic nutrients.
oligotroph
A measure of the number of solute molecules in solution.
osmolarity
The heating of food at a temperature and time combination that will kill spores of Mycobacterium tuberculosis and Coxiella burnetii.
pasteurization
A test of the ability of a disinfectant to kill bacteria; the higher the coefficient the more effective the disinfectant.
phenol coefficient test
An organism that requires high pressure to grow.
piezophile
A food or nutritional supplement that contains live microorganisms and aims to improve health by promoting beneficial bacteria.
probiotic
An organism with optimal growth at temperatures below 20°C.
psychrophile
The destruction of all cells, spores and viruses on an object.
Sterilization
An organism that performs aerobic respiration and can only grow in the presence of oxygen. Also uses oxygen as a terminal electron receptor.
Strict Aerobe
An organism that cannot grow in the presence of oxygen.
strict anaerobe
An organism adapted for optimal growth at high temperatures, usually 55°C or higher.
thermophile
A technique to separate proteins based on differences in charge and molecular weight.
two-dimensional polyacrylamide gel electrophoresis (2-D PAGE, 2-D gels)
A measure of the water that is not bound to solutes and is available for use by organisms.
water activity
Anaerobes that conatain _____ respire, but rely on other terminal electron acceptors than oxygen
cytochromes
What is an oligotroph?
Organisms with a high rate of growth at extremely low organic substrate concentrations.
-majority of microbes found in nature.
Built the first usable British compound microscope...
Robert Hooke
Developed a single lens microscope capable of viewing bacteria...
Antoni van Leeuwenhoek;

his lenses were stronger than Hooke's
Proved that spontaneous generation was wrong for maggots, but not able to do so for microbes...
Francesco Redi
Improved upon Redi's experiment by boiling the meat prior to sealing it in a container...
Lazzaro Spallanzani
Founder of professional nursing...
Florence Nightengale
Discovered that fermentation is caused by living yeast...
Louis Pasteur
Using a swan-necked flask he showed that spontaneous generation was false even when medium is exposed to air...
Louis Pasteur (last nail)
Discovered the fundamental property of chirality...
Louis Pasteur
The first person to recognize the significants of attenuation...
Louis Pasteur
This antibiotic stops the formation of the peptide cross-link in the NAG-NAM sequence of the cell wall.
Penicillin
One of the fundamental laws of physics (entropy) seems to work against the development of life since cells are...
highly ordered structures
The ________ is a way of stating that the chemical foundation for life is the same for all forms of life.
Unity of Biochemistry
Phylogeny that is based upon comparisons of homologous anatomical structures provides a whole-animal perspective of evolution while the use of molecular chronometers of evolution provides a....
cellular perspective
16S ribosomal RNA (rRNA) is used as a...
molecular chronometer

-due to it being ubiquitous, having universal function, and can be aligned
While there are approx. 5,000 currently recognized species of bacteria, it has been predicted that the are more than 500,000 bacterial species... why?
99% of the bacteria found in nature cannot be cultivated in the laboratory
An intact cell membrane is essential for...
cell viability, electron transport, use as a permeability barrier to most molecules and ions
What is meant by "fluid mosaic" ?
The cell membrane properties provided by lateral diffusion of phospholipids and the presence of numerous integral proteins.
The most thermostable cell membrane would be expected to consist of a...
diglycerol tetraether monolayer (found in Archaea)
skirt (s)
Юбка (и) f.
Bacteria are capable of faster nutrient uptake rates than eukaryotic cells because...
they have a larger surface to volume ratio

