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79 terms

Microbiology - Test 1

Terms from: *History and Scope of Microbiology * Microscopy * Prokaryotic Cell Structure and Function * Microbial Taxonomy, Evolution, and Diversity * Microbial Nutrition * Microbial Growth
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Poly-ß-hydroxybutyric acid
An inclusion body in prokaryotes that is lipid-like. It stores carbon and can be an energy source. It is found in purple photosynthetic bacteria. Organic.
Glycogen
An internal structure in prokaryotes that is starch-like. It is used to store carbon and is an energy source. Organic.
Volutin
An internal structure found in prokaryotes that is a polyphosphate reservoir. Useful for creating ATP. Inorganic.
Sulfur granules
An internal structure found in prokaryotes. It is an energy and electron source found in puple sulfer photosynthetic bacteria. It is composed of dense regions of elemental sulfur.
Cyanophycin granules
An internal structure found in prokaryotes. It is polymer composed of aspartic acid and arginine. It is used to store nitrogen. It is found in cyanobacteria. Organic.
Carboxysome
An internal structure in prokaryotes that contains Rubisco, which is used for CO2 fixation. It is found in cyanobacteria, thiobacilli, and nitrifying bacteria. Any photosynthetic or chemosynthetic organisms contains this structure.
Magnetosomes
An internal structure in magnetic bacteria. It is not used for storage, but rather allows the organism to orientate itself for navigation towards nutrients. It is composed of dense regions of magnetic structures in the brain of the organism. Aqautic bacteria use it in order to know where the surgace is.
Gas vacuoles
An internal structure in prokaryotes that is made of a single protein and it is impermeable to water but permeable to gas. It allows bacteria to float to the surface, therefore providing buoyancy for aquatic bacteria.
Coccus
Sphere shaped bacteria
Bacillus
Rod shaped bacteria
Vibrio
Comma-shaped bacteria
Spirilla
A spiral-shaped bacteria whose flagella is on the outside.
Spirochete
A spiral-shaped bacteria whose flagella is on the inside.
Pleomorphic
A bacteria that can have many shapes including oval-like.
Appendaged
A bacteria that has extensions on its cell that are long tubes or stalks. These are used for attachment.
Dipicolinic acid
This is found in endospores. Even without it endospores have been found to be heat resistant.
Hopanoid
A steroid-like molecule that can be found in a prokaryote's cytoplasmic membrane.
Mesosome
An internal invagination of the cytoplasmic membrane. It may serve as a site for chromosome attachment during cell division.
Peptidoglycan
A large polymer composed of long chains of alternating N-acetyl-glucosamine and N-acetylmuramic acid residues. The polysaccharides chains are linked to each other though connections between tetrapeptide chains attached to the N-acetylmuramic acids. It provides much of the strength and rigidity possessed by bacterial cell walls
DAP (Daminopimelic acid)
Links to D-alanine directly in gram- cell walls.
Teichoic acid
This molecule is unique to gram+ bacteria. It cnonects peptidoglycan molecules to each other via NAM, therefore acting like a fencepost between NAG and NAM.
Porins
Found only in gram- bacteria. It provides channels for small molecules to pass through.
Lipopolysaccharides
Found in the outermost layer of gram- cell walls. It is degraded by alcohol during staining.
Penicillin
An antibiotic which inhibits peptidoglycan synthesis.
Lysozyme
This enzyme can weaken peptidoglycan strength by breaking the bonds between NAG and NAM. It is a natural antimicrobial found in tears and saliva.
Sec-Dependent Secretion
A type of protein secretion that is found in both gram+ and gram- organisms. It allows things to cross the cytoplasmic membrane but not to the outside.
Type II Secretion
A type of protein secretion that is only in present in gram negatives. It is common in pathogens. It transports cellulases (lysis cells), pectinases (plant cells), proteanses, lipases, and toxins across the outer membrane from the periplasmic space.
Type V Secretion
A type of protein secretion that is only found in gram negatives. Proteins are shuffled from the periplasmic space to the outer membrane. It is possible for sec dependant secretion could be coupled with this type of secretion to transport things from the cytoplasm all the way to the outside of the cell.
ABC Transport (Type I Secretion)
A type of protein secretion only found in gram-. It uses the C-terminal instead of the N-terminal to singnal for recognition of net proteins. It also aids in expelling drugs from the cytoplasm. It spans the cytoplasm to the outer membrane, making sec-dependent transportation unnecessary.
Type III Secretion
A type of protein section that is only in gram-. It transports directly from the cytoplasm to the cell exterior, mkaing sec-dependant secretion unnecessary. It is primarily used by pathogens. It transports toxins, phagocytosis inhibitors, apotopsis promoters and secretion regulatory proteins.
Type IV Secretion
A type of protein secretion found only in gram negatives. It can secrete both proteins and DNA (for conjugation).
Glycocalyx
This structure is not present in all bacteria. It is used for storage, protection, energy (because it is a polysaccharide layer which can be a food source).
Slime layer
A type of glycocalyx that is loose and not organized. It protects aginst drying and biofilm formation.
Capsule
A type of glycocalyx that is thick and tightly bound .It is extrememly organized. It is antiphagocytic and protects against drying. It can be used for attachment because it is composed of sticky polysaccharides. Can have high levels of protein.
Sheath
Type of glycocalyx which is a highly organized external layer. It can be described as a sac that keeps a group of cells together and protects them against disruptions caused by currents.
