lecture 2 Flashcards
capsule
a polysaccharide or protein outermost layer, usually rather slimy, present on some bacteria
pili
thin, filamentous structures that extend from the surface of a cell and, depending on type, facilitate cell attachment, genetic exchange or twitching motility
gas vesicles
gas-filled cytoplasmic structures bounded by a single layered protein membrane that confer buoyancy on cells
endospore
a highly heat-resistant, thick-walled, differentiated structure produced by certain gram-positive bacteria
dipicolinic acid
a substance unique to endospores which, when complexed with Ca2+, confers heat resistance on these structures
flagellum
a long, thin cellular appendage that rotates in bacteria or has a whiplike motion in eukarya and is responsible for swimming motility
archaellum
a long, thin cellular appendage present in some archaea that rotates an is responsible for swimming motility
polar flagellation
having flagella emanating from one or both poles of the cell
peritrichous flagellation
having flagella located in many places around the surface of the cell
basal body
the “motor” portion of the bacterial flagellum, embedded in the cytoplasmic membrane and cell wall
twitching motility
a form of surface motility caused by extension and retraction of type IV pili
gliding motility
a form of surface motility characterized by smooth continuous movement
chemotaxis
directed movement of an organism toward (positive chemotaxis) or away from (negative chemotaxis) a chemical gradient
phototaxis
movement of an organism toward light