-cell volume increases faster than surface area. This leads greater nutrient need, but less efficient means of obtaining nutrients
The peptidoglycan of a Gram-negative cell is linked to the outer membrane by...
murein lipoprotein
Gram negative endotoxin is the
Lipid A component of LPS
What is the primary function of the capsule?
avoidance of phagocytosis
This portion of Gram negative bacteria is responsible for their resilience to bile salts and certain antibiotics...
the outer membrane
Bacterial porins are found only in _____________
the outer membrane of gram negative bacteria
What can poly-B-hydroxybutyrate be used for?
biodegradable plastic
What is the only tried and true method of killing endospores?
autoclaving
Which property distinguishes cellular differentiation in Bacillus from that of Caulobacter?
Bacillus gives rise to a dormant cell type (for survival); Caulobacter gives rise to a specialized type of cell (for dispersion).
Used x-ray micrograph to produce the first image of the b-form DNA double-helix...
Rosland Franklin
What is the typical size of a eukaryotic cell?
10-100 micrometers in diameter
What is the typical size of a prokaryotic cell?
1-10 micrometers in diameter
This device resolves images based on their absorption of light.
Light Microscope
The device uses scatters an electron beam from metal-coated sfc of an object, generating an appearance of 3-D Depth
Scanning Electron Microscope
This device sends an electron beam through an object, where electrons are absorbed by a electron-dense metal skin
Transmission Electron Microscope
How did eukaryotes arise?
Their DNA is similar to Archaea and their mitochondrial DNA is similar to bacteria; endosymbiont theory suggests that respiratory bacteria were engulfed by eukaryotes because it provided mutual benefit.
What was the most important scientific discovery of the 20th century?
1000's of genomes sequenced
________ are unique in that they have an elaborate spiral structure with internal axial filaments
Spirochets

-cause diseases such as syphillis and lyme disease
Bacterial cells are best resolved by _______ and ________
electron and fluorescence microscopy
Uses van der Waals forces between a probe and an object to map the 3D topography of an object.
Atomic Force Microscopy (AFM)
Atomic Force Microscopy (AFM)
Uses van der Waals forces between a probe and an object to map the 3D topography of an object.
Detects the interference pattern of x-rays entering the crystallattice of a molecule
X-Ray crystallography
This is used by researchers to build computational models of nucleic acids, ribosomes, etc.
x-ray crystallography
This type of imaging provides structural information based on the magnetic properties of atomic nuclei.
Nuclear Magnetic Resonance (NMR)
Why is chitin brittle and peptidoglycan flexible?
helicity and covalent cross-linking
List the 8 stages (includes 0 stage) of sporulation...
Stage 0: Decision to use one of two polar division sties

Stage 1: DNA extends into an axial filament.

Stage 2: Septum forms near one pole separating forespore from the mother cell

Stage 3: Mother cell engulfs the forespore, surrounding it with a second membrane.

Stage 4: Chromosomes of the mother cell disintegrate.

Stage 5: Forespore develops a cortex layer of peptidoglycan between original forespore membrane and the membrane from the mother cell; layers of coat proteins are deposited in the outer membrane

Stage 6: Synthesis of dipicolinic acid and incorporation of calcium into spore coat.

Stage 7: Mother cell (sporangium) releases the spore.
What is the purpose of dipicolinic acid in stage 6 of sporulation?
Important in maintaining dormancy and promoting spore dehydration... a characteristic that makes the spore heat resistant
What triggers sporulation in Bacillus Subtilis?
Starvation
What is the purpose of the peptidoglycan cortex layer formed during sporulation?
Provides heat resistance and helps maintain dormancy
List two of the primary qualities that allow spores increased survivability...
-- 10-30% of the vegetative cell's water content... increased heat resistance

-- small acid soluable proteins that bind to and protect DNA from damage by ultra-violet light and various toxic chemicals
What are some key differences between gram-positive and gram-negative cells?
Gram-positive:

- No LPSs
- Thicker Cell Wall
- Thinner periplasm
- No Outermembrane
- Teichoic Acids within the peptidoglycan for strength

Gram-negative:

- LPSs
- Outer Membrane... with porins
- thin layer of peptidoglycan

- murein lipoprotein bonded betweem outer membrane and peptidoglycan
- thicker periplasm
- no teichoic acids
What is the basic make up of an LPS?
Modified phospholipid
-glucosamine dimer condenses with two fatty acid side chains
--totals to four
- Each glucoseamine contects to a phosphate
- One of the two glucoeamines is attached to a core polysaccharide
-Core polysaccharides extend to the O-Polysaccharides
--chain of as many as 200 sugars
--may be longer than the cell
--resists phagocytosis
What does the lipid-A portion of a LPS consist of?
Glucosamine phosphate dimer and fatty acid side chains
What four structures make up a LPS?

