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