Term
| How is selective permeability achieved? |
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Definition
-By the use of substrate-specific carrier proteins (permeases) in the membrane
-aid from dedicated nutrient-binding proteins that patrol the periplasmic space
-through the action of membrane-spanning protein channels, that discriminate between substrates |
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Term
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Definition
Type of system that uses the concentration gradient of a compound to move that compound across the membran from high to low concentration.
ex. GLpF facilitates h20 and glycerol |
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Definition
| When a transport protein uses free energy from an ion moving down its concentration gradient to drive the transport of a second molecule against its concentration gradient |
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Term
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Definition
Symport- one molecule pushes another molecule down the concentration gradient, same direction
Antiport- the actively transported molecule moves in the opposite direction of the driving ion |
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Definition
| "ATP-binding cassette" tranporter- a super family of energy driven transport systems that are critical for transporting nutrients, always against the gradient |
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Definition
| Chemically alters a substrate during transport so that it will go down the gradient into the cell. |
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Definition
-organisms can move about freely
-useful for studying the growth characteristics of a single strain of a single species (pure culture)
-good for examining growth kinetics and microbial biochemistry at different phases of growh |
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Definition
-usually gelled with agar
-useful for trying to separate mixtures of different organisms as they are found in natural environment or in clinical specimens |
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Definition
| Favor the growth of one organism over another |
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Definition
| expose biochemical differences between two species that grow equally well |
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Term
| Fluorescence-activated cell sorter (FACS) |
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Definition
| an instrument that can measure cell size, identify, and count different populations of cells by detecting the light scatter of a laser passing through the fluorescent labeled cells |
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Term
| Formula for calculating number of generations (n) |
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Definition
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Term
| Formula for growth rate constant (k) |
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Definition
| k= n/t= log10(Nt/N0)/0.301t |
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Term
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Definition
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Term
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Definition
time needed for bacteria to detect their environment, express specific genes, and synthesize components needed to institute rapid growth
a variety of factors determine the length, such as if they are damaged, if they are put on old or new media, complex or minimal media, etc. |
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Term
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Definition
| in a liquid batch culture consists of lag phase, log phase, stationary phase, and death phase |
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Definition
| discovered Archaea in hot springs in 1977, replaced the 5 kingdoms with the 3 domains bacteria, archaea, and eukarya |
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Term
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Definition
| the ability to exchange genetic information by transduction, conjugation or transformation indicates a high level of DNA sequence conservation |
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Definition
| based on morphology, nutritional requirements (phototroph, heterotroph, lithotroph), oxygen requirement, spore formation, cell wall chemistry |
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Definition
| uses classical traits to create a systematic grouping of related bacteria, system of dichotomous keys- separates species on hierarchical series of tests |
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Term
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Definition
| first described microorganisms viewed with compound microscope, coined the term "cell" for basic unit of life |
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Term
| Antoni van Leeuwenhoek (1632-1723) |
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Definition
| first person to see individual bacteria w/ normal microscope, his reports were so detailed we can even determine the species he observed, he used his own microscope with a single lense stronger than Hooke's |
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Definition
| built microscopes that had lenses that corrected for chromatic and spherical abberation and provided good images at up to 1000x magnification |
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Term
| Francisco Redi (1626-1697) |
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Definition
| disproved the spontaneous generation of flies |
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Term
| Lazzaro Spallanzani (1729-1799) |
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Definition
| showed that infusions heated in a sealed glass flask did not produce microbial cells, shoed that microbial cells arose from existing cells by cell fission, (disproving spontaneous generation a little |
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Term
| Louis Pasteur (1822-1895) |
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Definition
| disproved spontaneous generation of microbes with his swan necked flasks experiments |
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Definition
| noticed he couldn't reproduce Pastuer's observations, hypothesized that there were heat resistant microbes, showed repeated boiling and cooling would kill them, process called Tyndallization, also disproving spontaneous generation |
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Term
| Ferdinand Cohn (1828-1898) |
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Definition
| discovered the bacterial structure called an endospore that is resistant to many environmental extremes, what tyndall was killing, disproving spontaneous generation |
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Term
| Theodor Schwann (1810-1882) |
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Definition
| proposed tranformations of matter including fermentation, putrefactions, and liquefactions were caused by microorganisms |
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Term