(top to bottom)
-O-poly saccharide
-Core polysaccharide
-Glucosamine phosphate dimer
-Fatty acids
Bacterial equivalent of cholesterol. Pentacyclic hydrocarbon derivative.
Hopanoids
--strengthens bacterial membranes
--found in bacteria that make ethanol
Basic Make Up of a phospholipid...
- Phosphoryl head group (charged, polar, hydrophilic)

-Glyceral derivative

-Fatty acid side chains (uncharged, non-polar, hydrophobic)
Bacteria and Eukaryotes have _____-linked fatty acids.
ester
Archaea have _____-linked fatty acids.
ether
Why do Archaea have ether-linked fatty acids instead of ester-linked fatty acids?
ether is a more stable compound... Archaea live in harsh environments and require a strong/ flexible membrane.
What feature other than ether-linkage allows for greater membrane strength in Archaea?
The hydrocarbon chains are branched terpenoids...
--every fourth carbon extends a methyl branch
--this feature limits the movement of hydrocarbons creating a more rigid structure; increases the number of covalent bonds
The fluidity of the cell membrane depends, in part, on the _____ and ____ composition...
Phospholipid and Fatty Acid
How is a proton gradient produced?
Membrane proteins use energy from respiration to pump hydrogen ions across the cell membrane (against concentration gradient)... leads to more protons outside the cells than inside... generates PMF
PMF is used to create _____.
ATP.... ATP synthase uses PMF for energy.
What is the advantage of kinked (unsaturated) fatty acid chains?
Kinked chains do not pack as tightly and make the membrane more fluid... this is advantagous when the bacterial cell enters a cold environment... bacteria respond to environmental conditions by increasing or decreasing production of unsaturated phospholipids... some bacteria convert the kinked FAs to cyclopropane when the membrane requires stiffening.
Consists of parallel polymers of disaccharides cross-linked with peptides of four amino acids.
peptidoglycan
NAG = ___________
N-acetylglucosamine
NAM = ___________
N-acetylmaramic acid
Peptide Cross-Links:

How are they formed?
The lactate group of the NAM forms an amide link with the amino acid terminus of a short peptide (containing 4-6 amino acids residues)
The second amino acid group of m-diaminopimelic acid (DAP) is needed to form a cross-link w/ the ______ of of D-alanine from the neighboring peptide.
COOH
DAP links to _______________.
the COOH of D-alanine
What is the composition of the tetrapeptide from left to right (NAM on left).
L-alanine -- D-glutamic acid -- m-diaminopimelic acid -- D-alanine
What do Lysozymes attack?
cut the bond between NAG and NAM... thus destroying the cell wall.
Why is it beneficial for the cell wall to be both flexible and rigid?
-- Flexibility allows the cell to survive in harsh shear conditions

-- Rigidity provides resistance against the effect of osmotic pressure (turgor pressure).
Crystalline layer of thick subunits cosisting of protein or glycoprotein. Additional layer for protection.
S-Layer

-highly ordered arrangment
Reductive evolution often results in the loss of this structure.
S-Layer
Why is the cell wall a good target for antibiotics?
Eukaryotes don't have cell walls... prevents harm to host.
Where does penicillin attack?
It poisons the peptide cross-link in the cell wall
Mycolic acid (seen in the cell wall of mycobacteria) serves what function?
It makes the surface of the bacteria waxy which, in turn, enhances the resistance against phagocytosis by macrophages
The synthesis of arabinogalactin (in tuberculosis causing mycobateria) can be inhibited with the use of what drug?
ethambutol
How does the outer membrane remain intact outside the cell wall?
There is a hydrophobic link between the outer leaflet and the inner leaflet. Also, the inner leaflet is linked to the peptidoglycan via a peptide bond between murein lipoprotein and the tetrapeptide of NAM.
O-polysaccharides repeat ____ units.
40
Porins (OMPs)
-Function?
-Basic Structure
- Form channels through the outer membrane

- Excludes hydrophobic molecules

-Typically Trimers (beta-barrels)
Porins (OMPs)
-Physical Properties?
- 600-700 MW
-Charged (hydrophilic) molecules
Cytoskeletal Proteins:

