Glossary of Microbiology: Chapter 3

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ABC Protein Secretion Pathway or Type I Secretion Pathway
Transport system that use ATP hydrolysis to drive translocation across the plasma membrane. They require an extracytoplasmic substrate-binding protein for proper function. Often called ATP-binding cassette transport
A cell with a a single flagellum at each end
Axial Filament
The organ of motility in spirochetes. It is made of axial fibrils or periplasmic flagella that extend from each end of the protoplasmic cylinder and overlap in the middle of the cell. The outer sheath lies outside the axial filament
A rod-shaped bacterium
Basal Body
The cylindrical structure at the base of procaryotic and eucaryotic flagella that attaches them to the cell
A layer of well-organized material, not easily washed off, lying outside the bacterial cell wall
Polyhedral inclusion bodies that contain the CO2 fixation enzyme ribulose 1,5-biphosphate carboxylase; found in cyanobacteria, nitrifying bacteria, and thiobacilli
Special protein receptors in the plasma membrane or periplasmic space that bind chemicals and trigger the appropriate chemotaxic response
The pattern of microbial behavior in which the microorganism moves toward chemical attractants and/or away from repellents
A roughly spherical bacterial cell
The core has the normal cell structures such as ribosomes and a nucleoid, but is metabolically inactive
Core Polysaccharide
It is joined to lipid A
The layer of bacterial endospore that is thought to be particualrly important in conferring hear resistance on the endospore
Cyanophycin Granules
One of two distinctive organic inclusion bodies of cyanobacteria. They are composed of large polypeptides containing approxiamately equal amounts of the amino acids arginine and aspartic acid.
Cytoplasmic Matrix
The protoplasm of a cell that lies within the plasma membrane and outside any other organelles. In bacteria it is the substance betweenteh cell membrande and the nucleoid.
Deoxyribosenucleic Acid (DNA)
The nucleic acid that constitutes teh genetic material of all cellular organisms. It is a polynucleotide composed of deoxyribosenucleotides connected by phosphodiester bonds
Dipicolinic Acid
A substance present at high concentrations in the bacterial endospore. It is thought to contribute to the endospore's heat resistance
A pair of cocci
An extremely heat- and chemical-resistant, dormant, thick-walled spore that develops within bacteria
1.All the structures outside the plasma membrane in bacterial cells. 2.In virology it is an outer membranous layer that surrounds the nucleocapsid in some viruses
Enzymes that are secreted by cells
A thin, delicate covering of the spore
One of three parts of a flagellum; the longest and most obvious portion, it extends from the cell surface to the tip
A fine, hairlike protein appendage on some gram-negative bacteria that helps attach them to surfaces
A thin, threadlike appendage on many procaryotic and eucaryotic cells that is responsible for their motility
The protein used to construct the filamnet of teh bacterial flagellum
Fluid Mosaic Model
The currently accepted model of cell membranes in which the membrane is a lipid bilayer with integral proteins buried in the lipid, and peripheral proteins more loosely attached to the membrane surface
Gas Vacuole
A gas-filled vacuole found in cyanobacteria and some other aquatic bacteria that provides flotation. It is composed of gas vesicles, which are made of protein
Gas Vesicles
Small, hollow, cylindrical structures taht make up gas vacuoles. They do not contain lipid and are composed entirely of a single small protein
General Secretion Pathway (GSP)
System that can transport proteins through the plasma membrane or insert tehm into the membrane. The bacterial translocon recognizes a signal peptide, and employs secYEG, SecA, and chaperones such as SecB
The stage following bacterial endospore activation in which the endospore breaks its dormant state. Germination is followed by outgrowth
Gliding Motility
A type of motility in which a microbial cell glides along when in contact with a solid surface
A network of polysaccharides extending from the surface of bacteria and other cells
A highly branched polysaccharide containing glucose, which is used to store carbon and energy
One of three parts of a flagellum; It is a short, curved segment that links the filamnet to its basal body and actws as a flexible coupling
A polar substance that has a strong affinity for water (or is readily soluble in water)
A nonpolar substance lacking affinity for water (or which is not readily soluble in water)
Inclusion Bodies
Granules of orgranic or inorganic material lying in the cytoplasmic matrix of bacteria
Integral Proteins
Make up about 70 to 80% of membrane proteins; They are not easily extracted from membranes and are insoluble in aqueous solutions when freed of lipids
Lipid A
One of the three parts that make up lipopolysaccharides (LPSs). This region contains tow glucosamine sugar derivatives, each with fatty acids and phosphates or pyrophosphate attached
A molecule containing both lipid and polysaccharide, which is important in the outer membrane of the gram-negative cells
A cell with a cluster of flagella at one or both ends
The rupture or physical disintegration of a cell
An enzyme that degrades peptidoglycan by hydrolyzing the B(1^4) bond that joins N-acetylmuramic acid and N-acetylglucosamine
Magnetite particles in magnetotactic bacteria that are tiny magnets and allow the bacteria to orient themselves in magnetic fields
Metachromatic Granules
Granules of polyphosphate in the cytoplasm of some bacteria that appear a different color when stained with a blue basic dye. They are storage reservoirs for phosphate. Sometimes called volutin granules.