| Jacob Berzelius, Justus von Liebig, and Friedrich Wohler |
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Definition
| were against Schwann, insisted these were chemical reactions |
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Definition
| solved their argument by showing specific organisms are associated with specific fermentations. discovered anaerobes. |
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Term
| Girolamo Fracastoro (1478-1553) |
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Definition
| proposed that "spores" could transmit disease |
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Term
| Agostino Bassi (1773-1856) |
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Definition
| shoed that a fungal disease killed silkworms in 1836 |
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Term
| Johann Schonlein (1793-1856) |
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Definition
| showed that a fungus causes ringworm |
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Term
| Miles Joseph Berkeley (1803-1889) |
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Definition
| showed that many plant diseases were caused by fungi |
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Term
| Florence Nightingdale (1820-1910) |
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Definition
| A British nurse who founded medical statistics. Showed that more soldiers have died of microbial infections than of wounds in battle |
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Term
| Ignaz Philipp Semmelweis (1818-1865) |
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Definition
| suggested physicians use hand disinfection between seeing patients. Reduced mortality of child bed fever from 35% to 1%, but observations were mostly ignored |
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Term
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Definition
| used pastuer's ovservations to initiate antiseptic surgery in which wounds and instruments were sterilized with carbolic acid |
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Definition
| Finally proved that bacteria caused disease, studied the disease anthrax, noticed that when transferring blood of infected mouse to healthy one they healthy one became infected. Grew the rod shaped bacteria in sterile serum and showed when put in healthy mouse, the mouse also became infected |
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Term
| Casimire Davaine (1812-1882) |
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Definition
| shown that the blood of infected animals contained rod shaped organisms |
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Term
| Friedrich Henle (1809-1885) |
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Definition
| proposed 4 criteria to establish that an agent caused disease, these would be called Koch's Postulates |
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Term
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Definition
1. microbes must be present in every case of the disease
2. microbe must be isolated in pure culture
3. The disease must reappear when organisms from pure culture are injected into an uninfected animal
4. microbe then must be again recovered from the newly infected animal and shown to be the same organism |
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Term
| Golden Age of Microbiology (1850-1900) |
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Definition
many bacterial diseases were identified, improvements in public health, studies on immunology by Pastuer
Discovery of viruses as agents of disease by Dmitry Ivanovsky and Martinus Beijerinck |
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Definition
| introduced practice of smallpox inoculation to europe in 1717 |
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Term
| Edward Jenner (1749-1823) |
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Definition
| deliverately infected patients with matter from cowpox lesions, this process would be called vaccination |
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Term
| Louis Pasteur (immunization) |
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Definition
| developed first vaccines based on attenuated or weakened strains, fowl cholera, ravies. |
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Term
| Development of Pure Culture techniques |
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Definition
Koch developed these techniques to link specific bacteria to specific diseass
Pastuer and Charles Chamberland developed the autoclave which sterilized growth medium at 121 degrees C
Julius Petri invented the petri plate
Angelina and Walther Hesse used agar to make solid medium |
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Term
| Martinus Beijerinck and Sergei Winogradsky |
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Definition
used enrichment culture techniques to isolate bacteria from environment. Found organisms that cycles nitrogen and sulfur
Winogradsky proposed concept of chemolithotrophy in which oxidation reduced inorganic compounds that can be used for energy |
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Term
| Pleomorphism vs. monomorphism |
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Definition
Do a vew bacteria adapt to their environment in many shapes and forms or are their many bacteria with limited variability in form and function
The latter, monomorphism was shown to be true by use of pure cultures |
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Term
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Definition
| developed by Ernst Ruska, reveals internal structure of cells |
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Term
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Definition
developed by Theodor Svedberg
-a key tool of subcellular fractionation is the ultracentrifuge
-high rotation rate produces centrifugal forces strong enough to separate particles by size |
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Term
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Definition
discovered that Penicillium mold generated a substance that killed bacteria
In 1941 Howard Florey and Ernst Chain purified penicillin, the first commercial antibiotic to save lives |
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Term
| Definitions of Magnification, Resolution,and Contrast |
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Definition
Magnification- the extent to which the image of an object is larger than the object
Resolution- quantitative measure of the closest distance between two points at which they are clearly separate entities
Contrast- the ability to distinguish an organism from the background |
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Term
| 3 conditions for electromagnetic radiation to resolve an object |
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Definition
1. Contrast between object and its medium
2. Wavelength smaller than the object
3. detector with sufficient resolution for the given wavelength |
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Term
| Resolution and Numerical Aperture equations |