1. FtsZ

2. MinD

3. MreB

4. CreS

5. MukB
1. FtsZ
--- Forms a "Z-ring" essential for cell septation
--- Localized to the equator by MinD
---Contractile Protein

2. MinD
---Oscillates in rings from pole to pole

3. MreB
---Strengthens the shape of rod cells
---Forms a coil inside rod-shaped cells (actin)

4. CreS (crescentin)
---Curves the inner side of crescent shaped bacteria

5. MukB
---motor protein
---elongates cell
---mutations of MukB causes inproper cell septation
This protein forms a "z-ring" and is essential for cell septation.
FtsZ
This protein oscillates in rings from pole to pole inside the cell and is responsible for localizing FtsZ to the equator.
MinD
This protein strengthens the shape of rod cells by forming a coil inside the cell.
MreB
This protein is responsible for the the curved shape of crescent cells.
CreS
This motor protein is responsible for the elongation of the cell.
MukB
All domains (loops of DNA) connect to a central point known as _____________.
the origin of replication (ori)
The ___________ is attached to the cell envelope near the cell's equator and between the two poles. It is important during replication.
Origin of replication (ori)
There are approx. ___ domains in a bacterial cell.
50
In order to fit all the DNA inside the cell it has to be ________.
supercoiled
Supercoiling is generated by enzymes such as _____ and maintained via _____________.
gyrase; DNA-binding proteins
_______ is a major target for antibiotics such as quinolones (treat pneumonia).
Gyrase... assists with supercoiling.
In bacteria, the direction of extra turns opposes the natural twist. This is called a __________.
Negative superhelical turn...

Positive superhelical turns are seen in archaea and cause the DNA to be wound more tightly, thus making it more stable.
DNA-binding Proteins:
Prokaryotic DNA is condensed further by winding around DNA-bind proteins... allows for better organization and more stability
What is meant by coupled transcription-translation?

Describe the process.
In bacteria, the two processes occur simultaneously. This allows for increased rate of replication.

RNA polymerase binds to the DNA during DNA replication and begins transcribing the sequence to an mRNA strand. As the mRNA strand is transcribed, ribosomes attach to the mRNA and begin translating the code into amino acids (which form peptide chains).
Transcription and translation take up _____ of the cell's energy.
90%
Ribosomes convert the ______ into ___ amino acids (#).
4 letter mRNA code into 20 amino acids
Each amino acid is brought by ______ to fit into the acceptor site within the ribosome.
tRNA...

the acceptor site is sandwiched b/t the 30S and 50S subunits.
DNA Replication:

Describe the process.
At the ori the DNA double helix begins to unzip forming two replication forks (one helix each). At each replication fork DNA is synthesized by a DNA polymerase (2 for each fork = 4 total = 2 replisomes). The DNA helix of each replication fork is unzipped by helicase, forming a leading and lagging strand. The leading strand passes directly through the DNA polymerase while the lagging strand is aided by primase (generates RNA primer). The process is bi-directional and ends once the termination sequence is copied and septation occurs.
What are phycobilisomes?
A protein complex in cyanobacteria that is anchored to thylakoids. Uses light that is inaccessible by chlorophil for photosynthetic reactions. Detects shorter wavelengths which makes it useful in deeper water.
What is a type IV secretion system?
it is similar to a sex pilus... helps cells attach to prey
What is a Type III secretion system?
similar to a flagellar motor... seen in E.Coli. It is like a molecular syringe through which a bacterium can inject proteins into eukaryotic cells.
There are _____ types of secretion systems.
6
Secretion systems are
very small, needle-like, structures that inject receptors into a cell's sfc and attach via that site

essential for bacterial pathogenicity
Peritrichous Flagella =
flagella randomly distributed all around the cell
Lophotrichous Flagella =
flagella attached to one or both poles
Monotrichous Flagella =
Single flagellum attached to one pole
Define Flagella
Long, hollow, helical protein filaments

