Chapter 4 Flashcards
What is the glycocalyx?
Surface coating formed from repeating polysaccharide units
What is the slime layer?
A loosely formed layer around the cell that prevents water and nutrient loss
What is sporulation?
Spore formation induced by environmental conditions
What is a bacterial species?
A collection of bacterial cells which share an overall pattern of similar traits
What are mycoplasmas?
Cells that display extreme variations in shape due to a lack of cell walls
What is negative chemotaxis?
Movement of a cell away from a repellant and/or harmful compound
What conditions can endospores resist?
Heating, drying, freezing, radiation, chemicals
What are the three main life activities that bacteria carry out?
Reproduction, metabolism, nutrient processing
What is the S layer?
A layer composed of thousands of copies of a single protein that forms when cells need protection from hostile environments
What is the composition of the cytoplasm?
Water, mixture of sugars, amino acids, and salts, cell parts such as the chromatin body, ribosomes, granules, and cytoskeleton
What is the average size of a bacterial cell?
1 micrometer
What prefix indicates that bacteria are in groups of four?
Tetrad
What is a monotrichous flagellar arrangement?
Single flagellum
What is the stimulus for endospore formation?
Depletion of nutrients
What are the characteristics of bacterial chromosomes?
Single circular strand of DNA, aggregated in the nucleoid, tightly coiled around basic protein molecules
What is peptidoglycan?
A unique macromolecule composed of glycan chains cross-linked with short peptide fragments
What conditions favor germination of an endospore?
Exposure to water and a germination agent
What is chemotaxis?
Movement in response to chemical signals
What are fimbriae?
Small bristle-like fibers composed of protein that stick to each other and to surfaces
What are the functions of teichoic and lipoteichoic acid in the gram-positive cell wall?
Cell wall maintenance, enlargement during cell division, acidic charge on cell surface
What prefix indicates that bacteria are in irregular clusters?
Staphylo
What are porin proteins?
Proteins found in gram-negative bacteria that span the outer membrane and allow for penetration by relatively small molecules
What is a peritrichous flagellar arrangement?
Flagella dispersed randomly over the cell surface
What are the characteristics of a gram-negative cell envelope?
Outer membrane, thin cell wall, inner cytoplasmic membrane
What is the cytoplasm?
Gelatinous solution contained by the cytoplasmic membrane
What is a lophotrichous flagellar arrangement?
Small bunches/tufts of flagella
What layers compose the cell envelope?
Cell wall, cytoplasmic membrane, and sometimes the outer membrane
What are sarcina formations?
Cubical packets of 8, 16, or more cocci cells
Why are endospores of medical significance?
They are resistant to ordinary cleaning methods and can frequently contaminate cultures, media, and other surfaces
What are the functions of the cytoplasmic membrane?
Energy reactions, nutrient processing, synthesis, regulate transport
What is subspecies/strain/type?
Bacteria of the same species that have differing characteristics
What is a polar flagellar arrangement?
Flagella at one or both ends of the cell
What function do capsules serve for pathogenic bacteria?
Protect pathogenic bacteria against phagocytic white blood cells
What are plasmids?
Nonessential pieces of DNA that confer protective traits
What is conjugation?
Partial transfer of DNA from one cell to another
What is positive chemotaxis?
Movement of a cell in the direction of a favorable stimulus
What is mycolic acid?
A long-chain fatty acid that contributes to the pathogenicity of Mycobacterium and makes them resistant to certain chemicals and dyes
What is secretion?
The discharge of metabolic products into the extracellular environment
What is an amphitrichous flagellar arrangement?
Flagella at both poles of the cell
What is lipopolysaccharide?
A polysaccharide found in gram-negative bacteria that functions as a cell marker and receptor; can act as an endotoxin to stimulate fever and shock
What are the three bacterial shapes?
Coccus, bacillus, and vibrio
What are the characteristics of the bacterial cytoskeleton?
Long polymers of proteins, arranged in helical ribbons, contribute to cell shape
How are bacteria and archaea different from eukaryotes?
Have nuclear material that is free in the cytoplasm and have no membrane-bound organelles
What are the characteristics of a gram-positive cell envelope?
Thick cell wall composed of peptidoglycan, inner cytoplasmic membrane
What formation do spirochetes typically form?
Individual cells
What are the characteristics of mycoplasma cell membranes?
Stabilized by sterols, resistant to lysis
What prefix indicates that bacteria are in pairs?
Diplo
What characteristics do gram-negative bacteria have due to their thin cell walls?
Greater flexibility, higher sensitivity to lysis
What is the role of pili and fimbriae?
To provide attachment
What is a serotype?
Representatives of a species that stimulate a distinct pattern of antibody responses
What is a sporangium?
A sporulating cell
What are pili?
Long, rigid, tubular structures formed from pilin protein, found only in gram-negative bacteria, used in conjugation
What are the two major groups of appendages?
- Flagella and axial filaments: motility
2. Fimbriae, pili, nanowires: attachment/channels
What formation do spirilla bacteria typically form?
Short chains
What is pleomorphism?
Variations in size and shape among cells of a single species
What is the capsule?
A more tightly bound, thicker, and denser protective layer than a slime layer
What are palisade formations?
Partially attached chains of bacilli cells that can create side-by-side rows
What is the defining characteristic of endospores?
Ability to withstand hostile conditions and facilitate survival
What is a run?
Counterclockwise movement of flagella that leads to a cell swimming in a smooth, linear direction
What is a tumble?
Flagellum reverses direction, causing cell to stop and change course
What are the two phases of bacterial lifestyle?
Vegetative cell and endospore
What are the functions of the cell wall?
Help determine bacterium shape, provide structural support to prevent cell from bursting or collapsing
What prefix indicates that bacteria are in chains?
Strepto
What are the two forms of bacterial groups?
Colonies and biofilms
How does the outer membrane impact gram-negative bacteria?
Makes them resistant to some antimicrobial chemicals; makes them harder to inhibit/kill than gram-positive bacteria
What are inclusion bodies?
Storage sites for nutrients during times of abundance