Having a single flagellum
Murein or Peptidoglycan
A large polymer composed of long chains of alternating N-acetylglucosamine and N-acetylmuramic acid residues. The polysaccharide chains are linked to each other through connections between tetrapeptide chains attached to the N-am acids. It provides much of the strength and rigidity possessed by bacterial cell walls
An irregularly shaped region in the procaryotic cell that cotains its genetic material
O Antigen or O Side Chain
A polysaccharide antigen extending from the outer membrane of some gram-negative bacterial cell walls; it is part of the lipopolysaccharide
The movement of water across a selectively permeable membrane from a dilute sol'n (higher water conc) to a more concentrated sol'n
Outer Membrane
A special membrane located outside the peptidoglycan layer in the cell walls of gram-negative bacteria
A group of antibiotics containing a B-lactam ring, which are active against gram-positive bacteria
Peptide Interbridge
A short peptide chain that connects the tetrapeptide chains in some peptidoglycan
Peripheral Proteins
They are loosly connected the membrane and can easily be removed. They are soluble in aqueous sol'ns and make up 20 to 30% of membrane proteins.
The substance that fills the periplasmic space
Periplasmic Space
The space between the plasma membrane and the outer membrane in gram-negative bacteria, and between the plasma membrane and the cell wall in gram-positive bacteria
A cell with flagella evenly distributed over its surface
Plasma Membrane
The selectively permeable membrane surrounding the cell's cytoplasm, plasmalemma, or cytoplasmic membrane.
A double-stranded DNA molecule that can exist and replicate independently of the choromosome or may be integrated with it. It is stably inherited, but is not required for the host cell's growth and reproduction
The process in which water osmotically leaves a cell, which causes the cytoplasm to shrivel up and pull the plasma membrane away from the cell wall
Refers to bacteria that are variable in shape and lack a single, characteristic form
Polar Flagellum
A flagellum located at one end of an elongated cell
Poly-B-Hydroxybutyrate (PHB)
A linear polymer of B-hydroxybutyrate used as a reserve of carbon and energy by many bacteria
Polyphosphate or volutin granules
They function as storage reservoirs for phosphate
Porin Proteins
Proteins that form channels across the outer membrane of gram-negative bacterial cell walls. Small molecules are transported through these channels
A bacterial or fungal cell with its cell wall completely removed. It is spherical in shape and osmotically sensitive
The organelle where protein synthesis occurs; the message encoded in mRNA is translated here
Slime Layer
A layer of diffuse, unorganized, easily removed material lying outside the bacterial cell wall
The straight line movement of a bacterium
Sec-Depepndent Pathway
System that can transport proteins through the plasma membrane or insert them into the membrane. The bacterial translocon recognizes a signal peptide, and employs SecYEG, SecA, and chaperones such as SecB
The Spontaneous formation of a complex structure from its component molecules without the aid of special enzymes or factors
Sex Pilus
A thin protein appendage required for bacterial mating or conjugation. The cell with sex pili donates DNA to recipient cells
Signal Peptide
The special amino-terminal secquence on a peptide destined for transport that delays protein folding and is recognized in bacteria by the Sec-dependent pathway machinery
A regularly structured layer composed of protein or glycoprotein that lies on the surface of many bacteria. It may protect the bacterium and help give it shape and rigidity
A relatively spherical cell formed ny the weakening or partial removal of the rigid cell wall component (eg by penicillin treatment of gram-neg bacteria). They are usually osmotically sensitive
A rigid, spiral-shaped bacterium
A flexible, spiral-shaped bacterium with periplasmic flagella
A saclike structure or cell, the contents of which are converted into an indefinite number of spores. It is borne on a special hypha called a sporangiophore
Spore Cell Wall (or core wall)
Is inside the cortex and surrounds the protoplast or core
Spore Coat
Lies beneath the exosporium and is composed of several protein layers & may be fairly thick. It is impermeable to many toxic molecules & responsible for the spore's resistance to chemicals(also thought to contain enzymes for germination)
Sporogenesis or Sporulation
The process of spore formation
Svedberg Unit
The unit used in expressing the sedimentation coefficient; the greater a particle's Svedberg value, the faster is travels in a centrifuge
Teichoic Acid
Poymers of glycerol or ribitol joined by phosphates; they are found in the cell walls of gram-pos bacteria
The machinery that transports proteins across membranes. Usually refers to the Sec machinery
Tumble or Twiddle
Random turning or tumbling movements made by bacteria when they stop moving in a straight line
Type II Protein Secretion Pathway
A system that transports proteins from the periplasm to across the outer membrane of gram-neg bacteria
Type III Protein Secretion Pathway
A system in gram-neg bacteria that secretes virulence factors and injects them into host cells
A rod-shaped bacterial cell that is curved to form a comma or an incomplete spiral

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