-tip growth
- attached at cell poles or over the whole cell
-arrangement is characteristic of species
Amphitrichous Flagella =
one flagellum at each pole
In flagella, attractants cause ________ rotation.
counter-clockwise... causes the cell to move forward
In flagella, repellents cause _________ rotation.
clockwise... flagella fly apart; causes the cell to "tumble"
All life requires ______ and _____.
carbon and energy
___________ drives bioenergetics.
electron flow
Uses carbon dioxide as a carbon source.
Autotroph
Uses pre-formed organic molecules as a carbon source.
Heterotroph
Uses light energy to excite electrons, thus obtaining usable energy
Phototroph
Uses chemicals as an energy source.
Chemotroph
Uses an inorganic molecule as electron donor.
Lithotroph
Uses an organic molecule an an electron donor
Organotroph
E. Coli is a
ChemoHeteroOrganotroph
What major elements are required for microbial growth?
Carbon, Oxygen, Hydrogen, Nitrogen, Phosphorus, Sulfur
What ions are necessary for protein function? Thus, cell growth.
Mg2+, Ca2+, Fe2+, K+
What trace elements are necessary for enzyme function? Thus, cell growth.
Zinc, Selenium, etc.
What are the Macronutrients?
major elements required in cell macromolecules.
-- C, O, H, N, P, S

And, ions necessary for protein function

-Mg2+, Ca2+, Fe2+, K+
What are Micronutrients?
Trace elements necessary for enzyme function.

-Zinc, Selenium, etc.
Examples of growth factor requirements:
Amino Acids, Nucleotides, Vitamins, etc.

-different organisms require different growth factors
3 Classifications of Growth Factor Requirements:
1. Prototroph (E.Coli): Can take care of its own needs

2. Auxotroph: Requires specific compounds as a growth factor

3. Fastidious: Does not have the ability to produce own nutrients
4 common types of culture media and some of the characteristics.
LB (complex): can't define what is in it. Cultures many GN and GP bacteria

M9 Medium (defined): Cultures GN bacteria (such as E.Coli). Recipe is possibly missing MgSO4.

Azotobacter medium (defined): Cultures azotobacter. Obtains ammonia from the air (N source).

Sulfur oxidizers (defined): Cultures Thiobacillus Thiooxidans. Gets energy to oxidize sulfur in growth media. Chemolithoautotroph
What are the steps of the Nitrogen Cycle? (3)
1. Nitrogen (N2) is fixed into 2 molecules of ammonium.

2. Ammonium is the nitrified into Ammonia

3. Ammonia is then denitrified into Nitrogen (N2)
What are the 5 primary types of nutrient transport systems?
1. Passive Diffusion

2. Facillitated Diffusion

3. Active Transport

4. ABC System

5. Group Translocation System
---i.e. Phosphotransferase Uptake System (PTS)
What are two examples of coupled transport systems and are they active or passive?
Antiport and Symport; both active
Characteristics of Passive Diffusion:
- Some gases flow freely through membranes
---O2 and CO2
---follows gradient of solute
Characteristics of Facilitated Diffusion:
Transporters pass solutes into/out of the cell along concentration gradient

--no energy cost
--Saturatable Kinetics: if there are more nutrients than transporters, transporters are saturated
----slows nutrient uptake
ABC Systems use ___________ to obtain nutrients from the periplasm.
Substrate-bind proteins
The use of substrate-binding proteins is highly beneficial due to...
their increased affinity for specific substrate... thus, they are more capable/ efficient in obtaining substrate than normal active transport systems. Downside: they use a lot of energy.
Advantage of using symports/antiports...
Although they are less efficient than ABC systems, they use less energy.
Advantage of using a group transloaction system...
GT systems such as PTS use energy from other molecules to attach compounds to specific substrate (i.e. in PTS glucose becomes glucose-6-phosphate). Thus, the solute concentration gradient remains constant. Plus, while it uses energy to chemically alter the solute, there is no net expenditure of energy.
Three types of media
1. Selective Media

2. Differential Media

3. Combined Media (e.g. Lactose-MacConkey media)
Characteristics of Selective media...
-Only organisms of interest will grow.
-i.e. inclusion of antibiotics/ growth inhibitors
Purpose of differential media...
organism of interest easily distinguished
Characteristics of Lactose-MacConkey medium
--both selective and differential