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Definition
| Resolution = d = λ/N.A. and N.A. = N x sin θ where N is the refractive index of the medium |
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Term
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Definition
Eukaryotes 10-100 micrometers
Prokayotes 0.4-10 micrometers |
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Term
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Definition
| Increases the size of the image but the resolution isn't changed, no new information about the picture can be seen |
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Term
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Definition
| light goes through the specimen to view it. |
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Term
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Definition
Uses scattered light to detect objects too small to be resolved by light rays
advantage- extremely small microbes and thin extracellular structures can be detected
disadvantage- shape of objects isn't resolved, dust particles can obscure image |
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Term
| Phage contrast microscopy |
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Definition
super imposes refracted and transmission light to reveal differences in refractive index patterns
adv- live cells with transparent cytoplasm and organells of eukaryotes can be observed with high contrast
disadv.- phase contrast less effective for organisms with cytoplasm at low refractive index |
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Term
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Definition
confocal laser scanning microscopy, both excitation light and emitted light are focused together
-can visualize cells in 3 dimensions
-allows observation of live microbes in real time |
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Term
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Definition
Sample is coated with heavy metal to absorb electrons
-electric beam and sample are in vacuum
-lenses are magnetic fields |
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Term
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Definition
sample is flash frozen so crystals aren't produced
cryo-electron tomography- generates high resolution models of viruses
-sample doesn't have to be thin-sliced |
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Term
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Definition
| measures van der Waals forces between electron shells of adjacen atoms of the cell surface and the sharp tip |
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Term
| X-ray diffraction analysis |
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Definition
Samples are crystallized, beam is shot at sample and the position of atoms are computed based on the scattered X-rays
-shows 3d form of cell components at atomic level
-helps relate structure to function |
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Term
| How do double bonds affect fatty acid chains of membrane lipids? |
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Definition
If the chain is unsaturated (contains one or more double bonds) and the double bond is cis it creates a "kink" in the oleic acid so that the chains don't pack as tightly and the membrane is more fluid
-some side chains can even form cyclopropane which will stiffen the membrane, this is usually in response to a stress like starvation or acidity. |
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Term
| What else do cells have that stiffen the membrane? |
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Definition
Membranes use planar molecules that fill gaps between hydrocarbon chains to reinforce the membrane.
In eukaryotes these are called sterols, for ex. cholesterol
In bacteria the same function is done by pentacyclic hydrocarbon derivatives called hopanoids or hopanes |
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Term
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Definition
| use a ether link between glycerol and fatty acid instead of an ester link. Ether link is a lot more stable. They also are branched terpenoids. these help strengthen the membrane, but limit movement. Some may even have diglycerol tetraethers, which generate a lipid monolayer. |
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Term
| What can travel across the cell membrane without help from a protein transporter? |
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Definition
Small uncharged molecules, such as O2 and CO2 easily permeate the membrane by diffusion.
Water can diffuse across the membrane through osmosis
Weak acids and weak bases can also diffuse across the membrane and change the pH of the cell. |
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Term
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Definition
| Thick cell wall, contains multiple layers of peptidoglycan, interpenetrated by teichoic acids and a cytoplasmic membrane |
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Term
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Definition
| Thin cell wall, has an outer membrane consisting of lipopolysaccharide and protein, periplasm, one to three layers of peptidoglycan and a cytoplasmic membrane |
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Term
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Definition
| peptidoglycan makes up the cell wall, it helps confer the cell shape and also prevents osmotic lysis. The entire cell wall is a single molecule. |
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Term
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Definition
| on the outside membrane of gram negative cells, have short fatty acid chains, It acts as an endotoxin, and endotoxin is a cell component that is harmless as long as the pathogen remains intact, but when released by a lysed cell, endotoxin overstimulates host defenses. |
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Term
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Definition
| connect outer membrane to cell wall of gram negatives, the major one is called murein lipoprotein |
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Term
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Definition
contains 30 to 50 different proteins in high concentration, hydrolytic proteins to process nutrients (nuclease, proteases, phosphatases)
Binding proteins which transport molecs across membrane
Chemoreceptors that signal to cytoplasm |
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Term
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Definition
| sort of an outer membrane for gram positive bacteria, it is a rigid structure made up of proteins that forms a smooth layer around the cell wall. substances can pass through in either direction |
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Term
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Definition
| firmly attached to cell wall, excludes small molecules, composed of polysaccharide or protein, protects cells from phagocytosis |
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Term
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Definition