S-Layers
This cell layer is found in some gram+ and some gram- bacteria, and is common among Archaea. In gram- bacertia is adheres directly to the outer membrane. In gram+ bacteria it is associated with peptidoglycan.
Filament
The part of the flagella that sticks out into the environment. It is hollow on the inside and growth only occurs at the tips.
Hook
The part of flagella that is anchored to the cell wall.
Basal body
The part of the flagella that is embedded in the cytoplasmic membrane. It has a motor for rotation that spins like a propeller.
Fimbriae
Used to attach bacteria to solid surfaces. It is the velcro of the bacterial world.
Pili
A structure that is involved in bacteria conjugation or transport of molecules into or out of the. It allows the transfer of plasmids from one cell to another.
Monotrichous
A term given to a single flagellum located on the end of the cell.
Lophotrichous
Several flagella protruding from one end of the cell
Amphitrichous
The presence of flagella at both ends of the bacterial cell
Peritrichous
Flagella are found around the entire surface of the cell
Passive diffusion
Molecules move from higher to lower concentration. Usually works for smaller molecules such as O2 and CO2 and gases. Very inefficient.
Facilitated diffusion
Works with larger molecules by using carrier proteins. Moves things from higher to lower concentrations. There is a saturation point that can be reached. Can be used to remove waste from the cell. This is not a prominent transport mechanism for nutrients into prokaryotic cells.
Active Transport
Transport of a substance (as a protein or drug) with a carrier protein across a cell membrane against the concentration gradient. Uses energy. Can reach a saturation point. Resembles facilitated diffusion because it uses permeases, has specificity, and is saturable.
Group translocation
A variation of active transport that occurs only in bacterial cells and only with certain molecules. A molecule is transported into the cell and at the same time it is chemically changed into a slightly different molecule. It requires energy, but the chemical modification prevents the molecule from leaving the cell. in a sense it is a trapping mechanism. Phosphorylation ( the addition of a phosphate group) is one variation of how bacteria do this.
Carrier proteins
A permease that spans the cell membrane. It has high specificity, mainly being used by large molecules. The binding of a molecule may change the conformational shape of the permease.
Uniport
A type of active transport that moves only one molecule at a time, one way.
Symport
A type of active transport that moves two molecules at a time in the same direction, simultaneously
Antiport
A type of active transport where two molecules are moved at the same time, one goes in and one goes out. This is the export system for many antibiotics and toxic compounds.
ABC transporters
A type of active transport where one molecule is moved at a time with a special peripheral binding protein that cleaves ATP. In gram- found in periplasmic space; in gram+ found as tethered lipoproteins on the external phospholipid bilayer.
Coupled Symport and Antiport
The type of transport that proton and sodium pumps used.
Autotrophs
Use inorganic carbon.
Heterotrophs
Use organic carbon
Phototrophs
Capture energy from sunlight. Examples include cyanobacteria, purple & green sulfur bacteria.
Chemotrophs
Oxidize organic or inorganic molecules for energy. For example, an organic source would be glucose, while an inorganic source would be H2 (hydrogenomonas), H2S or FeS2 (thiobacillus), and NO2- (nitrobacter)
Organotrophs
Reduce organic molecules such as glucose for their electron/hydrogen source.
Lithotrophs
Reduce inorganic molecules such as H2S for their electron/hydrogen source.
Major elements
N,P,S,O. These are necessary for proteins, carbohydrates, nuclei acids, and lipids
Trace elements
Co, Mo, Mn, Zn, Cu. These are necessary for enzyme cofactors, vitamins,
Growth factors
Components that cannot be synthesized by an organism from the essential elements. Includes purines & pyrimidines, vitamins, and certain amino acids.
Complex media
A type of culture media that contains things like meat extracts, protein digests like peptone, yeast extract, The exact chemical formula that is needed is not known because you don't know what your bacteria needs. Examples include broth, nutrient agar, and blood agar.
Chemically defined
A type of culture media that contains pure chemicals like NaCl, glucose, MgSO4. It is buffered to maintain a neutral pH. This is used when it is known what the organism needs.
Selective media
A type of specialty culture media that allows the growth of a few kinds of organisms while inhibiting the growth of others. Example - Thayer-Martin agar.
Thayer-Martin agar
A type of selective specialty media that contains antibiotics that inhibit all but Neisseria sp.
Diplo
pairs of bacterial cells
Strepto
chains of bacterial cells
Staphylo
cluster of bacterial cells
Tetrads
"squares" of 4 bacterial cells
Sarcina
cubical packets of 8 bacterial cells
Differential media
a type of specialty media that does not inhibit any bacteria from growing. Different media is used to identify microorganisms by the appearance of their colonies. example: streptococcus pyogenes (the bacteria that causes strep throat) can be identified by blood agar because on this medium, S. pyogenes colonies are surrounded by a clear zone because they lyse (destroy by bursting) nearby red blood cells
MacConkey agar
contains crystal violet which inhibits the growth of Gram + bacteria and bile salt-tolerant; only bacteria that will grow are Gram - and bile salt-tolerant
Pure culture
A colony of bacteria arising from a single original parental cell
Streak plate
A loopful of bacteria is diluted over the surface of an agar plate. The loop if sterilized with ethanol and put through a flame to burn off the excess ethanol. This process is NOT quantitative
Spread plate
Bacteria are diluted in a known volume of diluent. A specific volume is placed on the surface of the agar and spread over it to evenly distribute cells. Cells grow up on the surface of agar. It IS quantitative.
Pour plate
sample is diluted, mixed with liquid agar, poured into sterile culture dishes. It is quantitative.