--complex nutrients

--bile salts are selective for GN

--Neutral red:
lactose fermenters are red non-fermenters are white

--crystal violet: strong fermenters have 'halo"
Petroff-Hauser Chamber
--Counts cells directly
--Gives accurate number
--Can't tell if cells are alive or dead
Disadvantage of using a Petroff-Hauser Chamber?
can't tell if cells are alive or dead; must use stain
Coulter-Counter
--Direct counting w/o microscope
--Microbial culture is forced through a small oriface, through which flows an electrical current
--measures resistance as each cell is passed through and thus counts each cell; also can't tell if alive or dead.
Spectrometry
Uses spectrophotometer
--measures the optical density (shadow of bacteria)
--Gives rapid measurement
--can't tell if cells are alive or dead
--solution must be 10^7-10^10 cells/ml
--drawback: cell density varies with growth age
Plate Counts
Viable counts:
--Counts only cells that are able to reproduce (CFUs = colony forming units)
--Drawback: requires time to form colonies (usually overnight)
4 phases of the growth cycle
1. Lag Phase

2. Log Phase

3. Stationary Phase

4. Death Phase
Steps in the formation of a biofilm:
Step 1. Environmental signals (i.e. pH, Fe concentration, temp, etc.) cause planktonic cells to begin attaching to inanimate sfcs (by means of flagella, pili, fimbria, LPSs,etc).

Step 2. The cells begin coating the sfc with organic compounds to allow for more cells to attach

Step 3. The cell begin spreading over the sfc via "twitching motility"

Step 4. Quorum sensing is used to reach proper numbers of cells and to signal cells to attach to one another.

Step 5. Cells fortify their position using EPSs (exopolysaccharides), a thick extra-cellular matrix used for protection

Step 6. Once film matures, the matrix forms channels through which nutrients can flow.
Characteristics of a biofilm:
Cells act together as one (can be several different species)

Cells signal each other (quorum sensing)

Benefits cells by preventing dispersion and preventing penetration of antibiotics
Cell Differentiation:

Heterocysts
-In cynobacteria
-Created to solve the problem of simultaneous CO2 fixation (to make O2) and Nitrogen fixation (to make ammonia).
---Nitrogenase is sensitive to O2
---Heterocysts are photosynthetic cells with no capacity to fix CO2 and a limited permeability to O2
---Used soley for nitrogen fixation
---Every tenth photosynthetic cell is a heterocyst
Cell Differentiation:

Myxospores
Seen with Myxococcus

Form as a result of starvation

Form inside fruiting body
--multicellular structure
Cell Differentiation:

Actinomeycetes includes steps
Step 1. Formation of substrate mycelium in nutrient righ environment

Step 2. After 48-72 hours, bld genes cause the production of aerial hyphae

Step 3. When growth stops, the compartment segments. Each segment changes shape and its wall thickness to become dessication-resistant spore
List 6 environmental limits on microbial growth
Temperature, pH, Water Activity, Nutrient Limitation, Pressure, Oxygen
List the 4 microbe temperature classifications
Psychrophiles: (cold) 0-20 degrees celsius

Mesophiles: 12-45 degrees celsius

Thermophiles: 40-80 degrees celsius

Extreme Theremophiles: 65-113 degrees celsius
List the 3 microbe pressure classifications
Barotolerant: grow at high, but not very high pressure

Barosensitive: Die at high pressure; most typical bacteria, all mammals

Barophiles: Adapted to high pressures; up to 1000 atm; apparently no pressure response.
What is the purpose of heat shock response?
Helps prevent proteins from denaturing

Chaperones help refold denatured proteins

Induced by stressors that denature proteins: heat, high salt, drying
Grow rate follows Arrhenius Plot...
2x growth rate per 10 degree K

example: 20 degrees K = growth rate of 4

Plot displays growth rates at Cardinal temperatures: min, max, optimum
Measure of water that is usable for growth...
Water Activity
Osmolarity is _________ related to water activity.
inversely; more solutes = decreased water activity
High osmolarity reduces or increases water availability?
reduces
What are mechanosensitive channels?
channels that relieve stress (caused from cell being in hypotonic solution) by allowing solutes to leak out... this decreases the solute concentration inside the cell and reduces the osmolarity.
What can a cell do to minimize stress when in a hypertonic solution?
they can synthesize solutes that increase the internal osmolarity... this brings reduces the osmolarity and increases the water activity
Increased osmolarity to the point of osmotic shock leads to...
similar to heat shock response: increased synthesis of chaperones and alteration of membrane pore composition
What are osmolytes?
Compatible solutes that are synthesized by the cell when stranded in a hypertonic medium... increases water activity and decreases osmolarity
What are Halophiles?
A type of archaea that evolved to require high salt concentration (NaCl).