Proteinaceous filamentous structures on the surface of bacteria
Fimbriae allow organisms to attach to surfaces including host cells in pathogen-host interactions
Pili are longer appendages, allow bact to mate (sex pilus) or move |
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Term
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Definition
| attachment organelle, membrane-embedded extension of cytoplasm, the en of stalk secretes holdfasts, which are polysaccharides that firmly attach bacteria to an environment that has proved favorable |
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Term
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Definition
| Organelle of mobility in bact., have a helical structure, spin to push or pull bacteria through liquid medium |
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Term
| How are flagellum powered? |
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Definition
| Proton motive force is the energy source for a flagellum, transport about 1000 protons for each revolution |
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Term
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Definition
| DNA must be highly condensed to fit into cell, negative phosphate charges on DNA backbone must be neutralized b polyamine and Mg++, DNA is negatively supercoiled, this condensed form is maintained by small positively charged DNA binding protiens |
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Term
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Definition
| Bacteria and archaea have cytoskeletal proteins, Tubulin homologs are found in both and are involved in cell division, actin homologs are found in both and again involved in cell division and shape |
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Term
| Specialized Structures: Thylakoids, Carboxysomes, and Gas vesicles |
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Definition
Thylakoids- extensively folded intracellular membranes
Carboxysomes- polyhedral bodies packed with enzyme Rubisco for CO2 fixation
Gas vesicles- to increase buoyancy, filled with gases that are dissolved in cytoplasm, water cannot enter |
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Term
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Definition
Polyhydroxybutyrate (PHB) is brroken down to acetyl-CoA when energy is needed, feeds into TCA cycle
Glycogen also used as storage, broken down into glucose-1-phosphate by glycogenolysis, which feeds into glycolytic pathway |
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Term
| Phosphate and sulfur storage |
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Definition
Phosphate stored in the form of polyphosphate can be broken down for use in nucleic acid and phospholipid synthesis
Hydrogen sulfide is oxidezed to sulfur during chemolithotrophy, and stored in globules |
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Term
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Definition
| highly resistant form of bacteria, dehydrated, dormant, resistant to many stresses |
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Term
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Definition
| fix CO2 and assemble into organic molecules (mainly sugars) |
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Term
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Definition
| used preformed organic molecules |
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Term
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Definition
ventry=Ventry[S]ext/KD+[S]ext
ventry is the velocity of entry, Ventry is the maximum velocity of entry, [S]ext is the external concentration of the nutrient, and KD is the dissociation constant of the permease for the nutrient |
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Term
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Definition
| Permease required (transport protein), no energy required, goes down concentration gradient |
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Term
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Definition
| uses permeases and energy source to move nutrients against concentration gradient |
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Term
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Definition
specialized molecules secreted to bind ferric ion (Fe) and transport it into the cell
-iron is released into the cytoplasm and reduced to the more useful ferrous form |
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Term
| Balanced Growth of Bacteria |
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Definition
| state in which bacteria adapted to growth medium and are doubling in biomass accompanied by a doubling in all measureable properties of population (cell number, protein content, DNA, etc.) |
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Term
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Definition
| MreB determines cell shape is homologous to actin and forms a filament like cytoskeleton, also directs synthesis of peptidoglycan prior to cell divison |
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Term
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Definition
| Fts proteins form the divisome, FtsZ forms ring around the center of dividing cell, homolog of tubulin |
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Term
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Definition
| Min proteins align the divisome, others inhibit cell division by preventing stable association of FtsZ, as cell grows longer Min proteins spend more time at ends of cell and allow FtsZ ring to form in the center |
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Term
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Definition
Bactoprenol carries peptidoglycan subunits across membrane, Hydrolases make openings in murein wherethe subunits are added. Transpeptidases carry out crosslinking
good target for antibiotics since eukaryotes don't have peptidoglycan
Transpeptidase inhibited by penicillin |
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Term
| Petroff-Hauser counting chamber |
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Definition
| used to count total number of cells. averages the amount of organisms in each square to find total |
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Term
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Definition
| Particle counter used for any cell, works by detecting change in electrical conductance of a small aperture as fluid containing cells are drawn though |
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Term
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Definition
| decreases absorbance due to light scattering from cells. light scattering depends on size of particle, standard curves must be prepared to compare OD to some other measurement of cell number |
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Term
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Definition
| measure the scattered light by having the phototube at an angle to the incident light, scattered light is measured, more sensitive than absorbance |
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