-requires 2-4 Molar (10x seawater)
Why is pH a growth limiting factor?
Enzymes only work in a narrow pH range.

Amino acids must have correct charges
--pH levels alter the H+ concentration
List the 3 microbe pH tolerance classifications
Neutralophiles: grow at pH 5-8; include bacteria in gut

Acidophiles: grow at pH 0-5; some grow in stomach acid or sulfuric acid springs

Alkalophiles: Grow at pH 9-11; found in soda lakes
How does the cell regulate its pH when in an acidic environment?
Proton circulation; by continuously transporting protons out of the cell by various methods
How do alkalophiles live in such highly basic conditions?
Instead of using H+ for ATP synthase, they are designed to use Na+. The gradient is maintained in the same fasion... Na is pumped out, which generates a sodium motive force. A Na/H antiporter is used to keep the internal pH lower than outside.
(High H+ concentration/ low Na concentration)
Why do microbes die at a logarithmic rate?
Not all cells are contacted at the same time and cells differ in health/ growth stage
What is the D-Value?
A measure of the efficacy of a given agent or condition... measures the length of time it takes an agent to kill 90% of the population
What is the D-value effected by?
Population size, population concentration, agent concentration, duration of exposure
Process of reducing the microbial population to safe levels
Sanitation; involves clean object then disinfecting it
The process of heating a particular food to a specific temp for long enough to kill Mycobacterium tuberculosis and Coxiella burnetti.
Pasteurization
2 types of pasteurization:
LTLT: low temp/long time-- heat to 63C for 30 min.

HTST: 72C for 15 sec

UHT: ultra-high temp--150C for 3 seconds
-------kills all bacteria
What device uses temperature and pressure to kill bacteria and endospores?
Autoclave: 121C, 2 atm, 20 min.
4 factorsw that determine the efficacy of a chemical agent:
Presence of organic matter

Type of organisms present

Corrosiveness

Stability, odor, and sfc tension
What is the Phenol Coefficient Test?
based on the highest dilution of a disinfectant that will kill all the bacteria in a test sample after 10 minutes of exposure
What antibiotic inhibits transpeptidase and causes growing bacteria to lyse?
Penicillin
What is phage therapy?
the use of bacteriophages in the treatment of disease... bacteriopages are viruses that prey on bacteria.
What is a probiotic?
a food or suppliment that contains live microorganisms and improves intestinal microbial balance.
What are the three types of agents used in controling microbial growth?
Physical agents (temp, pressure, irradiation, filtration, etc.)

Chemical Agents (i.e. disinfectants, soaps, detergents, etc.)

Biological Agents (i.e. probiotics, phages, etc.)
What is the z-value?
the measure of much more heat is required to reduce the D-value to 1/10 its original value.
Test: Fulfillment of Koch's postulates required the invention of...
pure culture technique
Test: The concept of a common ancestor of all living things is supported by both ________ and __________.
endosymbiosis and unity of biochemistry
Test: The membranes of extremely thermophilic Archaea often consist of:
Diglycerol tetraether monolayer
Test: The spherical shape of cocci can be explained by the absence of which cell division and cytoskeletal protein?
MreB
Test: The cross-links in peptidoglycan are made between which two groups?
COOH of D-alanine and NH2 of m-DAP
Test: Which of the following is a function of the bacterial capsule? (think primary function)
avoiding phagocytosis
Test: What is the advantage of an active transport system (e.g. symport) over an ABC system?
Consumes less energy
Test: Bacterial endospores resist kill by all, but which of the following treatments (easy)
autoclave
Test: Balanced growth refers to the doubling of ____ during each generation?
Cell size, mass of DNA, ribosomes, cell number

All of the above